TWI489682B - Active material for lithium secondary battery, electrode for lithium secondary battery, lithium secondary battery and fabricating method thereof - Google Patents

Description

鋰二次電池用活性物質、鋰二次電池用電極、鋰二次電池及其製造方法 Active material for lithium secondary battery, electrode for lithium secondary battery, lithium secondary battery, and method of producing the same

本發明是有關於一種鋰二次電池用活性物質、使用該鋰二次電池用活性物質的鋰二次電池及其製造方法。 The present invention relates to an active material for a lithium secondary battery, a lithium secondary battery using the active material for a lithium secondary battery, and a method for producing the same.

先前，鋰二次電池中主要使用LiCoO₂作為正極活性物質。然而，放電電容為120mAh/g~130mAh/g左右。 Previously, LiCoO ₂ was mainly used as a positive electrode active material in a lithium secondary battery. However, the discharge capacity is about 120 mAh/g to 130 mAh/g.

已知有使LiCoO₂與其他化合物形成固溶體的材料。具有α-NaFeO₂型結晶構造，作為LiCoO₂、LiNiO₂及LiMnO₂三種成分之固溶體的Li[Co_1-2xNi_xMn_x]O₂(0<x≦1/2)已於2001年發表。將作為上述固溶體的一例的LiNi_1/2Mn_1/2O₂或LiCo_1/3Ni_1/3Mn_1/3O₂用作活性物質的鋰二次電池，其放電電容為150mAh/g~180mAh/g，優於LiCoO₂。 A material which forms a solid solution of LiCoO ₂ and other compounds is known. It has a crystal structure of α-NaFeO ₂ type, and Li[Co _1-2x Ni _x Mn _x ]O ₂ (0<x≦1/2) which is a solid solution of three components of LiCoO ₂ , LiNiO ₂ and LiMnO ₂ has been produced in 2001. Published in the year. A lithium secondary battery using LiNi _1/2 Mn _1/2 O ₂ or LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ as an example of the above solid solution as an active material has a discharge capacity of 150 mAh/ g~180mAh/g, better than LiCoO ₂ .

非專利文獻1~非專利文獻4中，提出有具有α-NaFeO₂型結晶構造的Li[Li_1/3Mn_2/3]O₂、LiNi_1/2Mn_1/2O₂及LiCoO₂三種成分的固溶體。該材料如可表現為Li[Li,Mn,Ni,Co]O₂般，於具有α-NaFeO₂型結晶構造的LiCoO₂中，於Co存在的位點(site)，除了過渡金屬以外存在Li。因此，可期待更高的放電電容，於非專利文獻1~非專利文獻4中，報告了180mAh/g~200mAh/g左右的放電電容。 Non-Patent Document 1 to Non-Patent Document 4 propose three kinds of Li[Li _1/3 Mn _2/3 ]O ₂ , LiNi _1/2 Mn _1/2 O ₂ and LiCoO ₂ having an α-NaFeO ₂ type crystal structure. A solid solution of the ingredients. This material can be expressed as Li[Li, Mn, Ni, Co]O ₂ , in LiCoO ₂ having an α-NaFeO ₂ type crystal structure, in the site where Co exists, Li exists in addition to the transition metal. . Therefore, a higher discharge capacity can be expected, and in Non-Patent Document 1 to Non-Patent Document 4, a discharge capacitance of about 180 mAh/g to 200 mAh/g is reported.

然而，謀求放電電容更大的鋰二次電池用活性物質。 However, an active material for a lithium secondary battery having a larger discharge capacity is sought.

關於以異種元素將鋰二次電池用正極活性物質所用的過渡金屬化合物的一部分過渡金屬位點(site)替換的嘗 試，正方晶尖晶石構造的LiMn₂O₄等其他活性物質的例子不勝枚舉，已進行了大量研究。然而，異種元素替換所帶來的效果是就各種活性物質而不同，該技術領域中，不言而喻，完全難以預測不同材料所表現出的效果是否在其他材料的情況下也同樣地表現出。 An attempt to replace a part of a transition metal site of a transition metal compound used for a positive electrode active material for a lithium secondary battery with a different element, and examples of other active materials such as LiMn ₂ O _{4 having a} tetragonal spinel structure are numerous. A lot of research has been done. However, the effect of replacement of different elements is different for various active substances, and it is self-evident in the technical field that it is completely difficult to predict whether the effects exhibited by different materials are similarly exhibited in the case of other materials. .

非專利文獻5中記載，以Mg來替換LiCoO₂的一部分Co，結果室溫下的電子傳導率提昇(參照圖2(Fig.2))，但放電電容由於Mg的添加而降低(參照Fig.6、Fig.8)。 Non-patent document 5 describes that a part of Co of LiCoO ₂ is replaced by Mg, and as a result, the electron conductivity at room temperature is increased (see Fig. 2 (Fig. 2)), but the discharge capacity is lowered by the addition of Mg (see Fig. 6, Fig. 8).

非專利文獻6中記載，以Mg來替換相當於LiCoO₂、LiNiO₂及LiMnO₂三種成分的固溶體的LiCo_1/3Ni_1/3Mn_1/3O₂的一部分過渡金屬位點，結果仍然是放電電容降低(參照Fig.8)。 Non-Patent Document 6 discloses that a part of transition metal sites of LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ corresponding to a solid solution of three components of LiCoO ₂ , LiNiO ₂ and LiMnO ₂ are replaced by Mg, and as a result, a transition metal site of LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ corresponding to a solid solution of LiCoO ₂ , LiNiO ₂ and LiMnO ₂ is replaced by Mg. Still the discharge capacitance is reduced (see Fig. 8).

非專利文獻7中記載，以Mg來替換相當於Li[Li_1/3Mn_2/3]O₂及LiNi_1/2Mn_1/2O₂兩種成分的固溶體的Li[Li_0.15Ni_0.275Mn_0.575]O₂的一部分過渡金屬位點，結果雖然伴隨著反覆充放電的電容維持率可見提高，但初期放電電容仍然降低(參照Fig.2)。另外，所報告的放電電容不超過200mAh/g(參照該圖)。 Non-Patent Document 7 discloses that Li[Li _0.15 Ni, which is a solid solution corresponding to two components of Li[Li _1/3 Mn _2/3 ]O ₂ and LiNi _1/2 Mn _1/2 O ₂ , is replaced by Mg. A part of the transition metal sites of _0.275 Mn _0.575 ]O ₂ results in an increase in the capacitance retention rate accompanying the charge and discharge, but the initial discharge capacity is still lowered (see Fig. 2). In addition, the reported discharge capacitance does not exceed 200 mAh/g (refer to the figure).

另外，專利文獻1中記載有「一種正極活性物質，其將Li[Mn_cNi_dCo_eLi_aM”_b]O₂(M”為選自由B、Mg、Al、Ti、V、Cr、Fe、Cu及Zn所組成的組群中的至少一種元素，d≦c+e+a+b、c+d+e+a+b=1、0≦a≦0.05、0≦b≦0.05、0.2≦c≦0.5、0.02≦e≦0.4)所表示的複合氧化物作為主成分，該正極活性物質的特徵在於：由布厄特 (Brunauer-Emmett-Teller，BET)法所得的比表面積為0.3m²/g以上、1.5m²/g以下，具有可歸屬於空間群R3/m的X射線繞射圖案，2θ=44.1±1°時的繞射波峰相對於2θ=18.6±1°時的繞射波峰的相對強度比為0.6以上、1.1以下，並且2θ=18.6±1°時的繞射波峰的半高寬(half width)為0.13°以上、0.20°以下，且2θ=44.1±1°時的繞射波峰的半高寬為0.10°以上、0.17°以下，粒徑為3μm以上、20μm以下」(申請專利範圍第6項)的發明；亦揭示，藉由使用將上述相對強度比設定為0.6以上、1.1以下的正極活性物質，可提供兼具良好的高率放電性能與良好的充放電循環性能的非水電解質二次電池(段落[0031]~段落[0032])；但並未揭示，於採用Mg作為M”的特定組成的活性物質的上述相對強度比在特定範圍內時，放電電容顯著提高，另外於採用Mg作為M”的特定組成的活性物質的活性物質的半高寬在特定範圍內時，高率放電特性顯著提高。 Further, Patent Document 1 describes "a positive electrode active material in which Li[Mn _c Ni _d Co _e Li _a M" _b ]O ₂ (M" is selected from the group consisting of B, Mg, Al, Ti, V, Cr, At least one element selected from the group consisting of Fe, Cu, and Zn, d≦c+e+a+b, c+d+e+a+b=1, 0≦a≦0.05, 0≦b≦0.05, The composite oxide represented by 0.2≦c≦0.5, 0.02≦e≦0.4) is used as a main component, and the positive electrode active material is characterized in that the specific surface area obtained by the Brunauer-Emmett-Teller (BET) method is 0.3 m. ² / g or more and 1.5 m ² /g or less, having an X-ray diffraction pattern attributable to the space group R3 / m, and a diffraction peak at 2θ = 44.1 ± 1° with respect to 2θ = 18.6 ± 1° The relative intensity ratio of the radiation peak is 0.6 or more and 1.1 or less, and the half width of the diffraction peak at 2θ=18.6±1° is 0.13° or more and 0.20° or less, and 2θ=44.1±1°. The invention has the invention that the half-height width of the diffraction peak is 0.10° or more and 0.17° or less, and the particle diameter is 3 μm or more and 20 μm or less (see Patent Application No. 6). It is also disclosed that the relative intensity ratio is set to be Positive electrode activity of 0.6 or more and 1.1 or less Quality, can provide a non-aqueous electrolyte secondary battery with good high rate discharge performance and good charge and discharge cycle performance (paragraph [0031] ~ paragraph [0032]); but does not disclose, using Mg as M" When the above-mentioned relative intensity ratio of the active material of a specific composition is within a specific range, the discharge capacity is remarkably improved, and when the full width at half maximum of the active material of the active material using Mg as the specific composition of M" is within a specific range, high rate discharge Significantly improved characteristics.

專利文獻2中記載有「一種正極活性物質，其含有組成式Li_aMn_0.5-xNi_0.5-yM_x+yO₂(其中0<a<1.3、-0.1≦x-y≦0.1，M為Li、Mn、Ni以外的元素)所表示的複合氧化物」(申請專利範圍第1項)；另外記載有「申請專利範圍第2項的正極活性物質的特徵在於：含有上述M為選自Al、Mg及Co所組成的組群中的至少一種元素且上述組成式中的係數滿足下述關係式的複合氧化物(0.05≦x<0.3、0.05≦y<0.3、-0.1≦x-y≦0.02、0<a<1.3、x+y<0.5)。根據此種構成，特別可形成能製造高率 放電性能及充放電循環性能優異、高能量密度的非水電解質二次電池的正極活性物質」(第6頁自下往上第7行~第7頁第4行)、「申請專利範圍第5項的正極活性物質的特徵在於：上述複合氧化物的總孔隙體積為...以下，且使用CuKα射線的粉末X射線繞射圖的2θ=44.1±1°時的繞射波峰相對於2θ=18.6±1°時的繞射波峰的相對強度比為0.65以上、1.05以下。根據此種構成，特別可形成能製造高率放電性能及充放電循環性能優異、高能量密度(高放電電容)的非水電解質二次電池的正極活性物質」(第8頁自下往上第4行~第9頁第3行)、「申請專利範圍第6項的正極活性物質的特徵在於：上述複合氧化物的比表面積為...以下，且使用CuKα射線的粉末X射線繞射圖的2θ=44.1±1°時的繞射波峰相對於2θ=18.6±1°時的繞射波峰的相對強度比為0.65以上、1.05以下。根據此種構成，特別可形成能製造高率放電性能及充放電循環性能優異、高能量密度(高放電電容)的非水電解質二次電池的正極活性物質」(第9頁第4行~第10行)，但並未揭示，於採用Mg作為M的特定組成的活性物質的上述相對強度比在特定範圍內時，放電電容顯著提高。 Patent Document 2 describes "a positive electrode active material containing a composition formula of Li _a Mn _0.5-x Ni _0.5-y M _x+y O ₂ (where 0 < a < 1.3, -0.1 ≦ xy ≦ 0.1, M is Li a composite oxide represented by an element other than Mn or Ni. (Application No. 1 of the patent application), and a positive electrode active material according to the second aspect of the invention is characterized in that the M is selected from the group consisting of Al, At least one element of the group consisting of Mg and Co and the coefficient in the above composition formula satisfies the composite oxide of the following relationship (0.05≦x<0.3, 0.05≦y<0.3, -0.1≦xy≦0.02,0) <a < 1.3, x + y < 0.5). According to such a configuration, a positive electrode active material capable of producing a nonaqueous electrolyte secondary battery having high rate discharge performance and high charge and discharge cycle performance and high energy density can be formed. 6th page from the bottom to the seventh row - page 7 and 4th row), "The positive electrode active material of the fifth application patent is characterized in that the total pore volume of the above composite oxide is ... or less, and CuKα is used. The relative intensity ratio of the diffraction peak at 2θ=44.1±1° of the powder X-ray diffraction pattern relative to the diffraction peak at 2θ=18.6±1° In particular, it is possible to form a positive electrode active material capable of producing a nonaqueous electrolyte secondary battery having high rate discharge performance and charge/discharge cycle performance and high energy density (high discharge capacity). The fourth embodiment of the present invention is characterized in that: the positive electrode active material of the sixth aspect of the invention is characterized in that the specific surface area of the composite oxide is ... or less, and CuKα ray is used. The relative intensity ratio of the diffraction peak at 2θ=44.1±1° of the powder X-ray diffraction pattern to the diffraction peak at 2θ=18.6±1° is 0.65 or more and 1.05 or less. A positive electrode active material capable of producing a nonaqueous electrolyte secondary battery having high rate discharge performance and excellent charge/discharge cycle performance and high energy density (high discharge capacity) (page 9, line 4 to line 10), but not It is revealed that the discharge capacity is remarkably improved when the above relative intensity ratio of the active material using Mg as a specific composition of M is within a specific range.

另外記載有「申請專利範圍第7項的正極活性物質的特徵在於：上述2θ：18.6±1°時的繞射波峰的半高寬為0.05°以上、0.20°以下，且上述2θ：44.1±1°時的繞射波峰的半高寬為0.10°以上、0.20°以下。根據此種構成，特別可形成能製造具有高能量密度(高放電電容)、充放電循環性能 優異的非水電解質二次電池的正極活性物質」(第9頁第11行~第16行)，但並未揭示，於採用Mg作為M的特定組成的活性物質的上述繞射波峰的半高寬在特定範圍內時，高率放電特性顯著提高。 Further, the positive electrode active material of the seventh aspect of the invention is characterized in that the full width at half maximum of the diffraction peak at the above 2θ: 18.6±1° is 0.05° or more and 0.20° or less, and the above 2θ: 44.1±1 The half-height width of the diffraction peak at °° is 0.10° or more and 0.20° or less. According to this configuration, it is possible to form a high energy density (high discharge capacity) and charge and discharge cycle performance. An excellent positive electrode active material for a nonaqueous electrolyte secondary battery (page 9, line 11 to line 16), but does not disclose a half height of the above-mentioned diffraction peak of an active material using Mg as a specific composition of M When the width is within a specific range, the high rate discharge characteristics are remarkably improved.

專利文獻3中揭示有「一種鋰二次電池用活性物質，其含有具有α-NaFeO₂型結晶構造的鋰過渡金屬複合氧化物的固溶體，且該鋰二次電池用活性物質的特徵在於：上述固溶體所含有的Li、Co、Ni及Mn的組成比滿足Li_1+1/3xCo_1-x-yNi_y/2Mn_2x/3+y/2(x+y≦1、0≦y、1-x-y=z)，於Li[Li_1/3Mn_2/3]O₂(x)-LiNi_1/2Mn_1/2O₂(y)-LiCoO₂(z)系三角相圖中，(x,y,z)是以存在於以點A(0.45,0.55,0)、點B(0.63,0.37,0)、點C(0.7,0.25,0.05)、點D(0.67,0.18,0.15)、點E(0.75,0,0.25)、點F(0.55,0,0.45)及點G(0.45,0.2,0.35)作為頂點的七角形ABCDEFG的線上或內部的範圍的值來表示，並且，由X射線繞射測定所得的(003)面與(104)面的繞射波峰的強度比於充放電前為I(003)/I(104)≧1.56、於放電末為I(003)/I(104)>1」(申請專利範圍第1項)的發明、「一種鋰二次電池的製造方法，其是採用充電時的正極的最大到達電位為4.3V(vs.Li/Li+)以下的充電方法的用以製造如申請專利範圍第9項所述之鋰二次電池的製造方法，其特徵在於包括以下步驟：進行在超過4.3V(vs.Li/Li+)、且為4.8V以下(vs.Li/Li+)的正極電位範圍中出現的電位變化至少達到相對較平坦區域的充電」(申請專利範圍第10項)的發明，另外 記載有「於先前的活性物質中，由於生成此種無序(disorder)相，故不發生來自Li層的順暢的Li離子的移動，一般認為亦影響可逆電容。相對於此，本發明的活性物質中，由於I(003)/I(104)≧1.56，故disorder相的生成極少，一般認為可獲得優異的放電電容」(段落[0068])；作為實例，亦揭示了由X射線繞射測定所得的(003)面與(104)面的繞射波峰的強度比於充放電前為I(003)/I(104)=1.77、於放電末為I(003)/I(104)=1.67，且放電電容達到225mAh/g的鋰二次電池用活性物質，但該活性物質不含有Mg，並未揭示於含有Mg的特定組成的活性物質的上述相對強度比在特定範圍內時，放電電容顯著提高。 Patent Document 3 discloses an active material for a lithium secondary battery containing a solid solution of a lithium transition metal composite oxide having an α-NaFeO ₂ type crystal structure, and the active material for a lithium secondary battery is characterized in that The composition ratio of Li, Co, Ni, and Mn contained in the above solid solution satisfies Li _1+1/3x Co _1-xy Ni _y/2 Mn _2x/3+y/2 (x+y≦1, 0≦) y, 1-xy=z), in the triangular phase diagram of Li[Li _1/3 Mn _2/3 ]O ₂ (x)-LiNi _1/2 Mn _1/2 O ₂ (y)-LiCoO ₂ (z) system Where (x, y, z) is present at point A (0.45, 0.55, 0), point B (0.63, 0.37, 0), point C (0.7, 0.25, 0.05), point D (0.67, 0.18) , 0.15), point E (0.75, 0, 0.25), point F (0.55, 0, 0.45), and point G (0.45, 0.2, 0.35) are represented as the values of the on-line or inner range of the octagonal ABCDEFG. Further, the intensity ratio of the diffraction peaks of the (003) plane and the (104) plane obtained by the X-ray diffraction measurement is I(003)/I(104)≧1.56 before charge and discharge, and I(003) at the end of discharge. In the invention of the first aspect of the invention, "a method for producing a lithium secondary battery, wherein the maximum reaching potential of the positive electrode during charging is 4.3 V (vs. Li/Li+) The following charging method A method for producing a lithium secondary battery according to claim 9, which comprises the steps of: performing over 4.3 V (vs. Li/Li+) and being 4.8 V or less (vs. Li) The invention in which the potential change occurring in the positive electrode potential range of /Li+) reaches at least the charging of the relatively flat region (Patent No. 10) is additionally described as "in the prior active matter, due to the generation of such disorder ( Since the phase of the disorder does not cause the smooth movement of Li ions from the Li layer, it is considered that the reversible capacitance is also affected. In contrast, in the active material of the present invention, since I(003)/I(104)≧1.56, The generation of the disorder phase is extremely small, and it is generally considered that an excellent discharge capacity can be obtained" (paragraph [0068]); as an example, the diffraction peaks of the (003) plane and the (104) plane obtained by X-ray diffraction measurement are also disclosed. The active material for lithium secondary batteries having an intensity ratio of I(003)/I(104)=1.77 before charge and discharge, I(003)/I(104)=1.67 at the end of discharge, and a discharge capacitance of 225 mAh/g However, the active material does not contain Mg and is not disclosed in the above relative activity of the active substance containing a specific composition of Mg. When the intensity ratio is within a specific range, the discharge capacitance is remarkably improved.

而且，將專利文獻3所記載的固溶體作為活性物質的鋰二次電池如後述的比較例般，有無法獲得高率放電時的電容的問題。 In addition, the lithium secondary battery using the solid solution described in Patent Document 3 as an active material has a problem that a capacitor at a high rate of discharge cannot be obtained as in the comparative example described later.

專利文獻4中記載有「一種具有Li_aNi_xMn_yCo_zO_2+b(x+y+z=1、1.00<a<1.3、0≦b<0.3)的化學組成的層狀構造的鋰‧鎳‧錳‧鈷複合氧化物，該複合氧化物的使用CuKα射線的粉末X射線繞射的米勒指數(Miller index)hkl的(003)面及(104)面的繞射波峰角2θ分別為18.65°以上及44.50°以上，且該些各面的繞射波峰半高寬均為0.18°以下，進而(108)面及(110)面的繞射波峰角2θ分別為64.40°及65.15°以上，且該些各面的繞射波峰半高寬均為0.18°以下」(申請專利範圍第1項)的發明；另外 記載有「若使用CuKα射線的粉末X射線繞射的米勒指數hkl的(003)面及(104)面的繞射波峰角2θ分別小於18.65°、44.50°，則相間隔減少，鋰離子的擴散受到抑制，充‧放電特性劣化。另外，若該些面的繞射波峰半高寬分別大於0.18°，則可能結晶的成長不充分而組成的偏差大，故充‧放電特性劣化」(段落[0017])，但未揭示(003)面及(104)面的繞射波峰半高寬(半高寬)與高率放電特性的關係。 Patent Document 4 describes "a layered structure having a chemical composition of Li _a Ni _x Mn _y Co _z O _2+b (x+y+z=1, 1.00<a<1.3, 0≦b<0.3). Lithium ‧ nickel ‧ manganese ‧ cobalt composite oxide, the diffraction peak angle 2θ of the (003) plane and the (104) plane of the Miller index hkl using the powder X-ray diffraction of the CuKα ray The diffraction peaks have a half-height width of 0.18° or less, and the diffraction peak angles 2θ of the (108) plane and the (110) plane are 64.40° and 65.15, respectively. And above, and the half-height widths of the diffraction peaks of the respective surfaces are all 0.18° or less (the first paragraph of the patent application); and the Miller index of the powder X-ray diffraction using the CuKα ray is also described. The diffraction peak angle 2θ of the (003) plane and the (104) plane of hkl is less than 18.65° and 44.50°, respectively, and the phase interval is reduced, the diffusion of lithium ions is suppressed, and the charge and discharge characteristics are deteriorated. When the half-height width of the diffraction peak is greater than 0.18°, the crystal growth may be insufficient and the composition variation may be large, so that the charge and discharge characteristics are deteriorated (paragraph [0017]), but not Relational characteristics shown in (003) plane diffraction peak and the (104) plane half width (FWHM) and the high-rate discharge.

專利文獻5中記載有「一種正極活性物質，其特徵在於：含有可歸屬於空間群R-3m、相當於(104)面的X射線繞射波峰的半高寬在0.06°~0.15°的範圍內、且由下述(1)式所算出的形狀係數SF1的平均值在大於1且為3.3以下的範圍內的含鋰金屬複合氧化物粒子。...」(申請專利範圍第1項)的發明；另外揭示：於含鋰金屬複合氧化物粒子的結晶構造歸屬於空間群R-3m、且相當於(104)面的X射線繞射波峰的半高寬在0.06°~0.15°的範圍內時，可獲得較高的放電負荷特性(高率放電特性)；以及若半高寬超過0.15°，則含鋰金屬複合氧化物的結晶性下降而難以獲得高的高率放電特性(段落[0025])；但關於使含鋰金屬複合氧化物含有Mg則完全無記載，且並未啟示，藉由將含有Mg的含鋰金屬複合氧化物的繞射波峰的半高寬設定為特定範圍而高率放電特性顯著提高。 Patent Document 5 describes "a positive electrode active material characterized by containing a half-height width of an X-ray diffraction peak which is attributable to a space group R-3m and corresponding to a (104) plane in a range of 0.06 to 0.15. Lithium-containing metal composite oxide particles having an average value of the shape factor SF1 calculated by the following formula (1) in a range of more than 1 and 3.3 or less. (" Patent Application No. 1) Further, it is disclosed that the crystal structure of the lithium-containing metal composite oxide particles belongs to the space group R-3m, and the full width at half maximum of the X-ray diffraction peak corresponding to the (104) plane is in the range of 0.06° to 0.15°. In the case of internal, a high discharge load characteristic (high rate discharge characteristic) can be obtained; and if the full width at half maximum exceeds 0.15°, the crystallinity of the lithium-containing metal composite oxide is lowered and it is difficult to obtain high high rate discharge characteristics (paragraph [ 0025]); however, there is no description about the inclusion of Mg in the lithium-containing metal composite oxide, and it is not suggested that the half-height width of the diffraction peak of the lithium-containing metal composite oxide containing Mg is set to a specific range. High rate discharge characteristics are significantly improved.

專利文獻6中記載有「可藉由在本發明的LiNi_1/3Mn_1/3Co_1/3O₂中摻雜異種元素而表現出附加功能，可 藉由添加鎂而使電子傳導性飛躍性地提昇」(段落[0077])；另外亦揭示，可使用使鋰原子比增加的Li[Li_x(Ni_1/3Mn_1/3Co_1/3]_1-x]O₂(式中，0≦x≦0.3)所表示的氧化物，以乾式方式將共沈澱所得的複合氧化物與氫氧化鋰混合並於1000℃下煅燒而成的鎳錳鈷複合氧化物是屬於層構造R3m的六方晶系(段落[0028]~[0030])；但並未啟示，於鎳錳鈷複合氧化物中含有鎂作為固溶體成分時，放電電容顯著提高，高率放電特性顯著提高。 Patent Document 6 describes that "addition of a dissimilar element to LiNi _1/3 Mn _1/3 Co _1/3 O ₂ of the present invention exhibits an additional function, and electron transfer can be made by the addition of magnesium. Sexually improved" (paragraph [0077]); it is also disclosed that Li[Li _x (Ni _1/3 Mn _1/3 Co _1/3 ] _1-x ]O ₂ can be used to increase the lithium atomic ratio (wherein , the oxide represented by 0≦x≦0.3), the nickel manganese cobalt composite oxide obtained by mixing the composite oxide obtained by coprecipitation with lithium hydroxide in a dry manner and calcining at 1000 ° C belongs to a layer structure R3m Hexagonal system (paragraphs [0028] to [0030]); however, it has not been suggested that when magnesium is contained as a solid solution component in the nickel manganese cobalt composite oxide, the discharge capacity is remarkably improved, and the high rate discharge characteristics are remarkably improved.

專利文獻7中記載有「一種鋰二次電池正極材料用鋰鎳錳鈷系複合氧化物粉體，其是含有歸屬於層狀構造的結晶構造而構成，且其組成是以下述(I)式所表示，Li[Li_z/(2+z){(Li_xNi_(1-3x)/2Mn_(1+x)/2)_(1-y)Co_y}_2/(2+z)]O₂...(I) Patent Document 7 discloses a lithium nickel manganese-cobalt composite oxide powder for a lithium secondary battery positive electrode material, which is composed of a crystal structure belonging to a layered structure, and has a composition of the following formula (I). It is expressed that Li[Li _z/(2+z) {(Li _x Ni _(1-3x)/2 Mn _(1+x)/2 ) _(1-y) Co _y } _2/(2+z) ] O ₂ ...(I)

(其中，0.01≦x≦0.15、0≦y≦0.35、0.02(1-y)(1-3x)≦z≦0.15(1-y)(1-3x))」(申請專利範圍第6項)的發明；且揭示，重要的是Li量在較化學計量組成稍許富餘(rich)的範圍內，藉此電池性能(特別是速率特性或輸出特性)提高(段落[0014]及段落[0015])，但並未啟示，於鋰鎳錳鈷系複合氧化物為含有鎂的特定組成時，放電電容顯著提昇，高率放電特性顯著提昇。 (Where, 0.01≦x≦0.15, 0≦y≦0.35, 0.02(1-y)(1-3x)≦z≦0.15(1-y)(1-3x))” (Scope 6 of the patent application) Invention; and reveals that it is important that the amount of Li is within a slightly richer range of stoichiometric composition, whereby battery performance (especially rate characteristics or output characteristics) is improved (paragraphs [0014] and [0015]) However, it has not been suggested that when the lithium nickel manganese cobalt composite oxide is a specific composition containing magnesium, the discharge capacity is remarkably improved, and the high rate discharge characteristics are remarkably improved.

另外，專利文獻1~專利文獻7中記載的鋰二次電池用正極活性物質並非設想為Li[Li_1/3Mn_2/3]O₂、LiNi_1/2Mn_1/2O₂、LiCoO₂及LiMg_1/2Mn_1/2O₂四種成分的固溶 體，因此即便如上所述的正極活性物質假使含有Mg、且滿足相對強度比的條件，自非專利文獻5~非專利文獻7的記載來看亦無法期待放電電容提高。 In addition, the positive electrode active material for a lithium secondary battery described in Patent Document 1 to Patent Document 7 is not assumed to be Li[Li _1/3 Mn _2/3 ]O ₂ , LiNi _1/2 Mn _1/2 O ₂ , or LiCoO _{2 .} And a solid solution of the four components of the LiMg _1/2 Mn _1/2 O ₂ , the non-patent document 5 to the non-patent document 7 are not included in the case where the positive electrode active material as described above contains Mg and satisfies the relative strength ratio. According to the records, it is impossible to expect an increase in discharge capacitance.

[先前技術文獻] [Previous Technical Literature]

[非專利文獻] [Non-patent literature]

[非專利文獻1]Electrochim.Acta, vol.51, page 5581-5586, 2006. [Non-Patent Document 1] Electrochim. Acta, vol. 51, page 5581-5586, 2006.

[非專利文獻2]J.Power Sources, vol.146, page 598-601, 2005. [Non-Patent Document 2] J. Power Sources, vol. 146, page 598-601, 2005.

[非專利文獻3]J.Electrochem.Soc., vol.152, no.1, page A171-A178, 2005. [Non-Patent Document 3] J. Electrochem. Soc., vol. 152, no. 1, page A171-A178, 2005.

[非專利文獻4]Mater.Lett., vol.58, page 3197-3200, 2004. [Non-Patent Document 4] Mater. Lett., vol. 58, page 3197-3200, 2004.

[非專利文獻5]J.Electrochem.Soc., vol.144, page 3164-3168, 1997. [Non-Patent Document 5] J. Electrochem. Soc., vol. 144, page 3164-3168, 1997.

[非專利文獻6]Solid State Ionics, vol.178, page 849-857, 2007. [Non-Patent Document 6] Solid State Ionics, vol. 178, page 849-857, 2007.

[非專利文獻7]J.Mater.Chem., vol 13, page 319-322, 2003. [Non-Patent Document 7] J. Mater. Chem., vol 13, page 319-322, 2003.

[專利文獻] [Patent Literature]

[專利文獻1]日本專利第4320548號公報 [Patent Document 1] Japanese Patent No. 4320548

[專利文獻2]WO 2002/086993 A1 [Patent Document 2] WO 2002/086993 A1

[專利文獻3]WO 2009/063838 A1 [Patent Document 3] WO 2009/063838 A1

[專利文獻4]日本專利第4216669號公報 [Patent Document 4] Japanese Patent No. 4216669

[專利文獻5]日本專利2003-178756號公報 [Patent Document 5] Japanese Patent No. 2003-178756

[專利文獻6]日本專利2003-17052號公報 [Patent Document 6] Japanese Patent No. 2003-17052

[專利文獻7]日本專利2006-253119號公報 [Patent Document 7] Japanese Patent No. 2006-253119

本發明是鑒於上述問題而成，其課題在於提供一種放電電容大、高率放電特性優異的鋰二次電池用活性物質及使用該鋰二次電池用活性物質的鋰二次電池。 The present invention has been made in view of the above problems, and an object of the invention is to provide an active material for a lithium secondary battery having a large discharge capacity and high rate discharge characteristics, and a lithium secondary battery using the active material for a lithium secondary battery.

對本發明的構成及作用效果夾雜技術思想來進行說明。其中，作用機制包括推定，其正確與否並不限制本發明。再者，本發明可於不偏離其精神或主要特徵的情況下以其他多種形態來實施。因此，後述實施形態或實驗例於所有方面僅不過為例示，而非限定性地解釋。進而，屬於申請專利範圍的均等範圍的變形或變更全部在本發明的範圍內。 The technical concept of the configuration and effects of the present invention will be described. Among them, the mechanism of action includes presumption, and its correctness does not limit the present invention. Further, the present invention can be embodied in other various forms without departing from the spirit or essential characteristics thereof. Therefore, the embodiments or experimental examples described below are merely illustrative and not restrictive in all respects. Further, variations or modifications of the equivalent scope of the claims are all within the scope of the invention.

具有α-NaFeO₂型結晶構造、可表現為Li[Li,Mn,Ni,Co]O₂的材料需留意存在於過渡金屬位點的各金屬元素的價數。即，於合成可表現為Li[Li,Mn,Ni,Co]O₂的材料時，並非任意設定作為原料所含的金屬元素的Li、Co、Ni及Mn的組成比率，而是在存在於過渡金屬位點時的各金屬元素的價數成為Li¹⁺、Mn⁴⁺、Ni²⁺、Co³⁺的條件下設定各金屬元素的比率，並且於使用如此般合成的材料的X射線繞射圖中繞射波峰的半高寬在特定範圍內的物質作為鋰二次電池用活性物質時，可表現出高的放電電容。 A material having an α-NaFeO ₂ type crystal structure and exhibiting Li[Li, Mn, Ni, Co]O ₂ should pay attention to the valence of each metal element present at the transition metal site. In other words, when a material which can be expressed as Li[Li, Mn, Ni, Co]O ₂ is synthesized, the composition ratio of Li, Co, Ni, and Mn which are metal elements contained in the raw material is not arbitrarily set, but is present in The ratio of each metal element is set under the condition that the valence of each metal element at the transition metal site becomes Li ¹⁺ , Mn ⁴⁺ , Ni ²⁺ , Co ³⁺ , and the X-ray is used in the material thus synthesized. When a substance having a half-height width of a diffraction peak in a specific range is used as an active material for a lithium secondary battery, a high discharge capacity can be exhibited.

各金屬元素的價數成為Li¹⁺、Mn⁴⁺、Ni²⁺、Co³⁺的條 件可藉由設想Li[Li_1/3Mn_2/3]O₂、LiNi_1/2Mn_1/2O₂及LiCoO₂三種成分的固溶體而提供。即，藉由設想xLi[Li_1/3Mn_2/3]O₂-yLiNi_1/2Mn_1/2O₂-(1-x-y)LiCoO₂(其中，x>0、y>0、x+y<1)，並任意選擇x及y，理論上可使α-NaFeO₂型結晶構造的存在於過渡金屬位點的各金屬元素的價數為Li¹⁺、Mn⁴⁺、Ni²⁺、Co³⁺。 The condition that the valence of each metal element becomes Li ¹⁺ , Mn ⁴⁺ , Ni ²⁺ , and Co ³⁺ can be assumed by considering Li[Li _1/3 Mn _2/3 ]O ₂ , LiNi _1/2 Mn _1/2 A solid solution of three components of O ₂ and LiCoO ₂ is provided. That is, by considering xLi[Li _1/3 Mn _2/3 ]O ₂ -yLiNi _1/2 Mn _1/2 O ₂ -(1-xy)LiCoO ₂ (where x>0, y>0, x+ y<1), and arbitrarily select x and y, theoretically, the valence of each metal element present in the transition metal site of the α-NaFeO ₂ type crystal structure is Li ¹⁺ , Mn ⁴⁺ , Ni ²⁺ , Co ³⁺ .

本發明的鋰二次電池用活性物質的特徵在於含有Mg，但此時亦需留意存在於過渡金屬位點的金屬元素的價數。即，藉由在存在於過渡金屬位點時的各金屬元素的價數成為Li¹⁺、Co³⁺、Ni²⁺、Mn⁴⁺、Mg²⁺的條件下設定各金屬元素的比率，本發明的效果顯著表現出。 The active material for a lithium secondary battery of the present invention is characterized by containing Mg, but at this time, it is also necessary to pay attention to the valence of the metal element present at the transition metal site. That is, the ratio of each metal element is set under the condition that the valence of each metal element present at the transition metal site becomes Li ¹⁺ , Co ³⁺ , Ni ²⁺ , Mn ⁴⁺ , and Mg ²⁺ . The effects of the invention are remarkably exhibited.

此處，於保持成為Li¹⁺、Mn⁴⁺、Ni²⁺、Co³⁺、Mg²⁺的條件下設定Mg比率時，可採用若干種想法。第一想法是根據藉由Mg²⁺ _1/2Mn⁴⁺ _1/2來替換構成所設想的LiNi_1/2Mn_1/2O₂的Ni²⁺ _1/2Mn⁴⁺ _1/2部分的思想而設定Mg比率的方法，本案說明書中作為實例2-1~實例2-6而加以具體詳述。第二想法是根據藉由[Mg_1/2Mn_1/2]³⁺來替換構成所設想的Li[Li_1/3Mn_2/3]O₂的[Li_1/3Mn_2/3]³⁺部分的思想而設定Mg比率的方法，本案說明書中作為實例2-7~實例2-10而加以具體詳述。第三想法是想到根據藉由[Mg_1/2Mn_1/2]³⁺來替換Co³⁺的思想而設定Mg比率的方法。另外想到將這些思想中的2個或3個重複應用的方法。 Here, when setting the Mg ratio under the conditions of maintaining Li ¹⁺ , Mn ⁴⁺ , Ni ²⁺ , Co ³⁺ , and Mg ²⁺ , several ideas can be employed. The first idea is to replace the Ni ²⁺ _1/2 Mn ⁴⁺ _1/2 moiety constituting the envisioned LiNi _1/2 Mn _1/2 O ₂ by Mg ²⁺ _1/2 Mn ⁴⁺ _1/2 The method of setting the Mg ratio by thinking is described in detail in the present specification as Example 2-1 to Example 2-6. The second idea is to replace [Li _1/3 Mn _2/3 ] ³ constituting the envisioned Li[Li _1/3 Mn _2/3 ]O ₂ by [Mg _1/2 Mn _1/2 ] ^{3+ +} partial thinking method set Mg ratio, and to be specific details as an example of the specification of examples 2-7 to 2-10. The third idea is to think of a method of setting the Mg ratio based on the idea of replacing Co ³⁺ by [Mg _1/2 Mn _1/2 ] ³⁺ . Also think of a method of repeatedly applying 2 or 3 of these ideas.

於採用上述任意想法時可知，各金屬元素的價數成為Li¹⁺、Mn⁴⁺、Ni²⁺、Co³⁺、Mg²⁺的條件可藉由設想 Li[Li_1/3Mn_2/3]O₂、LiNi_1/2Mn_1/2O₂、LiCoO₂及LiMg_1/2Mn_1/2O₂四種成分的固溶體而提供。即，藉由設想固溶體xLi[Li_1/3Mn_2/3]O₂-yLiNi_1/2Mn_1/2O₂-zLiMg_1/2Mn_1/2O₂-(1-x-y-z)LiCoO₂(x>0、y>0、z>0、x+y+z<1)並任意選擇x、y及z，理論上可使存在於α-NaFeO₂型結晶構造的過渡金屬位點的各金屬元素的價數為Li¹⁺、Co³⁺、Ni²⁺、Mn⁴⁺、Mg²⁺。 When using any of the above ideas, it can be understood that the condition that the valence of each metal element becomes Li ¹⁺ , Mn ⁴⁺ , Ni ²⁺ , Co ³⁺ , Mg ²⁺ can be assumed by considering Li [Li _1/3 Mn _2/3 A solid solution of four components of O ₂ , LiNi _1/2 Mn _1/2 O ₂ , LiCoO ₂ and LiMg _1/2 Mn _1/2 O ₂ is provided. That is, by envisioning a solid solution xLi[Li _1/3 Mn _2/3 ]O ₂ -yLiNi _1/2 Mn _1/2 O ₂ -zLiMg _1/2 Mn _1/2 O ₂ -(1-xyz)LiCoO ₂ (x>0, y>0, z>0, x+y+z<1) and arbitrarily select x, y and z, which can theoretically exist in the transition metal sites of the α-NaFeO ₂ type crystal structure The valence of each metal element is Li ¹⁺ , Co ³⁺ , Ni ²⁺ , Mn ⁴⁺ , and Mg ²⁺ .

若將上述式xLi[Li_1/3Mn_2/3]O₂-yLiNi_1/2Mn_1/2O₂-zLiMg_1/2Mn_1/2O₂-(1-x-y-z)LiCoO₂加以變形，則可一意地獲得式Li_1+(x/3)Co_1-x-y-zNi_y/2Mg_z/2Mn_{(2x/3)+(y/2)+(z/2)}O₂。此處，本發明是一種鋰二次電池用活性物質，其含有具有α-NaFeO₂型結晶構造的鋰過渡金屬複合氧化物的固溶體，且該鋰二次電池用活性物質的特徵在於：上述固溶體所含有的金屬元素的組成比率滿足Li_1+(x/3)Co_1-x-y-zNi_y/2Mg_z/2Mn_{(2x/3)+(y/2)+(z/2)}(x>0、y>0、z>0、x+y+z<1)，具有可歸屬於空間群P3₁12的X射線繞射圖案，且具有超過200mAh/g的放電電容。 If the above formula xLi[Li _1/3 Mn _2/3 ]O ₂ -yLiNi _1/2 Mn _1/2 O ₂ -zLiMg _1/2 Mn _1/2 O ₂ -(1-xyz)LiCoO _{2 is} deformed, Then, Li _1+(x/3) Co _1-xyz Ni _y/2 Mg _z/2 Mn _{(2x/3)+(y/2)+(z/2)} O ₂ can be obtained by the intention. Here, the present invention is an active material for a lithium secondary battery comprising a solid solution of a lithium transition metal composite oxide having an α-NaFeO ₂ type crystal structure, and the active material for a lithium secondary battery is characterized by: The composition ratio of the metal element contained in the above solid solution satisfies Li _1+(x/3) Co _1-xyz Ni _y/2 Mg _z/2 Mn _{(2x/3)+(y/2)+(z/2 ) (x> 0, y>} 0, z> 0, x + y + z <1), having an X-ray diffraction pattern attributable to the space group P3 ₁ 12, and has more than 200mAh / g discharge capacity.

如後述的比較例所示，即便是滿足上述金屬元素的組成比率、且具有可歸屬於空間群P3₁12的X射線繞射圖案的活性物質，有時放電電容亦為200mAh/g以下，而本發明是於上述活性物質中，限定於由後述充放電循環試驗所得的放電電容超過200mAh/g的活性物質。 As shown in the comparative example described later, even if the active material satisfies the composition ratio of the metal element and has an X-ray diffraction pattern that can be attributed to the space group P3 ₁ 12, the discharge capacity may be 200 mAh/g or less. In the present invention, the active material is limited to an active material having a discharge capacity of more than 200 mAh/g obtained by a charge and discharge cycle test described later.

為了使上述活性物質具有超過200mAh/g的放電電 容，煅燒溫度的影響大，藉由將滿足上述金屬元素的組成比率的鋰過渡金屬複合氧化物的固溶體於超過900℃的溫度、例如920℃以上的溫度下煅燒，可獲得具有超過200mAh/g的放電電容的活性物質。若煅燒溫度超過1000℃，則有時無法獲得具有可歸屬於空間群P3₁12的X射線繞射圖案的活性物質，故較佳為1000℃以下。 In order to make the above-mentioned active material have a discharge capacity of more than 200 mAh/g, the influence of the calcination temperature is large, and the solid solution of the lithium transition metal composite oxide satisfying the composition ratio of the above metal elements is at a temperature exceeding 900 ° C, for example, 920. Calcination at a temperature above °C can obtain an active material having a discharge capacity of more than 200 mAh/g. When the calcination temperature exceeds 1000 ° C, an active material having an X-ray diffraction pattern attributable to the space group P3 ₁ 12 may not be obtained, and therefore it is preferably 1000 ° C or lower.

本發明首次發現，於將上述含有Mg的鋰過渡金屬複合氧化物的固溶體製成具有超過200mAh/g的大的放電電容的活性物質時，高率放電特性亦顯著提高。 In the present invention, it has been found for the first time that when the solid solution of the above-mentioned Mg-containing lithium transition metal composite oxide is made into an active material having a large discharge capacity of more than 200 mAh/g, the high rate discharge characteristics are remarkably improved.

滿足上述金屬元素的組成比率、且具有可歸屬於空間群P3₁12的X射線繞射圖案的活性物質就特性的觀點來看，例如於由X射線繞射測定所得的(003)面與(114)面的繞射波峰的強度比為I₍₀₀₃₎/I₍₁₁₄₎≧1.15時，及/或(003)面的繞射波峰的半高寬為0.15°以下、且(114)面的繞射波峰的半高寬為0.25°以下時，具有超過200mAh/g的放電電容。 From the viewpoint of satisfying the composition ratio of the above-described metal element and having an X-ray diffraction pattern attributed to the space group P3 ₁ 12, for example, the (003) plane obtained by X-ray diffraction measurement 114) When the intensity ratio of the diffraction peak of the surface is I ₍₀₀₃₎ / I ₍₁₁₄₎ ≧ 1.15, and/or the half-height of the diffraction peak of the (003) plane is 0.15° or less, and (114) plane When the half-height of the diffraction peak is 0.25 or less, the discharge capacitance exceeds 200 mAh/g.

通常，若經由煅燒步驟來合成具有α-NaFeO₂型結晶構造的鋰過渡金屬複合氧化物，並對實際獲得的化合物進行化學分析而求出元素組成比，則事實上可知，與根據原料的添加組成比而計算的組成相比有稍許(5%左右)變動。不言而喻，本發明可於不偏離其技術思想或主要特徵的情況下實施，不應解釋為藉由合成而獲得的物質僅由於組成不與上述組成式嚴格一致而不屬於本發明之範圍。特別是關於Li量，已知於煅燒步驟中容易揮發。另外，氧原子的 係數亦可根據合成條件等而變動，並非嚴格限定於2的情況，不應解釋為由於氧缺損而不屬於本發明的範圍。再者，本發明中，規定金屬元素組成比的上述式中不規定氧的係數。 In general, when a lithium transition metal composite oxide having an α-NaFeO ₂ type crystal structure is synthesized by a calcination step, and an elemental composition ratio is obtained by chemically analyzing the actually obtained compound, it is actually known that There is a slight (about 5%) change in the composition calculated from the composition ratio. It is to be understood that the present invention may be carried out without departing from the technical spirit or main characteristics thereof, and should not be construed as a substance obtained by synthesis, which is not in the scope of the present invention only because the composition is not strictly consistent with the above composition formula. . In particular, regarding the amount of Li, it is known that it is easily volatilized in the calcination step. Further, the coefficient of the oxygen atom may vary depending on the synthesis conditions and the like, and is not strictly limited to 2, and should not be construed as being in the range of the present invention due to oxygen deficiency. Further, in the present invention, the coefficient of oxygen is not defined in the above formula in which the metal element composition ratio is specified.

另外，本發明的活性物質亦可含有Li、Co、Ni、Mn、Mg、O以外的元素，於含有Li、Co、Ni、Mn、Mg、O以外的元素時，本發明的活性物質亦要求構成上述固溶體的元素中，Li、Co、Ni、Mn及Mg的價數分別滿足Li¹⁺、Co³⁺、Ni²⁺、Mn⁴⁺、Mg²⁺的價數條件。再者，伴隨著電池的充放電而活性物質中的Li量變化，並且過渡金屬的價數亦變化，但即便是自充放電深度不明的電池所採取的活性物質，亦可藉由感應耦合電漿(Inductively Coupled Plasma，ICP)發光分光分析、X射線繞射測定、氧量分析等的組合而得知合成了該活性物質時的包含Li的金屬元素比率，因此，可判定該活性物質是否屬於本發明的技術範圍。 Further, the active material of the present invention may contain an element other than Li, Co, Ni, Mn, Mg, or O. When an element other than Li, Co, Ni, Mn, Mg, or O is contained, the active material of the present invention is also required. Among the elements constituting the above solid solution, the valences of Li, Co, Ni, Mn, and Mg satisfy the valence conditions of Li ¹⁺ , Co ³⁺ , Ni ²⁺ , Mn ⁴⁺ , and Mg ²⁺ , respectively. Furthermore, the amount of Li in the active material changes with the charge and discharge of the battery, and the valence of the transition metal also changes, but the active material taken by the battery whose self-charge and discharge depth is unknown may be inductively coupled. In the case of an inductively-coupled plasma (ICP) luminescence spectrometry, an X-ray diffraction measurement, an oxygen amount analysis, or the like, the ratio of the metal element containing Li when the active material is synthesized is known, and therefore, it can be determined whether the active material belongs to The technical scope of the present invention.

此處，將LiCoO₂粉末、LiNi_1/2Mn_1/2O₂粉末、Li[Li_1/3Mn_2/3]O₂粉末等簡單地製成混合物的粉體不可當作本發明的「固溶體」。該些材料的單品由於進行X射線繞射測定時所觀察到的各晶格常數所對應的波峰位置各不相同，故若對該些簡單的混合物進行X射線繞射測定，則可獲得各單品所對應的繞射圖案。 Here, a powder in which a mixture of LiCoO ₂ powder, LiNi _1/2 Mn _1/2 O ₂ powder, Li [Li _1/3 Mn _2/3 ]O ₂ powder, or the like is simply prepared cannot be regarded as "the present invention". Solid solution". Since the peak positions corresponding to the respective lattice constants observed in the X-ray diffraction measurement of the individual materials of the materials are different, if the simple mixture is subjected to X-ray diffraction measurement, each of the obtained products can be obtained. The diffraction pattern corresponding to the single product.

此處，藉由選擇1/3<x<2/3的範圍的值作為x，於將所合成的材料用作鋰二次電池用活性物質時可表現出相對 較高的放電電容，故較佳。x或y的值可考慮欲採用該鋰二次電池用活性物質的電池需求何種電池特性而適當選擇。z的值與Mg量相關，但如後述實例所示，即便Mg量為極少量，與不含Mg的情形相比亦顯著發揮提高放電電容的效果。反之，Mg由於即便進行充放電亦不發生價數變化，故過剩含有無益，較佳為不過分地大量含有。使z的值進行各種變化時的本發明的效果的表現方式是根據x或y的值而不同，故只要根據電池設計來決定採用的x、y的值，然後相對於該x、y的值根據上述技術思想使z的值變化，採用適當的z的值即可。為了使放電電容提高，較佳為0<y<2/3、0<z<0.3。 Here, by selecting a value of a range of 1/3<x<2/3 as x, the synthesized material can exhibit relative relative use as an active material for a lithium secondary battery. Higher discharge capacitance is preferred. The value of x or y can be appropriately selected in consideration of which battery characteristics are desired in the battery for which the active material for a lithium secondary battery is to be used. The value of z is related to the amount of Mg. However, as shown in the later example, even if the amount of Mg is extremely small, the effect of increasing the discharge capacity is remarkably exhibited as compared with the case where Mg is not contained. On the other hand, since Mg does not change the valence even if it is charged and discharged, the excess is not useful, and it is preferably not excessively contained. The expression of the effect of the present invention when the value of z is variously changed is different depending on the value of x or y. Therefore, the value of x and y to be used is determined according to the design of the battery, and then the value of x and y is then determined. According to the above technical idea, the value of z is changed, and an appropriate value of z can be used. In order to increase the discharge capacity, it is preferably 0 < y < 2 / 3 and 0 < z < 0.3.

如上所述，藉由「一種鋰二次電池用活性物質，其含有具有α-NaFeO₂型結晶構造的鋰過渡金屬複合氧化物的固溶體，且上述固溶體所含有的金屬元素的組成比率滿足Li_1+(x/3)Co_1-x-y-zNi_y/2Mg_z/2Mn_{(2x/3)+(y/2)+(z/2)}(x>0、y>0、z>0、x+y+z<1)」，可表現出高的放電電容；而於本發明中，為了使放電電容及高率放電特性顯著提高，而使上述鋰過渡金屬複合氧化物的固溶體具有可歸屬於空間群P3₁12的X射線繞射圖案，使由X射線繞射測定所得的(003)面與(114)面的繞射波峰的強度比為I(003)/I(114)≧1.15，及/或使(003)面的繞射波峰的半高寬為0.15°以下、且使(114)面的繞射波峰的半高寬為0.25°以下。 As described above, the active material for a lithium secondary battery contains a solid solution of a lithium transition metal composite oxide having an α-NaFeO ₂ type crystal structure, and the composition of the metal element contained in the solid solution The ratio satisfies Li _1+(x/3) Co _1-xyz Ni _y/2 Mg _z/2 Mn _{(2x/3)+(y/2)+(z/2)} (x>0, y>0, z >0, x+y+z<1)", which can exhibit high discharge capacitance; in the present invention, in order to significantly improve discharge capacitance and high rate discharge characteristics, the lithium transition metal composite oxide is solidified. The solution has an X-ray diffraction pattern attributable to the space group P3 ₁ 12 such that the intensity ratio of the diffraction peaks of the (003) plane and the (114) plane obtained by the X-ray diffraction measurement is I (003) / I (114) ≧ 1.15, and/or the half-height width of the diffraction peak of the (003) plane is 0.15° or less, and the full width at half maximum of the diffraction peak of the (114) plane is 0.25° or less.

再者，本發明的上述固溶體的X射線繞射圖可歸屬於 空間群P3₁12，但亦並非不可能歸屬於空間群R3-m。此時，歸屬於空間群P3₁12時的上述(114)面的繞射波峰於歸屬於空間群R3-m時必須另稱為「(104)面的繞射波峰」。此處，關於空間群的表述，「R3-m」原本應於「3」上標記短橫線(bar)「-」來表述，但本說明書中為方便起見而表述為「R3-m」。 Furthermore, the X-ray diffraction pattern of the above solid solution of the present invention can be attributed to the space group P3 ₁ 12, but it is not impossible to belong to the space group R3-m. At this time, the diffraction peak of the (114) plane attributed to the space group P3 ₁ 12 must be referred to as "the diffraction peak of the (104) plane" when it belongs to the space group R3-m. Here, regarding the expression of the space group, "R3-m" should originally be marked with a short bar (-) on "3", but this description is expressed as "R3-m" for convenience. .

使用本發明的鋰二次電池用活性物質，於使用時，即便採用充電時的正極的最大到達電位為4.3V(vs.Li/Li⁺)以下的充電方法，為了製造可取出充分的放電電容的鋰二次電池，重要的亦是如下述，於該鋰二次電池的製造步驟中設置考慮到本發明的鋰二次電池用活性物質的特徵性的行為的充電步驟。即，與專利文獻3中記載的鋰二次電池用活性物質相同，關於本發明的含有Mg的鋰二次電池用活性物質，亦是若將其用於正極並持續進行恆定電流充電，則如後述實例所示，於正極電位4.3V~4.8V的範圍中於相對較長期間內觀察到電位變化相對較平坦的區域。 When the active material for a lithium secondary battery of the present invention is used, a charging method in which the maximum reaching potential of the positive electrode during charging is 4.3 V (vs. Li/Li ⁺ ) or less is used, and a sufficient discharge capacitor can be taken out for production. In the lithium secondary battery, it is important to provide a charging step in which the characteristic behavior of the active material for a lithium secondary battery of the present invention is taken into consideration in the production step of the lithium secondary battery. In the same manner as the active material for a lithium secondary battery described in Patent Document 3, the active material for a lithium secondary battery containing Mg of the present invention is also used for a positive electrode and continuously charged at a constant current. As will be described later, in the range of the positive electrode potential of 4.3 V to 4.8 V, a region where the potential change was relatively flat was observed for a relatively long period of time.

此處，本發明是一種鋰二次電池的製造方法，其是採用充電時的正極的最大到達電位為4.3V(vs.Li/Li⁺)以下的充電方法的用以製造上述鋰二次電池的製造方法，其特徵在於包括以下步驟：進行超過4.3V(vs.Li/Li⁺)、且為4.8V以下(vs.Li/Li⁺)的正極電位範圍內出現的電位變化至少達到相對較平坦的區域的充電。 Here, the present invention is a method for producing a lithium secondary battery, which is a method for charging the lithium secondary battery using a charging method in which the maximum reaching potential of the positive electrode during charging is 4.3 V (vs. Li/Li ⁺ ) or less. The manufacturing method is characterized by comprising the steps of: performing a potential change occurring in a positive electrode potential range exceeding 4.3 V (vs. Li/Li ⁺ ) and being 4.8 V or less (vs. Li/Li ⁺ ) to at least relatively relatively Charging of flat areas.

此處，電池完成前的初期充放電步驟的充電必須進行到至少達到上述電位平坦區域為止。該電位平坦區域相對 較長地(例如100mAh/g以上)持續，故較好的是以儘可能經由該過程的方式持續充電。另外，於由於電位上升等而觀察到該電位平坦區域的終點時，亦可據此而設定為充電終止條件，亦可根據採用恆定電流恆定電壓充電而電流值衰減至設定值為止，而設定為充電終止條件。 Here, the charging of the initial charge and discharge step before the completion of the battery must be performed until at least the potential flat region is reached. The potential flat area is relative Longer (e.g., above 100 mAh/g) continues, so it is preferred to continue charging as much as possible through the process. In addition, when the end point of the potential flat region is observed due to an increase in potential or the like, the charge termination condition may be set accordingly, and the current value may be attenuated to a set value by constant current constant voltage charging, and may be set to Charge termination condition.

根據本發明，可提供一種放電電容大、且高率放電特性優異的鋰二次電池用活性物質。 According to the present invention, it is possible to provide an active material for a lithium secondary battery having a large discharge capacity and excellent high-rate discharge characteristics.

為讓本發明之上述和其他目的、特徵和優點能更明顯易懂，下文特舉較佳實施例，並配合所附圖式，作詳細說明如下。 The above and other objects, features and advantages of the present invention will become more <RTIgt;

對製造本發明的鋰二次電池用活性物質的方法加以說明。 A method of producing the active material for a lithium secondary battery of the present invention will be described.

本發明的鋰二次電池用活性物質基本上可藉由以下方式而獲得：對於構成活性物質的金屬元素(Li、Mn、Co、Ni、Mg)，如目標活性物質(氧化物)的組成般調整所含有的原料，並對其進行煅燒。其中，關於Li原料的量，預計煅燒中Li原料的一部分消失，故過剩添加1%~5%左右。 The active material for a lithium secondary battery of the present invention can be obtained basically by the following means: for a metal element (Li, Mn, Co, Ni, Mg) constituting the active material, such as a composition of a target active material (oxide) The raw materials contained are adjusted and calcined. Among them, regarding the amount of the Li raw material, it is expected that a part of the Li raw material in the calcination disappears, so an excess of about 1% to 5% is added.

製作目標組成的氧化物時，已知有：將Li、Co、Ni、Mn、Mg各自的鹽混合‧煅燒的所謂「固相法」；或預先製作於一粒子中存在Co、Ni、Mn、Mg的共沈澱前驅物，於其中將Li鹽混合‧煅燒的「共沈澱法」。利用「固相法」的合成過程中，特別是Mn相對於Co、Ni而難以均勻地固 溶，故難以獲得各元素於一粒子中均勻分布的試樣。迄今為止，於文獻等中已大量進行了欲藉由固相法於Ni或Co的一部分中固溶Mn的嘗試(LiNi_1-xMn_xO₂等)，但選擇「共沈澱法」更容易以原子水準獲得均勻相。因此，於後述實例中採用「共沈澱法」。再者，此種前驅物的較佳製作方法例如參考專利文獻2的記載。 When an oxide of a target composition is produced, a so-called "solid phase method" in which a salt of each of Li, Co, Ni, Mn, and Mg is mixed and calcined is known, or Co, Ni, and Mn are prepared in advance in one particle. A coprecipitated precursor of Mg in which a Li salt is mixed and a "coprecipitation method" of calcination is carried out. In the synthesis process by the "solid phase method", in particular, it is difficult to uniformly dissolve Mn with respect to Co and Ni, and it is difficult to obtain a sample in which each element is uniformly distributed in one particle. At present, attempts have been made to solid-dissolve Mn in a part of Ni or Co by a solid phase method (LiNi _1-x Mn _x O _{2 ,} etc.) in the literature, etc., but it is easier to select the "coprecipitation method". A homogeneous phase is obtained at atomic level. Therefore, the "coprecipitation method" is employed in the examples described later. Further, a preferred method for producing such a precursor is described, for example, in Patent Document 2.

於製作共沈澱前驅物時，使欲獲得共沈澱前驅物的溶液中為惰性環境極為重要。其原因在於，Co、Ni、Mn、Mg中Mn容易被氧化，不易製作Co、Ni、Mn、Mg以2價的狀態均勻分布的共沈澱氫氧化物，因此Co、Ni、Mn、Mg的原子水準的均勻混合容易變得不充分。特別是於本發明的組成範圍中，由於Mn比率高於Co、Ni比率，故使溶液中為惰性環境更為重要。後述實例中，於水溶液中將惰性氣體鼓泡(bubbling)而去除溶存氧，進而同時滴加還原劑。 In making a coprecipitated precursor, it is extremely important to make the solution in which the coprecipitate precursor is to be obtained an inert environment. The reason is that Mn is easily oxidized in Co, Ni, Mn, and Mg, and it is difficult to produce a coprecipitated hydroxide in which Co, Ni, Mn, and Mg are uniformly distributed in a divalent state, and thus atoms of Co, Ni, Mn, and Mg are formed. The uniform mixing of the levels tends to be insufficient. Particularly in the composition range of the present invention, since the Mn ratio is higher than the Co and Ni ratios, it is more important to make the solution inert. In the latter example, the inert gas is bubbling in an aqueous solution to remove dissolved oxygen, and the reducing agent is simultaneously added dropwise.

供於上述煅燒的前驅物的調整方法並無限定。可將Li化合物、Mn化合物、Ni化合物、Co化合物及Mg化合物單獨混合，亦可於溶液中使含有過渡金屬元素的氫氧化物共沈澱，並將其與Li化合物混合。為了製作均勻的複合氧化物，較佳為將Mn、Ni、Co及Mg的共沈澱化合物與Li化合物混合並進行煅燒的方法。 The method of adjusting the precursor for the above calcination is not limited. The Li compound, the Mn compound, the Ni compound, the Co compound, and the Mg compound may be separately mixed, or a hydroxide containing a transition metal element may be coprecipitated in a solution and mixed with the Li compound. In order to produce a uniform composite oxide, a method of mixing and calcining a coprecipitated compound of Mn, Ni, Co, and Mg with a Li compound is preferred.

關於上述共沈澱氫氧化物前驅物的製作，較佳為將Mn、Ni、Co及Mg均勻混合而成的化合物。其中，前驅物不限定於氫氧化物，除此以外，只要為碳酸鹽、檸檬酸 鹽等元素以原子水準均勻存在的難溶性鹽，則可與氫氧化物同樣地使用。另外，亦可藉由使用利用錯合劑的晶析反應等，而製作體積密度更大的前驅物。此時，由於可藉由與Li源混合‧煅燒而獲得更高密度且比表面積小的活性物質，故可使單位電極面積的能量密度提高。 The preparation of the coprecipitated hydroxide precursor is preferably a compound obtained by uniformly mixing Mn, Ni, Co, and Mg. Wherein, the precursor is not limited to hydroxide, and besides, as long as it is carbonate or citric acid A poorly soluble salt in which an element such as a salt is uniformly present at an atomic level can be used in the same manner as the hydroxide. Further, a precursor having a larger bulk density can also be produced by using a crystallization reaction or the like using a coupling agent. At this time, since the active material having a higher density and a smaller specific surface area can be obtained by mixing with the Li source and calcining, the energy density per unit electrode area can be improved.

關於上述共沈澱氫氧化物前驅物的原料，Mn化合物可列舉氧化錳、碳酸錳、硫酸錳、硝酸錳、乙酸錳等作為一例，Ni化合物可列舉氫氧化鎳、碳酸鎳、硫酸鎳、硝酸鎳、乙酸鎳等作為一例，Co化合物可列舉硫酸鈷、硝酸鈷、乙酸鈷等作為一例，Mg化合物可列舉硫酸鎂、硝酸鎂、乙酸鎂等作為一例。 Examples of the raw material of the coprecipitated hydroxide precursor include manganese oxide, manganese carbonate, manganese sulfate, manganese nitrate, manganese acetate, and the like. Examples of the Ni compound include nickel hydroxide, nickel carbonate, nickel sulfate, and nickel nitrate. Examples of the Co compound include cobalt sulfate, cobalt nitrate, cobalt acetate, and the like. Examples of the Mg compound include magnesium sulfate, magnesium nitrate, and magnesium acetate.

關於用於製作上述共沈澱氫氧化物前驅物的原料，只要可與鹼性水溶液形成沈澱反應，則任意形態均可使用，較佳為使用溶解度高的金屬鹽。 The raw material for producing the above-mentioned coprecipitated hydroxide precursor may be used in any form as long as it can form a precipitation reaction with an aqueous alkaline solution, and it is preferred to use a metal salt having a high solubility.

本發明的鋰二次電池用活性物質可藉由將上述共沈澱氫氧化物前驅物與Li化合物混合後進行熱處理而合適地製作。可藉由使用氫氧化鋰、碳酸鋰、硝酸鋰、乙酸鋰等作為Li化合物而合適地製造。 The active material for a lithium secondary battery of the present invention can be suitably produced by mixing the above-mentioned coprecipitated hydroxide precursor with a Li compound and then heat-treating it. It can be suitably produced by using lithium hydroxide, lithium carbonate, lithium nitrate, lithium acetate or the like as a Li compound.

於獲得放電電容顯著提高的活性物質時，煅燒溫度的選擇極為重要。 The choice of calcination temperature is extremely important in obtaining an active material with a significantly increased discharge capacitance.

如後述實例般，藉由將煅燒溫度設定為920℃~1000℃，「固溶體所含有的金屬元素的組成比率滿足Li_1+(x/3)Co_1-x-y-zNi_y/2Mg_z/2Mn_{(2x/3)+(y/2)+(z/2)}(x>0、y>0、z>0、x+y+z<1)的」鋰過渡金屬複合氧化物的固溶體具 有可歸屬於空間群P3₁12的X射線繞射圖案，且由X射線繞射測定所得的(003)面與(114)面的繞射波峰的強度比為I₍₀₀₃₎/I₍₁₁₄₎≧1.15，放電電容顯著提高。 As set forth below, by setting the calcination temperature to 920 ° C to 1000 ° C, "the composition ratio of the metal element contained in the solid solution satisfies Li _1+(x/3) Co _1-xyz Ni _{y / 2} Mg _{z / 2} Mn _{(2x/3)+(y/2)+(z/2)} (x>0, y>0, z>0, x+y+z<1) solidification of lithium transition metal composite oxide The solution has an X-ray diffraction pattern attributable to the space group P3 ₁ 12, and the intensity ratio of the diffraction peaks of the (003) plane and the (114) plane obtained by X-ray diffraction measurement is I ₍₀₀₃₎ /I ₍₁₁₄₎ ≧ 1.15, the discharge capacitance is significantly improved.

若煅燒溫度過高，則所得的活性物質伴隨著氧釋放反應而崩解，除了主相的六方晶以外單斜晶的Li[Li_1/3Mn_2/3]O₂型所規定的相不成為固溶相，而有分相而觀察到的傾向，此種材料由於活性物質的可逆電容大幅度地減少，故欠佳。此種材料於X射線繞射圖上35°附近及45°附近觀察到雜質波峰。因此，煅燒溫度重要的是設定為小於活性物質的氧釋放反應造成影響的溫度。活性物質的氧釋放溫度於本發明的組成範圍內大致為1000℃以上，但視活性物質的組成不同，氧釋放溫度有稍許偏差，故較佳為預先確認活性物質的氧釋放溫度。特別是由於確認到試樣所含的Co量越多則前驅物的氧釋放溫度越往低溫側移，故必須注意。關於確認活性物質的氧釋放溫度的方法，為了模擬煅燒反應過程，亦可將共沈澱前驅物與LiOH‧H₂O的混合物供於熱重量分析(DTA-TG測定)，但該方法可能測定機器的試樣室所用的鉑由於揮發的Li成分而受到腐蝕，損傷機器，故較好的是將預先採用500℃左右的煅燒溫度進行了某種程度的結晶化的組成物供於熱重量分析。 When the calcination temperature is too high, the obtained active material disintegrates with the oxygen release reaction, and the phase specified by the monoclinic Li[Li _1/3 Mn _2/3 ]O ₂ type other than the hexagonal crystal of the main phase is not There is a tendency to form a solid solution phase and it is observed by phase separation. Such a material is less preferable because the reversible capacitance of the active material is greatly reduced. This material observed impurity peaks around 35° and around 45° on the X-ray diffraction pattern. Therefore, it is important that the calcination temperature is set to a temperature lower than the influence of the oxygen release reaction of the active material. The oxygen release temperature of the active material is substantially 1000 ° C or more in the composition range of the present invention. However, depending on the composition of the active material, the oxygen release temperature is slightly different. Therefore, it is preferred to confirm the oxygen release temperature of the active material in advance. In particular, since it is confirmed that the amount of Co contained in the sample increases, the oxygen release temperature of the precursor shifts to the low temperature side, so care must be taken. Regarding the method of confirming the oxygen release temperature of the active material, in order to simulate the calcination reaction process, a mixture of the coprecipitated precursor and LiOH‧H ₂ O may be supplied to the thermogravimetric analysis (DTA-TG measurement), but the method may determine the machine. The platinum used in the sample chamber is corroded by the volatilized Li component and damages the machine. Therefore, it is preferred that the composition which has been crystallized to some extent by a calcination temperature of about 500 ° C in advance is subjected to thermogravimetric analysis.

另一方面，若煅燒溫度過低，則結晶化未充分進行，如後述比較例般，由X射線繞射測定所得的(003)面與(114)面的繞射波峰的強度比為I₍₀₀₃₎/I₍₁₁₄₎<1.15，放 電電容降低，故欠佳。本發明中，煅燒溫度必須設定為至少900℃以上。充分進行結晶化對於減輕晶界的阻抗、促進順暢的鋰離子輸送而言較為重要。結晶化程度的辨別方法可列舉使用掃描式電子顯微鏡的視覺觀察。對本發明的正極活性物質進行掃描式電子顯微鏡觀察時，若試樣合成溫度為800℃以下，則試樣是由奈米級的一次粒子形成，但藉由進一步提高試樣合成溫度而結晶化至次微米程度為止，而獲得伴有電極特性提昇的大的一次粒子。 On the other hand, when the calcination temperature is too low, the crystallization does not sufficiently proceed, and the intensity ratio of the diffraction peaks of the (003) plane and the (114) plane obtained by the X-ray diffraction measurement is I ₍ as in the comparative example described later). ₀₀₃₎ /I ₍₁₁₄₎ <1.15, the discharge capacitance is reduced, so it is not good. In the present invention, the calcination temperature must be set to at least 900 °C or higher. Sufficient crystallization is important to reduce the impedance of the grain boundaries and promote smooth lithium ion transport. The method of discriminating the degree of crystallization can be exemplified by visual observation using a scanning electron microscope. When the positive electrode active material of the present invention is observed by a scanning electron microscope, when the sample synthesis temperature is 800 ° C or lower, the sample is formed of primary particles of a nanometer order, but is further crystallized by further increasing the temperature of the sample synthesis. At a micron level, large primary particles accompanied by an increase in electrode characteristics are obtained.

另一方面，表示結晶化程度的另一標準有上文所述的X射線繞射波峰的半高寬。本發明中，為了提高不僅放電電容而且高率放電特性，較佳為於歸屬於空間群P3₁12的X射線繞射圖中使(003)面的繞射波峰的半高寬為0.15°以下，且使(114)面的繞射波峰的半高寬為0.25°以下。(003)面的繞射波峰的半高寬更佳為0.14°~0.15°，(114)面的繞射波峰的半高寬更佳為0.23°~0.25°。 On the other hand, another standard indicating the degree of crystallization is the full width at half maximum of the X-ray diffraction peaks described above. In the present invention, in order to improve not only the discharge capacitance but also the high rate discharge characteristics, it is preferable that the half-height width of the diffraction peak of the (003) plane is 0.15 or less in the X-ray diffraction pattern attributed to the space group P3 ₁ 12 . And the half-height width of the diffraction peak of the (114) plane is 0.25 or less. The full width at half maximum of the diffraction peak of the (003) plane is preferably 0.14° to 0.15°, and the full width at half maximum of the diffraction peak of the (114) plane is preferably 0.23° to 0.25°.

為了使(003)面的繞射波峰的半高寬為0.15°以下、(114)面的繞射波峰的半高寬為0.25°以下，亦必須提高煅燒溫度。 In order to make the half-height width of the diffraction peak of the (003) plane 0.15° or less and the half-height width of the diffraction peak of the (114) plane to be 0.25° or less, it is necessary to increase the firing temperature.

如上所述，較佳煅燒溫度是根據活性物質的氧釋放溫度而不同，難以一概地設定煅燒溫度的較佳範圍，但若較佳為900℃~1050℃，更佳為920℃~1000℃，則可發揮高的特性。 As described above, the calcination temperature is preferably different depending on the oxygen release temperature of the active material, and it is difficult to set the calcination temperature in a preferred range, but it is preferably 900 ° C to 1050 ° C, more preferably 920 ° C to 1000 ° C, It can play a high level of performance.

繞射波峰的半高寬是由表示晶格的失配程度的變形量、及作為最小域(domain)的微晶(crystallite)尺寸兩 個因素所支配，為了根據半高寬來辨別結晶性程度，必須分別把握。發明者們藉由詳細分析本發明活性物質的半高寬而確認到，於800℃以下的溫度下合成的試樣中，於晶格內殘存變形，藉由在該溫度以上的溫度下合成，可幾乎去除變形。另外，微晶的尺寸與合成溫度的上升成比例地變大。因此，本發明活性物質的組成亦於系內幾乎無格子的變形，且旨在形成微晶尺寸充分成長的粒子，由此可獲得良好的放電電容。具體而言可知，較佳為採用影響晶格常數的變形量為1%以下、且微晶尺寸成長至150nm以上的合成溫度(煅燒溫度)。藉由將該些活性物質成型為電極並進行充放電，亦可見由膨脹收縮引起的變化，充放電過程中亦是微晶尺寸保持130nm以上於所得效果方面而言較佳。即，藉由以儘可能接近上述活性物質的氧釋放溫度的方式選擇煅燒溫度，方可獲得可逆電容明顯大的活性物質。 The full width at half maximum of the diffraction peak is the amount of deformation indicating the degree of mismatch of the crystal lattice, and the crystallite size as the minimum domain. According to one factor, in order to distinguish the degree of crystallinity according to the full width at half maximum, it must be separately grasped. The inventors confirmed by analyzing the full width at half maximum of the active material of the present invention that the sample synthesized at a temperature of 800 ° C or lower was deformed in the crystal lattice and synthesized at a temperature higher than the temperature. The deformation can be almost removed. Further, the size of the crystallites becomes larger in proportion to the increase in the synthesis temperature. Therefore, the composition of the active material of the present invention is also almost free of lattice deformation in the system, and is intended to form particles having a sufficiently grown crystallite size, whereby a good discharge capacity can be obtained. Specifically, it is preferable to use a synthesis temperature (calcination temperature) in which the amount of deformation affecting the lattice constant is 1% or less and the crystallite size is increased to 150 nm or more. By molding the active materials into electrodes and performing charge and discharge, changes due to expansion and contraction are also observed, and it is preferable that the crystallite size is maintained at 130 nm or more in charge and discharge. That is, by selecting the calcination temperature as close as possible to the oxygen release temperature of the above-mentioned active material, an active material having a reversible capacitance significantly large can be obtained.

本發明的鋰二次電池所用的非水電解質並無限定，可使用通常提出用於鋰電池等的非水電解質。非水電解質所用的非水溶劑可列舉：碳酸丙二酯(propylene carbonate)、碳酸乙二酯、碳酸丁二酯、碳酸氯乙二酯(chloroethylene carbonate)、碳酸乙烯酯等的環狀碳酸酯類；γ-丁內酯(γ-butyrolactone)、γ-戊內酯等環狀酯類；碳酸二甲酯、碳酸二乙酯、碳酸酯乙基甲基等的鏈狀碳酸酯類；甲酸甲酯、乙酸甲酯、丁酸甲酯等的鏈狀酯類；四氫呋喃(tetrahydro furan)或其衍生物；1,3-二噁烷(1,3-dioxane)、 1,4-二噁烷、1,2-二甲氧基乙烷(1,2-dimethoxy ethane)、1,4-二丁氧基乙烷、二乙二醇二甲醚(methyl diglyme)等的醚類；乙腈(acetonitrile)、苯甲腈等的腈類；二氧戊環(dioxolane)及其衍生物；環硫乙烷(ethylene sulfide)、環丁碸(sulfolane)、磺內酯(sultone)及其衍生物等的單獨或該些的兩種以上的混合物等，但不限定於該些溶劑。 The nonaqueous electrolyte used in the lithium secondary battery of the present invention is not limited, and a nonaqueous electrolyte generally used for a lithium battery or the like can be used. Examples of the nonaqueous solvent used for the nonaqueous electrolyte include cyclic carbonates such as propylene carbonate, ethylene carbonate, butylene carbonate, chloroethylene carbonate, and ethylene carbonate. a cyclic ester such as γ-butyrolactone or γ-valerolactone; a chain carbonate such as dimethyl carbonate, diethyl carbonate or carbonate methyl group; methyl formate a chain ester of methyl acetate, methyl butyrate or the like; tetrahydrofuran or a derivative thereof; 1,3-dioxane, 1,4-dioxane, 1,2-dimethoxy ethane, 1,4-dibutoxyethane, methyl diglyme, etc. Ethers; acetonitrile, benzonitrile and other nitriles; dioxolane and its derivatives; ethylene sulfide, sulfolane, sultone And a derivative thereof, or the like, or a mixture of two or more of them, but is not limited to the solvents.

非水電解質所用的電解質鹽例如可列舉：LiClO₄、LiBF₄、LiAsF₆、LiPF₆、LiSCN、LiBr、LiI、Li₂SO₄、Li₂B₁₀Cl₁₀、NaClO₄、NaI、NaSCN、NaBr、KClO₄、KSCN等的含有鋰(Li)、鈉(Na)、鉀(K)中的一種的無機離子鹽；LiCF₃SO₃、LiN(CF₃SO₂)₂、LiN(C₂F₅SO₂)₂、LiN(CF₃SO₂)(C₄F₉SO₂)、LiC(CF₃SO₂)₃、LiC(C₂F₅SO₂)₃、(CH₃)₄NBF₄、(CH₃)₄NBr、(C₂H₅)₄NClO₄、(C₂H₅)₄NI、(C₃H₇)₄NBr、(n-C₄H₉)₄NClO₄、(n-C₄H₉)₄NI、順丁烯二酸-(C₂H₅)₄N((C₂H₅)₄N-maleate)、苯甲酸-(C₂H₅)₄N((C₂H₅)₄N-benzoate)、酞酸-(C₂H₅)₄N((C₂H₅)₄N-phthalate)、硬脂基磺酸鋰、辛基磺酸鋰、十二烷基苯磺酸鋰等的有機離子鹽等，該些離子性化合物可單獨使用或混合使用兩種以上。 Examples of the electrolyte salt used for the nonaqueous electrolyte include LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiPF ₆ , LiSCN, LiBr, LiI, Li ₂ SO ₄ , Li ₂ B ₁₀ Cl ₁₀ , NaClO ₄ , NaI, NaSCN, NaBr, An inorganic ion salt containing one of lithium (Li), sodium (Na), and potassium (K) such as KClO ₄ or KSCN; LiCF ₃ SO ₃ , LiN(CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN(CF ₃ SO ₂ )(C ₄ F ₉ SO ₂ ), LiC(CF ₃ SO ₂ ) ₃ , LiC(C ₂ F ₅ SO ₂ ) ₃ , (CH ₃ ) ₄ NBF ₄ , (CH ₃ ) ₄ NBr, (C ₂ H ₅ ) ₄ NClO ₄ , (C ₂ H ₅ ) ₄ NI, (C ₃ H ₇ ) ₄ NBr, (nC ₄ H ₉ ) ₄ NClO ₄ , (nC ₄ H ₉ ) ₄ NI, maleic acid-(C ₂ H ₅ ) ₄ N((C ₂ H ₅ ) ₄ N-maleate), benzoic acid-(C ₂ H ₅ ) ₄ N((C ₂ H ₅ ) ₄ N- Benzoate), phthalic acid-(C ₂ H ₅ ) ₄ N((C ₂ H ₅ ) ₄ N-phthalate), lithium stearyl sulfonate, lithium octyl sulfonate, lithium dodecylbenzene sulfonate, etc. These ionic compounds may be used singly or in combination of two or more kinds.

進而，藉由將LiBF₄與LiN(C₂F₅SO₂)₂之類的具有全氟烷基的鋰鹽混合使用，可進一步降低電解質的黏度，故可進一步提高低溫特性，另外可抑制自放電，更為理想。 Further, by using LiBF _{4 in} combination with a lithium salt having a perfluoroalkyl group such as LiN(C ₂ F ₅ SO ₂ ) ₂ , the viscosity of the electrolyte can be further lowered, so that the low-temperature characteristics can be further improved, and the self-inhibition can be further suppressed. Discharge is more ideal.

另外，亦可使用常溫熔融鹽或離子液體作為非水電解質。 Further, a normal temperature molten salt or an ionic liquid can also be used as the nonaqueous electrolyte.

關於非水電解質中的電解質鹽的濃度，為了可靠地獲得具有高的電池特性的非水電解質電池，較佳為0.1mol/l~5mol/l，更佳為0.5mol/l~2.5mol/l。 Regarding the concentration of the electrolyte salt in the nonaqueous electrolyte, in order to reliably obtain a nonaqueous electrolyte battery having high battery characteristics, it is preferably from 0.1 mol/l to 5 mol/l, more preferably from 0.5 mol/l to 2.5 mol/l. .

負極材料並無限定，只要是可析出或吸藏鋰離子的形態，則可任意選擇。例如可列舉：Li[Li_1/3Ti_5/3]O₄所代表的具有尖晶石型結晶構造的鈦酸鋰等的鈦系材料，Si或Sb、Sn系等的合金系材料鋰金屬，鋰合金(鋰-矽、鋰-鋁、鋰-鉛、鋰-錫、鋰-鋁-錫、鋰-鎵及伍氏易溶合金(Wood's metal)等的含鋰金屬的合金)，鋰複合氧化物(鋰-鈦)，氧化矽，除此之外可列舉：可吸藏‧釋放鋰的合金、碳材料(例如石墨(graphite)、硬碳(hard carbon)、低溫煅燒碳、非晶碳等)等。 The material of the negative electrode is not limited, and may be arbitrarily selected as long as it can precipitate or occlude lithium ions. For example, a titanium-based material such as lithium titanate having a spinel crystal structure represented by Li[Li _1/3 Ti _5/3 ]O ₄ or an alloy material such as Si or Sb or Sn-based material may be mentioned. , lithium alloy (lithium-niobium, lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and lithium metal alloys such as Wood's metal), lithium composite Oxide (lithium-titanium), antimony oxide, and other examples: alloys capable of occluding and releasing lithium, carbon materials (for example, graphite, hard carbon, low-temperature calcined carbon, amorphous carbon) and many more.

正極活性物質的粉體及負極材料的粉體較理想的是平均粒子尺寸為100μm以下。特別是為了提高非水電解質電池的高輸出特性，正極活性物質的粉體較理想的是10μm以下。為了以特定形狀而獲得粉體，可使用粉碎機或分級機。例如可使用研缽、球磨機(ball mill)、砂磨機、振動球磨機、行星式球磨機(planet ball mill)、噴射磨機、反噴磨機(counter jet mill)、渦旋氣流型噴射磨機或篩等。粉碎時，亦可使用共存有水或己烷(hexane)等的有機溶劑的濕式粉碎。分級方法並無特別限定，篩或風力分級機等的乾式、濕式均是視需要而使用。 The powder of the positive electrode active material and the powder of the negative electrode material preferably have an average particle size of 100 μm or less. In particular, in order to improve the high output characteristics of the nonaqueous electrolyte battery, the powder of the positive electrode active material is preferably 10 μm or less. In order to obtain a powder in a specific shape, a pulverizer or a classifier can be used. For example, a mortar, a ball mill, a sand mill, a vibratory ball mill, a planetary ball mill, a jet mill, a counter jet mill, a vortex jet mill or Sieves, etc. At the time of pulverization, wet pulverization in which an organic solvent such as water or hexane is present may be used. The classification method is not particularly limited, and dry or wet types such as a sieve or an air classifier are used as needed.

以上，對作為正極及負極的主要構成成分的正極活性物質及負極材料進行了詳述，上述正極及負極中，除了上 述主要構成成分以外，亦可含有導電劑、結著劑、增黏劑、填料等作為其他構成成分。 The positive electrode active material and the negative electrode material which are main constituent components of the positive electrode and the negative electrode have been described in detail above, and the positive electrode and the negative electrode are excluded from the above. In addition to the main constituent components, a conductive agent, a binder, a tackifier, a filler, or the like may be contained as another constituent component.

導電劑只要是不對電池性能產生不良影響的電子傳導性材料，則並無限定，通常可包括天然石墨(鱗狀石墨、鱗片狀石墨、土狀石墨等)、人造石墨、碳黑(carbon black)、乙炔黑(acetylene black)、科琴黑(Ketjen black)、碳晶鬚(carbon whisker)、碳纖維、金屬(銅、鎳、鋁、銀、金等)粉、金屬纖維、導電性陶瓷材料等的導電性材料的一種或該些的混合物。 The conductive agent is not limited as long as it is an electron conductive material that does not adversely affect the battery performance, and may generally include natural graphite (scaly graphite, flaky graphite, earthy graphite, etc.), artificial graphite, carbon black. , acetylene black, Ketjen black, carbon whisker, carbon fiber, metal (copper, nickel, aluminum, silver, gold, etc.) powder, metal fiber, conductive ceramic material, etc. One or a mixture of conductive materials.

該些中，就電子傳導性及塗佈性的觀點而言，導電劑較理想的是乙炔黑。相對於正極負極的總重量，導電劑的添加量較佳為0.1wt%(重量百分比)~50wt%，特佳為0.5wt%~30wt%。特別是若將乙炔黑粉碎成0.1μm~0.5μm的超微粒子而使用，則可減少需要的碳量，故較理想。該些成分的混合方法為物理混合，理想的是均勻混合。因此，能以乾式或濕式將V型混合機、S型混合機、擂潰機、球磨機、行星式球磨機之類的粉體混合機混合。 Among these, from the viewpoint of electron conductivity and coatability, the conductive agent is preferably acetylene black. The amount of the conductive agent added is preferably from 0.1% by weight to 50% by weight, particularly preferably from 0.5% by weight to 30% by weight based on the total weight of the positive electrode and the negative electrode. In particular, when acetylene black is pulverized into ultrafine particles of 0.1 μm to 0.5 μm, the amount of carbon required can be reduced, which is preferable. The mixing method of the ingredients is physical mixing, and it is desirable to uniformly mix. Therefore, it is possible to mix a powder mixer such as a V-type mixer, an S-type mixer, a crusher, a ball mill, or a planetary ball mill in a dry or wet manner.

上述結著劑通常可使用聚四氟乙烯(polytetrafluoroethylene，PTFE)、聚偏二氟乙烯(polyvinylidene difluoride，PVDF)、聚乙烯、聚丙烯等的熱塑性樹脂，乙烯-丙烯-二烯三元共聚物(ethylene-propylene-diene terpolymer，EPDM)、磺化EPDM、苯乙烯丁二烯橡膠(styrene-butadiene rubber，SBR)、氟橡膠等的具有橡膠彈性的聚合物的一種或兩種以 上的混合物。相對於正極負極的總重量，結著劑的添加量較佳為1wt%~50wt%，特佳為2wt%~30wt%。 As the above-mentioned binder, a thermoplastic resin such as polytetrafluoroethylene (PTFE), polyvinylidene difluoride (PVDF), polyethylene or polypropylene, or an ethylene-propylene-diene terpolymer ( One or two of rubber-elastic polymers such as ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluororubber, etc. The mixture on it. The amount of the binder added is preferably from 1% by weight to 50% by weight, particularly preferably from 2% by weight to 30% by weight based on the total weight of the positive electrode and the negative electrode.

填料只要為不對電池性能造成不良影響的材料，則可為任意材料。通常可使用聚丙烯、聚乙烯等的烯烴系聚合物，非晶形二氧化矽、氧化鋁、沸石、玻璃、碳等。關於填料的添加量，相對於正極負極的總重量，添加量較佳為30wt%以下。 The filler may be any material as long as it does not adversely affect the battery performance. Generally, an olefin-based polymer such as polypropylene or polyethylene, amorphous cerium oxide, aluminum oxide, zeolite, glass, carbon or the like can be used. The addition amount of the filler is preferably 30% by weight or less based on the total weight of the positive electrode negative electrode.

正極及負極是藉由以下方式而合適地製作：將上述主要構成成分(正極為正極活性物質，負極為負極材料)及其他材料混練成合劑，混合至N-甲基吡咯烷酮(N-methyl-pyrrolidinone)、甲苯(toluene)等的有機溶劑中後，將所得的混合液塗佈於下文將詳述的集電體上，進行壓接並於50℃~250℃左右的溫度下進行2小時左右的加熱處理。上述塗佈方法例如較理想的是使用敷料輥(applicator roll)等的輥塗佈、網版塗佈(screen coating)、刮刀(doctor blade)方式、旋轉塗佈(spin coating)、棒塗機(bar coater)等的手段塗佈成任意的厚度及任意的形狀，但不限定於此。 The positive electrode and the negative electrode are suitably produced by kneading the above-mentioned main constituent components (the positive electrode is a positive electrode active material and the negative electrode as a negative electrode material) and other materials into a mixture, and mixing it with N-methyl-pyrrolidinone (N-methyl-pyrrolidinone) After the organic solvent such as toluene or the like, the obtained mixed solution is applied to a current collector which will be described later in detail, and is pressure-bonded at a temperature of about 50 ° C to 250 ° C for about 2 hours. Heat treatment. The above coating method is preferably, for example, roll coating, screen coating, doctor blade method, spin coating, bar coater using an applicator roll or the like ( The means such as bar coater) is applied to any thickness and arbitrary shape, but is not limited thereto.

隔離膜(separator)較佳為將表現出優異的高率放電性能的多孔膜或不織布等單獨或併用。構成非水電解質電池用隔離膜的材料例如可列舉：聚乙烯、聚丙烯等所代表的聚烯烴系樹脂，聚對苯二甲酸乙二酯、聚對苯二甲酸丁二酯等所代表的聚酯系樹脂，聚偏二氟乙烯、偏二氟乙烯-六氟丙烯共聚物、偏二氟乙烯-全氟乙烯基醚共聚物、偏二 氟乙烯-四氟乙烯共聚物、偏二氟乙烯-三氟乙烯共聚物、偏二氟乙烯-氟乙烯共聚物、偏二氟乙烯-六氟丙酮共聚物、偏二氟乙烯-乙烯共聚物、偏二氟乙烯-丙烯共聚物、偏二氟乙烯-三氟丙烯共聚物、偏二氟乙烯-四氟乙烯-六氟丙烯共聚物、偏二氟乙烯-乙烯-四氟乙烯共聚物等。 The separator is preferably used alone or in combination with a porous film or a nonwoven fabric exhibiting excellent high rate discharge performance. The material constituting the separator for a non-aqueous electrolyte battery is, for example, a polyolefin resin represented by polyethylene or polypropylene, or a polymer represented by polyethylene terephthalate or polybutylene terephthalate. Ester resin, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-perfluorovinyl ether copolymer, partial a vinyl fluoride-tetrafluoroethylene copolymer, a vinylidene fluoride-trifluoroethylene copolymer, a vinylidene fluoride-fluoroethylene copolymer, a vinylidene fluoride-hexafluoroacetone copolymer, a vinylidene fluoride-ethylene copolymer, A vinylidene fluoride-propylene copolymer, a vinylidene fluoride-trifluoropropene copolymer, a vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer, a vinylidene fluoride-ethylene-tetrafluoroethylene copolymer, or the like.

隔離膜的空孔率就強度的觀點而言較佳為98vol%(體積百分比)以下。另外，就充放電特性的觀點而言，空孔率較佳為20vol%以上。 The porosity of the separator is preferably 98 vol% or less from the viewpoint of strength. Further, from the viewpoint of charge and discharge characteristics, the porosity is preferably 20 vol% or more.

另外，隔離膜例如亦可使用由丙烯腈、環氧乙烷(ethylene oxide)、環氧丙烷、甲基丙烯酸甲酯、乙酸乙烯酯(vinyl acetate)、乙烯基吡咯烷酮、聚偏二氟乙烯等的聚合物與電解質構成的聚合物凝膠。若如上述般以凝膠狀態而使用非水電解質，則就有防止漏液的效果方面而言較佳。 Further, as the separator, for example, acrylonitrile, ethylene oxide, propylene oxide, methyl methacrylate, vinyl acetate, vinyl pyrrolidone, polyvinylidene fluoride or the like may be used. A polymer gel composed of a polymer and an electrolyte. When a nonaqueous electrolyte is used in a gel state as described above, it is preferable in terms of an effect of preventing liquid leakage.

進而，隔離膜若將如上所述的多孔膜或不織布等與聚合物凝膠併用而使用，則電解質的保液性提高，故較為理想。即，藉由形成在聚乙烯微孔膜的表面及微孔壁面包覆厚度數μm以下的親溶劑性聚合物的薄膜，將電解質保持於上述薄膜的微孔內，則上述親溶劑性聚合物形成凝膠。 Further, when the separator is used in combination with a polymer gel as described above, the porous film or the nonwoven fabric is preferably used in combination with the polymer gel. That is, by forming a film of a solvophilic polymer having a thickness of several μm or less on the surface of the polyethylene microporous film and the surface of the microporous membrane, and maintaining the electrolyte in the pores of the film, the solvophilic polymer A gel is formed.

上述親溶劑性聚合物除了聚偏二氟乙烯以外，可列舉具有環氧乙烷基或酯基等的丙烯酸酯單體、環氧單體、具有異氰酸酯基的單體等交聯而成的聚合物等。該單體可併用自由基起始劑而使用加熱或紫外線(UV)，或使用電子束(EB)等的活性光線等來進行交聯反應。 In addition to polyvinylidene fluoride, the solvophilic polymer may be a polymer obtained by crosslinking an acrylate monomer such as an oxiranyl group or an ester group, an epoxy monomer, or a monomer having an isocyanate group. Things and so on. The monomer may be subjected to a crosslinking reaction using heat or ultraviolet rays (UV) in combination with a radical initiator, or using an active light such as an electron beam (EB).

鋰二次電池的構成並無特別限定，具有正極、負極及輥狀隔離膜的圓筒型電池、方型電池、扁平型電池等可列舉作一例。 The configuration of the lithium secondary battery is not particularly limited, and a cylindrical battery, a square battery, a flat battery, or the like having a positive electrode, a negative electrode, and a roll-shaped separator can be exemplified.

[實例1] [Example 1]

(實例1-1) (Example 1-1)

將硫酸錳五水合物、硫酸鎳六水合物、硫酸鈷七水合物及硫酸鎂七水合物以Co、Ni、Mn、Mg各元素成為12.5：17.438：68.75：1.312的比率的方式溶解於離子交換水中而製作混合水溶液。此時，使其合計濃度為0.667mol/l，體積為180ml。繼而，於1L(升)的燒杯(beaker)中準備600ml的離子交換水，使用熱水浴保持於50℃，滴加8N的NaOH，藉此將pH值調整為12.0。於該狀態下使氬氣(Ar)鼓泡30min，將溶液內的溶存氧充分去除。以轉速700rpm對燒杯內進行攪拌，以3ml/min的速度滴加上述硫酸鹽的混合水溶液。其間，使用熱水浴將溫度保持於一定，並間斷地滴加8N的NaOH，藉此將pH值保持於一定。同時，以0.83ml/min的速度滴加作為還原劑的濃度為2.0mol/l的肼(hydrazine)水溶液50ml。兩者滴加結束後，於停止攪拌的狀態下靜止12h以上，使共沈澱氫氧化物充分進行粒子成長。 The manganese sulfate pentahydrate, the nickel sulfate hexahydrate, the cobalt sulfate heptahydrate, and the magnesium sulfate heptahydrate are dissolved in the ion exchange so that the elements of Co, Ni, Mn, and Mg become a ratio of 12.5:17.438:68.75:1.312. A mixed aqueous solution was prepared in water. At this time, the total concentration was 0.667 mol/l, and the volume was 180 ml. Then, 600 ml of ion-exchanged water was prepared in a 1 L (liter) beaker, and maintained at 50 ° C using a hot water bath, and 8 N of NaOH was added dropwise thereto to adjust the pH to 12.0. Argon gas (Ar) was bubbled in this state for 30 minutes, and the dissolved oxygen in the solution was sufficiently removed. The inside of the beaker was stirred at a number of revolutions of 700 rpm, and the mixed aqueous solution of the above sulfate was added dropwise at a rate of 3 ml/min. In the meantime, the temperature was kept constant using a hot water bath, and 8 N NaOH was intermittently added dropwise, thereby keeping the pH constant. At the same time, 50 ml of a hydrazine aqueous solution having a concentration of 2.0 mol/l as a reducing agent was added dropwise at a rate of 0.83 ml/min. After the completion of the dropwise addition, the mixture was allowed to stand still for 12 hours or more while the stirring was stopped, and the coprecipitated hydroxide was sufficiently grown.

再者，上述順序中若各溶液的滴加速度過快，則無法以元素水準獲得均勻的前驅物。例如於將滴加速度設定為上述速度的10倍時，前驅物中的元素分布明顯變得不均勻。另外，於使用此種不均勻的前驅物合成活性物質時， 煅燒後的元素的分布亦變得不均勻，無法發揮充分的電極特性。附帶而言，於藉由固相法使用LiOH‧H₂O、Co(OH)₂、Ni(OH)₂、MnOOH、Mg(OH)₂作為原料粉體時，則更不均勻，故欠佳。 Further, in the above procedure, if the dropping rate of each solution is too fast, a uniform precursor cannot be obtained at the elemental level. For example, when the drop acceleration is set to 10 times the above speed, the element distribution in the precursor becomes significantly uneven. Further, when the active material is synthesized using such a non-uniform precursor, the distribution of the elements after the firing is also uneven, and sufficient electrode characteristics cannot be exhibited. Incidentally, when LiOH‧H ₂ O, Co(OH) ₂ , Ni(OH) ₂ , MnOOH, or Mg(OH) _{2 is} used as a raw material powder by a solid phase method, it is more uneven, so it is not preferable. .

繼而，藉由抽氣過濾取出共沈澱產物，於空氣環境中、常壓下利用烘箱於100℃下乾燥。乾燥後以使粒徑一致的方式利用直徑約為120mmφ的研缽粉碎數分鐘，獲得乾燥粉末。 Then, the coprecipitated product was taken out by suction filtration, and dried at 100 ° C in an air atmosphere under normal pressure using an oven. After drying, it was pulverized in a mortar having a diameter of about 120 mmφ for several minutes so as to have a uniform particle diameter to obtain a dry powder.

藉由X射線繞射測定確認到，該乾燥粉末為β-Ni(OH)₂型的單相。另外，藉由EPMA測定確認到Co、Ni、Mn均勻地分布。 It was confirmed by X-ray diffraction measurement that the dry powder was a single phase of the β-Ni(OH) ₂ type. Further, it was confirmed by EPMA measurement that Co, Ni, and Mn were uniformly distributed.

以相對於金屬元素(Ni+Mn+Co+Mg)的Li量滿足表1的實例1-1的組成式的方式稱量氫氧化鋰一水合物粉末(LiOH‧H₂O)，進行混合而獲得混合粉體。 Lithium hydroxide monohydrate powder (LiOH‧H ₂ O) was weighed in such a manner that the amount of Li of the metal element (Ni+Mn+Co+Mg) satisfies the composition formula of Example 1-1 of Table 1 and was mixed. A mixed powder is obtained.

繼而，以6MPa的壓力對混合粉體進行顆粒(pellet)成型。供於顆粒成型的前驅物粉末的量是以合成後的產物的重量為3g的方式換算而確定。結果，成型後的顆粒的直徑為25mmφ，厚度為約10mm~12mm。將上述顆粒載置於全長為約100mm的氧化鋁製舟(boat)中，放入至箱型電氣爐中，於空氣環境中、常壓下於1000℃下煅燒12h。上述箱型電氣爐的內部尺寸為縱向10cm、寬度20cm、深度30cm，於寬度方向20cm間隔間放入電熱線。煅燒後，切斷加熱器的開關，保持將氧化鋁製舟置於爐內的狀態而自然放置冷卻。結果，爐的溫度於5小時後下降至約 200℃左右，其後的降溫速度稍慢。經過一晝夜後，確認到爐的溫度為100℃以下，然後取出顆粒，使用研缽而粉碎成粒徑一致的程度。 Then, the mixed powder was subjected to pellet molding at a pressure of 6 MPa. The amount of the precursor powder supplied to the pellets was determined in such a manner that the weight of the synthesized product was 3 g. As a result, the formed pellets had a diameter of 25 mmφ and a thickness of about 10 mm to 12 mm. The pellets were placed in an alumina boat having a total length of about 100 mm, placed in a box-type electric furnace, and calcined at 1000 ° C for 12 hours in an air atmosphere at normal pressure. The internal dimensions of the box-type electric furnace were 10 cm in the longitudinal direction, 20 cm in width, and 30 cm in depth, and electric heating wires were placed between the intervals of 20 cm in the width direction. After the calcination, the switch of the heater was turned off, and the alumina boat was placed in the furnace to be naturally placed and cooled. As a result, the temperature of the furnace drops to about 5 hours later. At about 200 ° C, the subsequent cooling rate is slightly slower. After a day and night, it was confirmed that the temperature of the furnace was 100 ° C or less, and then the pellets were taken out and pulverized to a uniform particle size using a mortar.

關於所得的活性物質，其組成為Li_1.2Co_0.1Ni_0.139Mg_0.011Mn_0.55O₂，關於其結晶構造，使用Cu(Kα)管球的粉末X射線繞射測定的結果為，確認到α-NaFeO₂型的六方晶構造為主相，並且部分觀察到Li[Li_1/3Mn_2/3]O₂型的單斜晶中可見的20°~30°附近的繞射波峰。對該些所有的繞射線藉由Rietveld法進行結晶構造分析，結果與歸屬於空間群P3₁12的結晶構造模型非常一致。 With respect to the obtained active material, the composition was Li _1.2 Co _0.1 Ni _0.139 Mg _0.011 Mn _0.55 O ₂ , and as a result of measurement of the crystal structure of the Cu(Kα) bulb by powder X-ray diffraction, α-NaFeO was confirmed. _The type ₂ hexagonal crystal structure is the main phase, and a diffraction peak near 20° to 30° visible in the monoclinic crystal of the Li[Li _1/3 Mn _2/3 ]O ₂ type is partially observed. The crystal structure analysis of all the diffraction rays by the Rietveld method is very consistent with the crystal structure model attributed to the space group P3 ₁ 12 .

根據2θ：18.6±1°時的繞射波峰求出(003)面的繞射波峰的面積，根據2θ：44.1±1°時的繞射波峰求出(114)面的繞射波峰的面積，算出兩繞射波峰的強度比(面積比)I₍₀₀₃₎/I₍₁₁₄₎，結果為1.41。 The area of the diffraction peak of the (003) plane is obtained from the diffraction peak at 2θ: 18.6±1°, and the area of the diffraction peak of the (114) plane is obtained from the diffraction peak at 2θ: 44.1±1°. The intensity ratio (area ratio) I ₍₀₀₃₎ / I _{(114) of the} two diffraction peaks was calculated, and the result was 1.41.

再者，所謂「波峰強度」，是指X射線檢測器對X射線量進行計數所得的數值的累計值，故於X射線繞射圖中出現的波峰中，相當於「面積」。其中，於所比較的波峰的寬度無差異或波峰的寬度非常窄時，只要比較波峰的高度即可，此處不僅比較波峰的高度，而且比較面積。 In addition, the "crest intensity" refers to the integrated value of the numerical value obtained by the X-ray detector counting the X-ray amount, and therefore corresponds to the "area" in the peak appearing in the X-ray diffraction pattern. However, when there is no difference in the width of the peaks to be compared or the width of the peaks is very narrow, it is only necessary to compare the heights of the peaks, and here, not only the heights of the peaks but also the areas are compared.

另外，根據2θ：18.6±1°時的繞射波峰求出(003)面的繞射波峰的半高寬，結果為0.14°，根據2θ：44.1±1°時的繞射波峰求出(114)面的繞射波峰的半高寬，結果為0.23°。 Further, the full width at half maximum of the diffraction peak of the (003) plane was obtained from the diffraction peak at 2θ: 18.6±1°, and found to be 0.14°, which was obtained from the diffraction peak at 2θ: 44.1±1° (114). The full width at half maximum of the diffraction peak of the face is 0.23°.

進而，於電腦(computer)上對X射線繞射圖形的資料進行Rietveld分析，該分析過程中，使高斯函數及勞倫茲函數所含的結晶參數精密化，根據如此而求出的結晶參數，分別計算晶格變形及微晶尺寸，結果微晶尺寸為180nm。 Further, Rietveld analysis is performed on the data of the X-ray diffraction pattern on a computer, in which the crystallization parameters contained in the Gaussian function and the Lorentz function are refined, and the crystallization parameters obtained according to the above are The lattice deformation and crystallite size were calculated separately, and the crystallite size was 180 nm.

(實例1-2~實例1-5) (Example 1-2~Example 1-5)

除了變更為表1的實例1-2~實例1-5所示的煅燒溫度(980℃、960℃、940℃、920℃)以外，與實例1-1同樣地合成本發明的活性物質。 The active material of the present invention was synthesized in the same manner as in Example 1-1, except that the calcination temperatures (980 ° C, 960 ° C, 940 ° C, and 920 ° C) shown in Examples 1-2 to 1-5 of Table 1 were changed.

X射線繞射測定的結果與實例1-1相同，確認到α-NaFeO₂型的六方晶構造為主相，並且部分地觀察到Li[Li_1/3Mn_2/3]O₂型的單斜晶中可見的20°~30°附近的繞射波峰。對該些所有的繞射線藉由Rietveld法進行結晶構造分析，結果與歸屬於空間群P3₁12的結晶構造模型非常一致。 The results of the X-ray diffraction measurement were the same as in Example 1-1, and it was confirmed that the hexagonal crystal structure of the α-NaFeO ₂ type was the main phase, and the Li[Li _1/3 Mn _2/3 ]O ₂ type was partially observed. Diffraction peaks around 20°~30° visible in the slant crystal. The crystal structure analysis of all the diffraction rays by the Rietveld method is very consistent with the crystal structure model attributed to the space group P3 ₁ 12 .

與實例1-1同樣地算出繞射波峰的強度比(面積比)I₍₀₀₃₎/I₍₁₁₄₎，結果為1.15~1.35。 In the same manner as in Example 1-1, the intensity ratio (area ratio) I ₍₀₀₃₎ / I _{(114) of the} diffraction peak was calculated, and as a result, it was 1.15 to 1.35.

(比較例1-1~比較例1-5) (Comparative Example 1-1 to Comparative Example 1-5)

除了變更為表1的比較例1-1~比較例1-5所示的煅燒溫度(900℃、800℃、700℃、550℃、1100℃)以外，與實例1-1同樣地合成比較例的活性物質。 A comparative example was synthesized in the same manner as in Example 1-1 except that the firing temperatures (900 ° C, 800 ° C, 700 ° C, 550 ° C, and 1100 ° C) shown in Comparative Example 1-1 to Comparative Example 1-5 of Table 1 were changed. Active substance.

對於比較例1-1~比較例1-4，與實例1-1同樣地進行結晶構造分析，結果確認到可歸屬於空間群P3₁12的X射線繞射圖案。 In Comparative Example 1-1 to Comparative Example 1-4, crystal structure analysis was carried out in the same manner as in Example 1-1, and as a result, an X-ray diffraction pattern attributable to the space group P3 ₁ 12 was confirmed.

關於比較例1-5，空間群為C2/m，與P3₁12不同。 Regarding Comparative Example 1-5, the space group is C2/m, which is different from P3 ₁ 12 .

與實例1-1同樣地算出繞射波峰的強度比(面積比)I₍₀₀₃₎/I₍₁₁₄₎，結果為0.95~1.13。 In the same manner as in Example 1-1, the intensity ratio (area ratio) I ₍₀₀₃₎ / I _{(114) of the} diffraction peak was calculated, and as a result, it was 0.95 to 1.13.

(實例1-6~實例1-9) (Example 1-6 ~ Example 1-9)

關於共沈澱氫氧化物前驅物所含有的金屬元素的組成及氫氧化鋰一水合物的混合量，按表1的實例1-6~實例1-9所示的組成式進行變更，除此以外，與實例1-1同樣地合成本發明的活性物質。 The composition of the metal element contained in the coprecipitated hydroxide precursor and the amount of lithium hydroxide monohydrate mixed are changed according to the composition formulas shown in Examples 1-6 to 1-9 of Table 1, and The active material of the present invention was synthesized in the same manner as in Example 1-1.

與實例1-1同樣地進行結晶構造分析，結果確認到可歸屬於空間群P3₁12的X射線繞射圖案。 The crystal structure analysis was carried out in the same manner as in Example 1-1, and as a result, the X-ray diffraction pattern attributable to the space group P3 ₁ 12 was confirmed.

另外，算出繞射波峰的強度比(面積比)I₍₀₀₃₎/I₍₁₁₄₎，結果為1.35~1.51。 Further, the intensity ratio (area ratio) I ₍₀₀₃₎ / I _{(114) of the} diffraction peak was calculated, and as a result, it was 1.35 to 1.51.

(比較例1-6~比較例1-9) (Comparative Example 1-6 to Comparative Example 1-9)

比較例1-6~比較例1-9的活性物質是設定為與實例1-6~實例1-9分別相同的固溶體的組成，並將煅燒溫度變更為800℃，除此以外，與實例1-1同樣地合成。 The active materials of Comparative Example 1-6 to Comparative Example 1-9 were set to have the same solid solution as those of Examples 1-6 to 1-9, and the calcination temperature was changed to 800 ° C, in addition to Example 1-1 was synthesized in the same manner.

與實例1-1同樣地進行結晶構造分析，結果確認到可歸屬於空間群P3₁12的X射線繞射圖案。 The crystal structure analysis was carried out in the same manner as in Example 1-1, and as a result, the X-ray diffraction pattern attributable to the space group P3 ₁ 12 was confirmed.

另外，算出繞射波峰的強度比(面積比)I₍₀₀₃₎/I₍₁₁₄₎，結果為1.12~1.13。 Further, the intensity ratio (area ratio) I ₍₀₀₃₎ / I _{(114) of the} diffraction peak was calculated, and as a result, it was 1.12 to 1.13.

(比較例1-10~比較例1-15) (Comparative Example 1-10 to Comparative Example 1-15)

自共沈澱氫氧化物前驅物所含有的金屬元素中去掉Mg，而將組成變更為Li_1.2Co_0.1Ni_0.15Mn_0.55O₂，並變更為表1的比較例1-10~比較例1-15所示的煅燒溫度(1000℃、 900℃、800℃、700℃、550℃、1100℃)，除此以外，與實例1-1同樣地合成比較例的活性物質。 The Mg was removed from the metal element contained in the coprecipitated hydroxide precursor, and the composition was changed to Li _1.2 Co _0.1 Ni _0.15 Mn _0.55 O ₂ and changed to Comparative Example 1-10 to Comparative Example 1-15 of Table 1. The active material of the comparative example was synthesized in the same manner as in Example 1-1, except that the calcination temperatures (1000 ° C, 900 ° C, 800 ° C, 700 ° C, 550 ° C, and 1100 ° C) were shown.

對於比較例1-10~比較例1-14，與實例1-1同樣地進行結晶構造分析，結果確認到可歸屬於空間群P3₁12的X射線繞射圖案。 In Comparative Example 1-10 to Comparative Example 1-14, the crystal structure analysis was carried out in the same manner as in Example 1-1, and as a result, the X-ray diffraction pattern attributable to the space group P3 ₁ 12 was confirmed.

關於比較例1-15，空間群為C2/m，與P3₁12不同。 Regarding Comparative Example 1-15, the space group is C2/m, which is different from P3 ₁ 12 .

與實例1-1同樣地算出繞射波峰的強度比(面積比)I₍₀₀₃₎/I₍₁₁₄₎，結果為0.94~1.422。 In the same manner as in Example 1-1, the intensity ratio (area ratio) I ₍₀₀₃₎ / I _{(114) of the} diffraction peak was calculated, and as a result, it was 0.94 to 1.422.

(比較例1-16) (Comparative Example 1-16)

為了與本發明的物質比較作為活性物質的特性，而合成含有Al來代替Mg的固溶體Li_1.2Co_0.1Ni_0.144Al_0.012Mn_0.544O₂。 In order to compare the properties of the active material with the substance of the present invention, a solid solution containing Li is substituted for Mg, Li _1.2 Co _0.1 Ni _0.144 Al _0.012 Mn _0.544 O ₂ .

將硫酸錳五水合物、硫酸鎳六水合物及硫酸鈷七水合物以Co、Ni、Mn各元素成為12.69：18.28：69.03的比率的方式溶解於離子交換水中而製作混合水溶液。此時，使其合計濃度為0.667mol/l，體積為180ml。繼而，於1L的燒杯中準備600ml的離子交換水，使用熱水浴保持於50℃，滴加8N的NaOH，藉此將pH值調整為12.0。於該狀態下使氬氣鼓泡30min，將溶液內的溶存氧充分去除。以轉速700rpm對燒杯內進行攪拌，以3ml/min的速度滴加上述硫酸鹽的混合水溶液。其間，使用熱水浴將溫度保持於一定，並間斷地滴加8N的NaOH，藉此將pH值保持於一定。同時，以0.83ml/min的速度滴加作為還原劑的濃度為2.0mol/l的肼水溶液50ml。兩者滴加結束後，於停 止攪拌的狀態下靜止12h以上，藉此使共沈澱氫氧化物充分進行粒子成長。 Manganese sulfate pentahydrate, nickel sulfate hexahydrate, and cobalt sulfate heptahydrate were dissolved in ion-exchange water so that the respective elements of Co, Ni, and Mn became a ratio of 12.69:18.28:69.03 to prepare a mixed aqueous solution. At this time, the total concentration was 0.667 mol/l, and the volume was 180 ml. Then, 600 ml of ion-exchanged water was prepared in a 1 L beaker, kept at 50 ° C using a hot water bath, and 8 N NaOH was added dropwise thereto to adjust the pH to 12.0. Argon gas was bubbled in this state for 30 minutes, and the dissolved oxygen in the solution was sufficiently removed. The inside of the beaker was stirred at a number of revolutions of 700 rpm, and the mixed aqueous solution of the above sulfate was added dropwise at a rate of 3 ml/min. In the meantime, the temperature was kept constant using a hot water bath, and 8 N NaOH was intermittently added dropwise, thereby keeping the pH constant. At the same time, 50 ml of a hydrazine aqueous solution having a concentration of 2.0 mol/l as a reducing agent was added dropwise at a rate of 0.83 ml/min. After the end of the two drops, stop In the state of stirring, the mixture was allowed to stand still for 12 hours or more, whereby the coprecipitated hydroxide was sufficiently grown in the particles.

繼而，藉由抽氣過濾而取出共沈澱產物，於空氣環境中、常壓下利用烘箱於100℃下乾燥。乾燥後，以使粒徑一致的方式利用直徑為約120mmφ的研缽粉碎數分鐘，獲得乾燥粉末。 Then, the coprecipitated product was taken out by suction filtration, and dried at 100 ° C in an air atmosphere under normal pressure using an oven. After drying, it was pulverized in a mortar having a diameter of about 120 mmφ for several minutes so that the particle diameters were uniform to obtain a dry powder.

以滿足表1的比較例1-16的組成式的方式稱量氫氧化鋰一水合物粉末(LiOH‧H₂O)及氫氧化鋁，進行混合而獲得混合粉體。 Lithium hydroxide monohydrate powder (LiOH‧H ₂ O) and aluminum hydroxide were weighed so as to satisfy the composition formula of Comparative Example 1-16 of Table 1, and mixed to obtain a mixed powder.

接著，於6MPa的壓力下對混合粉體進行顆粒成型。供於顆粒成型的前驅物粉末的量是以合成後的產物的重量為3g的方式換算而確定。結果，成型後的顆粒為直徑25mmφ、厚度約10mm~12mm。將上述顆粒載置於全長為約100mm的氧化鋁製舟中，放入至箱型電氣爐中，於空氣環境中、常壓下於1000℃下煅燒12h。上述箱型電氣爐的內部尺寸為縱向10cm、寬度20cm、深度30cm，於寬度方向20cm間隔間放入電熱線。煅燒後，切斷加熱器的開關，保持將氧化鋁製舟置於爐內的狀態自然放置冷卻。結果，爐的溫度於5小時後下降至約200℃左右，其後的降溫速度稍慢。經過一晝夜後，確認到爐的溫度變為100℃以下，然後取出顆粒，使用研缽粉碎成粒徑一致的程度。 Next, the mixed powder was subjected to pellet molding under a pressure of 6 MPa. The amount of the precursor powder supplied to the pellets was determined in such a manner that the weight of the synthesized product was 3 g. As a result, the pellet after molding had a diameter of 25 mmφ and a thickness of about 10 mm to 12 mm. The pellets were placed in an alumina boat having a total length of about 100 mm, placed in a box-type electric furnace, and calcined at 1000 ° C for 12 hours in an air atmosphere at normal pressure. The internal dimensions of the box-type electric furnace were 10 cm in the longitudinal direction, 20 cm in width, and 30 cm in depth, and electric heating wires were placed between the intervals of 20 cm in the width direction. After the calcination, the switch of the heater was turned off, and the state in which the alumina boat was placed in the furnace was naturally placed and cooled. As a result, the temperature of the furnace dropped to about 200 ° C after 5 hours, and the subsequent temperature drop rate was slightly slower. After a day and night, it was confirmed that the temperature of the furnace became 100 ° C or less, and then the pellet was taken out and pulverized to a uniform particle size using a mortar.

關於所得的活性物質，其組成為Li_1.2Co_0.1Ni_0.144Al_0.012Mn_0.544O₂，關於其結晶構造，使用Cu(Kα)管球的粉末X射線繞射測定的結果為，觀察到 α-NaFeO₂型的六方晶構造為主相。對該些所有的繞射線藉由Rietveld法進行結晶構造分析，結果與歸屬於空間群P3₁12的結晶構造模型非常一致。 With respect to the obtained active material, the composition was Li _1.2 Co _0.1 Ni _0.144 Al _0.012 Mn _0.544 O ₂ , and as a result of the powder X-ray diffraction measurement using Cu (Kα) spheres, the α-NaFeO was observed. _The type ₂ hexagonal crystal structure is the main phase. The crystal structure analysis of all the diffraction rays by the Rietveld method is very consistent with the crystal structure model attributed to the space group P3 ₁ 12 .

(比較例1-17) (Comparative Example 1-17)

為了與本發明的物質比較作為活性物質的特性，而合成含有Al代替Mg的固溶體Li_1.2Co_0.1Ni_0.1395Al_0.021Mn_0.5395O₂。 In order to compare the properties of the active material with the substance of the present invention, a solid solution Li _1.2 Co _0.1 Ni _0.1395 Al _0.021 Mn _0.5395 O ₂ containing Al instead of Mg was synthesized.

對於共沈澱氫氧化物前驅物所含有的過渡金屬元素的組成以及氫氧化鋰一水合物及氫氧化鋁的混合量，按表1的比較例1-17所示的組成式進行變更，除此以外，與比較例1-16同樣地合成比較例的活性物質。 The composition of the transition metal element contained in the coprecipitated hydroxide precursor and the mixing amount of lithium hydroxide monohydrate and aluminum hydroxide were changed according to the composition formula shown in Comparative Example 1-17 of Table 1. The active material of the comparative example was synthesized in the same manner as in Comparative Example 1-16.

(比較例1-18) (Comparative Example 1-18)

為了與本發明的物質比較作為活性物質的特性，而合成含有Ti代替Mg的固溶體Li_1.2Co_0.1Ni_0.15Ti_0.03Mn_0.52O₂。 In order to compare the properties of the active material with the substance of the present invention, a solid solution Li _1.2 Co _0.1 Ni _0.15 Ti _0.03 Mn _0.52 O ₂ containing Ti instead of Mg was synthesized.

關於共沈澱氫氧化物前驅物所含有的過渡金屬元素的組成以及氫氧化鋰一水合物及二氧化鈦的混合量，按表1的比較例1-18所示的組成式般進行變更，除此以外，與比較例1-16同樣地合成比較例的活性物質。 The composition of the transition metal element contained in the coprecipitated hydroxide precursor and the mixing amount of lithium hydroxide monohydrate and titanium oxide were changed in accordance with the composition formula shown in Comparative Example 1-18 of Table 1, and The active material of the comparative example was synthesized in the same manner as in Comparative Example 1-16.

(比較例1-19) (Comparative Example 1-19)

為了與本發明的物質比較作為活性物質的特性，而合成含有Ti代替Mg的固溶體Li_1.2Co_0.1Ni_0.15Ti_0.05Mn_0.5O₂。 In order to compare the properties of the active material with the substance of the present invention, a solid solution Li _1.2 Co _0.1 Ni _0.15 Ti _0.05 Mn _0.5 O ₂ containing Ti instead of Mg was synthesized.

關於共沈澱氫氧化物前驅物所含有的過渡金屬元素的組成以及氫氧化鋰一水合物及二氧化鈦的混合量，按表1的比較例1-19所示的組成式進行變更，除此以外，與比較 例1-16同樣地合成比較例的活性物質。 The composition of the transition metal element contained in the coprecipitated hydroxide precursor and the mixing amount of lithium hydroxide monohydrate and titanium oxide were changed according to the composition formula shown in Comparative Example 1-19 of Table 1, and And comparison The active material of the comparative example was synthesized in the same manner as in Example 1-16.

(鋰二次電池的製作及評價) (Production and evaluation of lithium secondary battery)

使用實例1-1~實例1-9及比較例1-1~比較例1-19的各活性物質作為鋰二次電池用正極活性物質，按以下順序製作鋰二次電池，評價電池特性。 Using each of the active materials of Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-19 as a positive electrode active material for a lithium secondary battery, a lithium secondary battery was produced in the following procedure, and battery characteristics were evaluated.

將活性物質、乙炔黑(AB)及聚偏二氟乙烯(PVdF)以重量比85：8：7的比例混合，添加作為分散介質的N-甲基吡咯烷酮進行混練分散，製備塗佈液。再者，PVdF是利用使固體成分溶解分散的溶液，並進行固體重量換算。將該塗佈液塗佈於厚度為20μm的鋁箔集電體上，製作正極板。再者，所有電池是以成為同樣的試驗條件的方式將電極重量、厚度統一。 The active material, acetylene black (AB) and polyvinylidene fluoride (PVdF) were mixed at a weight ratio of 85:8:7, and N-methylpyrrolidone as a dispersion medium was added and kneaded and dispersed to prepare a coating liquid. Further, PVdF is a solution in which solid components are dissolved and dispersed, and solid weight conversion is performed. This coating liquid was applied onto an aluminum foil current collector having a thickness of 20 μm to prepare a positive electrode plate. Furthermore, all the batteries were unified in weight and thickness in such a manner that they were subjected to the same test conditions.

對於相對電極，為了觀察正極的單獨行為，而將鋰金屬製成負極。使鋰金屬密接於鎳箔集電體。其中，鋰二次電池的容量是以成為充分正極控制的方式而製備。 For the opposite electrode, in order to observe the individual behavior of the positive electrode, lithium metal was made into a negative electrode. The lithium metal is adhered to the nickel foil current collector. Among them, the capacity of the lithium secondary battery is prepared in such a manner as to be sufficiently positively controlled.

電解液是利用使LiPF₆以濃度為1mol/l的方式溶解於EC/EMC/DMC為體積比6：7：7的混合溶劑中而成的溶液。隔離膜是使用經聚丙烯酸酯進行了表面改質以提高電解質的保持性的聚丙烯製微孔膜。另外，使用在鎳板上貼附有鋰金屬箔的物品作為參照電極。外裝體是使用由聚對苯二甲酸乙二酯(15μm)/鋁箔(50μm)/金屬黏接性聚丙烯薄膜(50μm)構成的金屬樹脂複合薄膜，以正極端子、負極端子及參照電極端子的開放端部露出在外部的方式收容電極，於上述金屬樹脂複合薄膜的內面彼此相向的 熔著部分將成為注液孔的部分除外而進行氣密密封。 The electrolytic solution was prepared by dissolving LiPF ₆ in a mixed solvent of EC/EMC/DMC in a volume ratio of 6:7:7 at a concentration of 1 mol/l. The separator is a polypropylene microporous membrane which is surface-modified with polyacrylate to improve the retention of the electrolyte. Further, an article in which a lithium metal foil was attached to a nickel plate was used as a reference electrode. The outer casing is a metal resin composite film composed of polyethylene terephthalate (15 μm)/aluminum foil (50 μm)/metal adhesive polypropylene film (50 μm), and a positive electrode terminal, a negative electrode terminal, and a reference electrode terminal. The open end portion is exposed to the outside so as to accommodate the electrode, and the portion where the inner surface of the metal-resin composite film facing each other is a portion to be the liquid-filled hole, and the hermetic sealing is performed.

將如上所述而製作的鋰二次電池於20℃下供於5循環的初期充放電步驟。電壓控制全部是對正極電位進行。充電是設定為電流0.1ItA、電壓4.5V的恆定電流恆定電壓充電，充電終止條件是設定為電流值衰減至1/6的時刻。放電是設定為電流0.1ItA、終止電壓2.0V的恆定電流放電。於所有循環中於充電後及放電後設定30分鐘的休止時間。對於實例1-1的鋰二次電池，於最初的充電時，自充電電量超過100mAh/g的附近起，於4.45V附近的電位處長期間觀察到電位變化相對較平坦的區域。 The lithium secondary battery fabricated as described above was supplied to an initial charge and discharge step of 5 cycles at 20 °C. The voltage control is all performed on the positive potential. The charging is a constant current constant voltage charging set to a current of 0.1 ItA and a voltage of 4.5 V, and the charging termination condition is set to a time at which the current value is attenuated to 1/6. The discharge was a constant current discharge set to a current of 0.1 ItA and a termination voltage of 2.0V. A rest period of 30 minutes was set after charging and after discharging in all cycles. In the lithium secondary battery of Example 1-1, at the time of the initial charging, a region where the potential change was relatively flat was observed during the period of the potential of 4.45 V from the vicinity of the self-charging amount exceeding 100 mAh/g.

繼而，進行充放電循環試驗。電壓控制全部是對正極電位進行。充放電循環試驗的條件除了將充電電壓設定為4.3V(vs.Li/Li+)以外，與上述初期充放電步驟的條件相同。於所有循環中於充電後及放電後設定30分鐘的休止時間。將該充放電循環試驗中第5循環的放電電量記錄為「放電電容(mAh/g)」。 Then, a charge and discharge cycle test was performed. The voltage control is all performed on the positive potential. The conditions of the charge and discharge cycle test were the same as those of the initial charge and discharge step except that the charge voltage was set to 4.3 V (vs. Li/Li+). A rest period of 30 minutes was set after charging and after discharging in all cycles. The discharge amount of the fifth cycle in the charge and discharge cycle test was recorded as "discharge capacity (mAh/g)".

然後，進行高率放電試驗。電壓控制全部是對正極電位進行。充放電循環試驗的條件除了將充電電壓設定為4.3V(vs.Li/Li+)以外，與上述初期充放電步驟的條件相同。其後的放電是設定為2ItA、終止電壓2.0V的恆定電流放電。於充電後及放電後設定30分鐘的休止時間。將上述2ItA時所得的放電電容相對於電流0.1ItA時所得的放電電容的比率記錄為「速率(rate)比率(%)」。 Then, a high rate discharge test was performed. The voltage control is all performed on the positive potential. The conditions of the charge and discharge cycle test were the same as those of the initial charge and discharge step except that the charge voltage was set to 4.3 V (vs. Li/Li+). The subsequent discharge was a constant current discharge set to 2 ItA and a termination voltage of 2.0V. The rest time of 30 minutes was set after charging and after discharging. The ratio of the discharge capacity obtained at the time of 2 ItA to the discharge capacity obtained at a current of 0.1 ItA was recorded as "rate ratio (%)".

將(003)面與(114)面的繞射波峰的強度比(面積 比)I₍₀₀₃₎/I₍₁₁₄₎的算出結果、充放電循環試驗結果(0.1C電容)、速率比率示於表1中。 The calculation results of the intensity ratio (area ratio) I ₍₀₀₃₎ / I ₍₁₁₄₎ of the diffraction peaks of the (003) plane and the (114) plane, the charge and discharge cycle test results (0.1 C capacitor), and the rate ratio are shown in the table. 1 in.

[表1] [Table 1]

於將鋰過渡金屬複合氧化物的固溶體所含有的金屬元素的組成比率(金屬元素比率)設定為Li_1+(x/3)Co_1-x-y-zNi_y/2Mg_z/2Mn_{(2x/3)+(y/2)+(z/2)}O₂時，實例1-1~實例1-5為x=0.6、y=0.278、z=0.022，實例1-6為x=0.51、y=0.36、z=0.04，實例1-7為x=0.63、y=0.12、z=0.04，實例1-8為x=0.54、y=0.30、z=0.06，實例1-9為x=0.60、y=0.30、z=0.02，均滿足上述金屬元素比率，具有可歸屬於空間群P3₁12的X射線繞射圖案，由X射線繞射測定所得的(003)面與(114)面的繞射波峰的強度比為I₍₀₀₃₎/I₍₁₁₄₎≧1.15，故實例1-1~實例1-9的活性物質可獲得超過200mAh/g的放電電容、65%以上的速率比率。因此確認到放電電容大，高率放電特性優異。 The composition ratio (metal element ratio) of the metal element contained in the solid solution of the lithium transition metal composite oxide is set to Li _1+(x/3) Co _1-xyz Ni _y/2 Mg _z/2 Mn _{(2x /3) +(y/2)+(z/2)} O ₂ , examples 1-1 to 1-5 are x=0.6, y=0.278, z=0.022, and examples 1-6 are x=0.51. y=0.36, z=0.04, examples 1-7 are x=0.63, y=0.12, z=0.04, examples 1-8 are x=0.54, y=0.30, z=0.06, and examples 1-9 are x=0.60. , y=0.30, z=0.02, both satisfying the above metal element ratio, having an X-ray diffraction pattern attributable to the space group P3 ₁ 12, and measuring (003) plane and (114) plane by X-ray diffraction measurement The intensity ratio of the diffraction peak is I ₍₀₀₃₎ / I ₍₁₁₄₎ ≧ 1.15, so the active materials of Examples 1-1 to 1-9 can obtain a discharge capacity of more than 200 mAh/g and a rate ratio of 65% or more. Therefore, it was confirmed that the discharge capacity was large and the high rate discharge characteristics were excellent.

比較例1-1~比較例1-4的活性物質的上述金屬元素比率與實例1-1~實例1-5相同，具有可歸屬於空間群P3₁12的X射線繞射圖案，但煅燒溫度分別為900℃、800℃、700℃、550℃，低於實例1-1~實例1-5的1000℃~920℃，故繞射波峰的強度比小至I₍₀₀₃₎/I₍₁₁₄₎<1.15，僅可獲得低於200mAh/g的放電電容，速率比率亦為50%以下。 The above-described metal element ratios of the active materials of Comparative Example 1-1 to Comparative Example 1-4 were the same as those of Examples 1-1 to 1-5, and had X-ray diffraction patterns attributable to the space group P3 ₁ 12, but the calcination temperature. 900 ° C, 800 ° C, 700 ° C, 550 ° C, respectively, lower than 1000 ° ~ 920 ° C of Example 1-1 ~ Example 1-5, so the intensity ratio of the diffraction peak is as small as I ₍₀₀₃₎ / I ₍₁₁₄₎ <1.15, only a discharge capacitance of less than 200 mAh/g can be obtained, and the rate ratio is also 50% or less.

另外，比較例1-5的活性物質的上述金屬元素比率與實例1-1~實例1-5相同，而煅燒溫度高至1100℃，故繞射波峰的強度比滿足I₍₀₀₃₎/I₍₁₁₄₎≧1.15，但不具有可歸屬於空間群P3₁12的射線繞射圖案，故放電電容及速率比率極低。 Further, the above-mentioned metal element ratios of the active materials of Comparative Examples 1 to 5 were the same as those of Examples 1-1 to 1-5, and the calcination temperature was as high as 1,100 ° C, so that the intensity ratio of the diffraction peaks satisfies I ₍₀₀₃₎ /I _{( 114)} ≧ 1.15, but does not have a ray diffraction pattern attributable to the space group P3 ₁ 12, so the discharge capacitance and rate ratio are extremely low.

比較例1-6~比較例1-9的活性物質的上述金屬元素比率分別與實例1-6~實例1-9相同，具有可歸屬於空間群P3₁12的X射線繞射圖案，但煅燒溫度為800℃，低於實例1-6~實例1-9的1000℃，故繞射波峰的強度比小至I₍₀₀₃₎/I₍₁₁₄₎<1.15，僅可獲得低於200mAh/g的放電電容，速率比率亦為56%以下。 The above-mentioned metal element ratios of the active materials of Comparative Example 1-6 to Comparative Example 1-9 were the same as those of Examples 1-6 to 1-9, respectively, and had an X-ray diffraction pattern attributable to the space group P3 ₁ 12, but calcined. The temperature is 800 ° C, which is lower than 1000 ° C of Examples 1-6 to 1-9, so the intensity ratio of the diffraction peak is as small as I ₍₀₀₃₎ /I ₍₁₁₄₎ <1.15, and only less than 200 mAh/g can be obtained. The discharge capacitor has a rate ratio of 56% or less.

比較例1-10~比較例1-15的活性物質不含Mg，但該活性物質亦如比較例1-10般，於煅燒溫度為1000℃時，鋰過渡金屬複合氧化物的固溶體具有可歸屬於空間群P3₁12的X射線繞射圖案，繞射波峰的強度比滿足I₍₀₀₃₎/I₍₁₁₄₎≧1.15，可獲得超過200mAh/g的放電電容。但是，速率比率為52%，與比較例1-11~比較例1-15的活性物質相同，高率放電特性差。因此，如實例1-1般，藉由使活性物質含有Mg，並於1000℃下進行煅燒，放電電容及高率放電特性一併提高，且如比較例1-10般，若活性物質不含Mg，則即便藉由在1000℃下煅燒而放電電容提高，高率放電特性亦不提高。 The active materials of Comparative Example 1-10 to Comparative Example 1-15 did not contain Mg, but the active material also had a solid solution of the lithium transition metal composite oxide at a calcination temperature of 1000 ° C as in Comparative Examples 1-10. The X-ray diffraction pattern attributable to the space group P3 ₁ 12, the intensity ratio of the diffraction peaks satisfies I ₍₀₀₃₎ /I ₍₁₁₄₎ ≧ 1.15, and a discharge capacitance exceeding 200 mAh/g can be obtained. However, the rate ratio was 52%, which was the same as that of the active materials of Comparative Example 1-11 to Comparative Example 1-15, and the high rate discharge characteristics were inferior. Therefore, as in the case of Example 1-1, by subjecting the active material to Mg and calcining at 1000 ° C, the discharge capacity and the high rate discharge characteristics were improved together, and as in Comparative Example 1-10, if the active material did not contain In Mg, even if the discharge capacity is increased by calcination at 1000 ° C, the high rate discharge characteristics are not improved.

進而，若將實例1-1與比較例1-10加以比較，則實例1-1的活性物質的放電電容為242mAh/g，相對於此，比較例1-10的活性物質的放電電容為223mAh/g，故可知，藉由以Mg替換一部分Ni，放電電容顯著提高。如此般藉由含有Mg而放電電容顯著提高的情況不可謂可預測。 Further, when Example 1-1 was compared with Comparative Example 1-10, the discharge capacity of the active material of Example 1-1 was 242 mAh/g, whereas the discharge capacity of the active material of Comparative Example 1-10 was 223 mAh. /g, it is understood that the discharge capacitance is remarkably improved by replacing a part of Ni with Mg. Such a situation in which the discharge capacitance is significantly increased by containing Mg is not predictable.

另外，實例1-3與比較例1-10為相同程度的放電電容，但比較例1-10的活性物質是於1000℃下經煅燒的物 質，相對於此，實例1-3的活性物質是於960℃下經煅燒的物質，因此可謂為了獲得相同程度的放電電容的活性物質，而藉由含有Mg來於低煅燒溫度下實現。因此，藉由採用本發明的活性物質，亦有可減少煅燒時供給於煅燒爐的能量的效果。 In addition, Examples 1-3 and Comparative Examples 1-10 have the same degree of discharge capacitance, but the active materials of Comparative Examples 1-10 are calcined at 1000 ° C. In contrast, the active material of Examples 1-3 is a material which is calcined at 960 ° C, and thus can be realized by obtaining Mg at a low calcination temperature in order to obtain an active material of the same degree of discharge capacity. Therefore, by using the active material of the present invention, the effect of energy supplied to the calciner at the time of calcination can be reduced.

另一方面，不含Mg的活性物質亦於煅燒溫度為900℃以下時，如比較例1-11~比較例1-14般，繞射波峰的強度比為I₍₀₀₃₎/I₍₁₁₄₎<1.15；但若將煅燒溫度為900℃的比較例1-1與比較例1-11加以比較，則含有Mg的比較例1-1的活性物質的放電電容為185mAh/g，相對於此，不含Mg的比較例1-11的活性物質的放電電容為186mAh/g；另外，若將煅燒溫度為800℃的比較例1-2與比較例1-12加以比較，則含有Mg的比較例1-2的活性物質的放電電容為165mAh/g，相對於此，不含Mg的比較例1-12的活性物質的放電電容為166mAh/g，故放電電容為相同程度(煅燒溫度為700℃、550℃時亦為相同程度)，即便以Mg替換一部分Ni，放電電容亦不提高。 On the other hand, when the active material containing no Mg is at a calcination temperature of 900 ° C or lower, as in Comparative Example 1-11 to Comparative Example 1-14, the intensity ratio of the diffraction peak is I ₍₀₀₃₎ /I _(114). <1.15; However, when Comparative Example 1-1 having a calcination temperature of 900 ° C was compared with Comparative Example 1-11, the discharge capacity of the active material of Comparative Example 1-1 containing Mg was 185 mAh/g, whereas The discharge capacity of the active material of Comparative Example 1-11 containing no Mg was 186 mAh/g, and Comparative Example 1-2 having a calcination temperature of 800 ° C was compared with Comparative Example 1-12 to obtain a comparative example containing Mg. The discharge capacity of the active material of 1-2 was 165 mAh/g. On the other hand, the discharge capacity of the active material of Comparative Example 1-12 containing no Mg was 166 mAh/g, so the discharge capacity was the same (calcination temperature was 700 ° C). At 550 ° C, the same level), even if a part of Ni is replaced by Mg, the discharge capacitance does not increase.

因此，為了使放電電容顯著提高，可謂不僅需要使鋰過渡金屬複合氧化物的固溶體所含有的金屬元素的組成比率為Li_1+(x/3)Co_1-x-y-zNi_y/2Mg_z/2Mn_{(2x/3)+(y/2)+(z/2)}(x>0、y>0、z>0、x+y+z<1)，而且需要使由X射線繞射測定所得的(003)面與(114)面的繞射波峰的強度比為I₍₀₀₃₎/I₍₁₁₄₎≧1.15。 Therefore, in order to remarkably increase the discharge capacity, it is necessary to make the composition ratio of the metal element contained in the solid solution of the lithium transition metal composite oxide Li _1+(x/3) Co _1-xyz Ni _y/2 Mg _{z /2} Mn _{(2x/3)+(y/2)+(z/2)} (x>0, y>0, z>0, x+y+z<1), and need to be diffracted by X-rays The intensity ratio of the diffraction peaks of the (003) plane and the (114) plane obtained was determined to be I ₍₀₀₃₎ / I ₍₁₁₄₎ ≧ 1.15.

對於如比較例1-16~比較例1-19般含有Al或Ti代替 Mg的經1000℃下煅燒的活性物質，鋰過渡金屬複合氧化物的固溶體具有可歸屬於空間群P3₁12的X射線繞射圖案，繞射波峰的強度比滿足I₍₀₀₃₎/I₍₁₁₄₎≧1.15，但無法獲得超過200mAh/g的放電電容，高率放電特性亦差。 The solid solution of the lithium transition metal composite oxide having an active material calcined at 1000 ° C containing Al or Ti instead of Mg as in Comparative Example 1-16 to Comparative Example 1-19 has a solid solution which can be attributed to the space group P3 ₁ 12 In the X-ray diffraction pattern, the intensity ratio of the diffraction peak satisfies I ₍₀₀₃₎ / I ₍₁₁₄₎ ≧ 1.15, but a discharge capacitance exceeding 200 mAh/g cannot be obtained, and the high-rate discharge characteristics are also poor.

如上所述，本發明的活性物質藉由滿足「鋰過渡金屬複合氧化物的固溶體所含有的金屬元素的組成比率滿足Li_1+(x/3)Co_1-x-y-zNi_y/2Mg_z/2Mn_{(2x/3)+(y/2)+(z/2)}(x>0、y>0、z>0、x+y+z<1)」、「具有可歸屬於空間群P3₁12的X射線繞射圖案」、「由X射線繞射測定所得的(003)面與(114)面的繞射波峰的強度比為I₍₀₀₃₎/I₍₁₁₄₎≧1.15」三個要件，可獲得超過200mAh/g的大的放電電容，且可謂高率放電特性優異。 As described above, the active material of the present invention satisfies the composition ratio of the metal element contained in the solid solution of the lithium transition metal composite oxide to satisfy Li _1+(x/3) Co _1-xyz Ni _y/2 Mg _{z /2} Mn _{(2x/3)+(y/2)+(z/2)} (x>0, y>0, z>0, x+y+z<1)”, “has a space group attributable to "X-ray diffraction pattern of P3 ₁ 12", "The intensity ratio of the diffraction peaks of the (003) plane and the (114) plane obtained by X-ray diffraction measurement is I ₍₀₀₃₎ / I ₍₁₁₄₎ ≧ 1.15" According to the requirements, a large discharge capacity of more than 200 mAh/g can be obtained, and it is excellent in high rate discharge characteristics.

[實例2] [Example 2]

(實例2-1) (Example 2-1)

與實例1-1同樣地於煅燒溫度1000℃下合成組成為Li_1.2Co_0.1Ni_0.139Mg_0.011Mn_0.55O₂的活性物質。 The active material having a composition of Li _1.2 Co _0.1 Ni _0.139 Mg _0.011 Mn _0.55 O ₂ was synthesized at a calcination temperature of 1000 ° C in the same manner as in Example 1-1.

關於所得的活性物質的結晶構造，與實例1-1同樣地進行使用Cu(Kα)管球的粉末X射線繞射測定，結果確認到α-NaFeO₂型的六方晶構造為主相，並且部分觀察到Li[Li_1/3Mn_2/3]O₂型的單斜晶中可見的20°~30°附近的繞射波峰。對這些所有的繞射線藉由Rietveld法進行結晶構造分析，結果與歸屬於空間群P3₁12的結晶構造模型非常一致。 The crystal structure of the obtained active material was measured by powder X-ray diffraction using a Cu(Kα) tube ball in the same manner as in Example 1-1, and it was confirmed that the α-NaFeO ₂ type hexagonal crystal structure was the main phase, and the part was confirmed. A diffraction peak near 20° to 30° visible in a monoclinic crystal of the Li[Li _1/3 Mn _2/3 ]O ₂ type was observed. The crystal structure analysis of all these ray rays by the Rietveld method is very consistent with the crystal structure model attributed to the space group P3 ₁ 12 .

另外，由2θ：18.6±1°時的繞射波峰求出(003)面的 繞射波峰的半高寬，結果為0.14°，由2θ：44.1±1°時的繞射波峰求出(114)面的繞射波峰的半高寬，結果為0.23°。 In addition, the (003) plane is obtained from the diffraction peak at 2θ: 18.6±1°. The full width at half maximum of the diffraction peak was 0.14°, and the full width at half maximum of the diffraction peak of the (114) plane was obtained from the diffraction peak at 2θ: 44.1 ± 1°, and as a result, it was 0.23°.

進而，對X射線繞射圖形的資料於電腦上進行Rietveld分析，於該分析過程中，使高斯函數及勞倫茲函數所含的結晶參數精密化，根據如此而求出的結晶參數分別算出晶格變形及微晶尺寸，結果微晶尺寸為180nm。 Further, the data of the X-ray diffraction pattern is subjected to Rietveld analysis on a computer, and in the analysis process, the crystallization parameters contained in the Gaussian function and the Lorentz function are refined, and the crystal parameters obtained from the crystal parameters are respectively calculated. The lattice deformation and crystallite size, the result crystallite size is 180 nm.

(實例2-2~實例2-10) (Example 2-2~Example 2-10)

對於共沈澱氫氧化物前驅物所含有的金屬元素的組成及氫氧化鋰一水合物的混合量，按表2的實例2-2~實例2-10所示的組成式進行變更，除此以外，與實例2-1同樣地合成本發明的活性物質。 The composition of the metal element contained in the coprecipitated hydroxide precursor and the amount of lithium hydroxide monohydrate mixed are changed according to the composition formulas shown in Examples 2-2 to 2-10 of Table 2, and The active material of the present invention was synthesized in the same manner as in Example 2-1.

X射線繞射測定的結果與實例2-1相同，確認到α-NaFeO₂型的六方晶構造為主相，並且部分觀察到Li[Li_1/3Mn_2/3]O₂型的單斜晶中可見的20°~30°附近的繞射波峰。對該些所有的繞射線藉由Rietveld法進行結晶構造分析，結果與歸屬於空間群P3₁12的結晶構造模型非常一致。 The results of the X-ray diffraction measurement were the same as those in Example 2-1, and it was confirmed that the hexagonal crystal structure of the α-NaFeO ₂ type was the main phase, and the monoclinic form of the Li[Li _1/3 Mn _2/3 ]O ₂ type was partially observed. Diffraction peaks around 20°~30° visible in the crystal. The crystal structure analysis of all the diffraction rays by the Rietveld method is very consistent with the crystal structure model attributed to the space group P3 ₁ 12 .

另外，由2θ：18.6±1°時的繞射波峰求出(003)面的繞射波峰的半高寬，結果為0.14°~0.15°，由2θ：44.1±1°時的繞射波峰求出(114)面的繞射波峰的半高寬，結果為0.23°~0.25°。 Further, the full width at half maximum of the diffraction peak of the (003) plane is obtained from the diffraction peak at 2θ: 18.6±1°, and as a result, it is 0.14° to 0.15°, and the diffraction peak at 2θ: 44.1±1° is obtained. The full width at half maximum of the diffraction peak of the (114) plane is 0.23° to 0.25°.

進而，與實例2-1同樣地算出微晶尺寸，結果微晶尺寸為180nm~200nm。 Further, the crystallite size was calculated in the same manner as in Example 2-1, and as a result, the crystallite size was 180 nm to 200 nm.

(比較例2-1~比較例2-4) (Comparative Example 2-1 to Comparative Example 2-4)

自共沈澱氫氧化物前驅物所含有的金屬元素中去掉Mg，按表2的比較例2-1~比較例2-4所示的組成式進行變更，對於比較例2-1~比較例2-4，將煅燒溫度分別變更為1000℃、900℃、800℃、700℃，除此以外，與實例2-1同樣地合成比較例的活性物質。 The Mg was removed from the metal element contained in the coprecipitated hydroxide precursor, and was changed according to the composition formulas shown in Comparative Example 2-1 to Comparative Example 2-4 of Table 2, and Comparative Example 2-1 to Comparative Example 2 were changed. -4, the active material of the comparative example was synthesized in the same manner as in Example 2-1 except that the calcination temperature was changed to 1000 ° C, 900 ° C, 800 ° C, and 700 ° C, respectively.

與實例2-1同樣地求出(003)面、(114)面的繞射波峰的半高寬，算出微晶尺寸。 The full width at half maximum of the diffraction peaks of the (003) plane and the (114) plane were obtained in the same manner as in Example 2-1, and the crystallite size was calculated.

(比較例2-5~比較例2-7) (Comparative Example 2-5 to Comparative Example 2-7)

對於比較例2-5~比較例2-7，將與實例2-2(煅燒溫度1000℃)相同組成的固溶體的煅燒溫度分別變更為700℃、800℃、900℃，除此以外，與實例2-1同樣地合成比較例的活性物質。 In Comparative Example 2-5 to Comparative Example 2-7, the calcination temperature of the solid solution having the same composition as that of Example 2-2 (calcination temperature: 1000 ° C) was changed to 700 ° C, 800 ° C, and 900 ° C, respectively. The active material of the comparative example was synthesized in the same manner as in Example 2-1.

與實例2-1同樣地求出(003)面、(114)面的繞射波峰的半高寬，算出微晶尺寸。 The full width at half maximum of the diffraction peaks of the (003) plane and the (114) plane were obtained in the same manner as in Example 2-1, and the crystallite size was calculated.

(比較例2-8~比較例2-14) (Comparative Example 2-8 to Comparative Example 2-14)

比較例2-8~比較例2-10是設定為與實例2-3、實例2-1、實例2-4相同的固溶體組成，比較例2-11~比較例2-14是設定為與實例2-7~實例2-10相同的固溶體組成，並將煅燒溫度從1000℃變更為900℃，除此以外，與實例2-1同樣地合成比較例的活性物質。 Comparative Example 2-8 to Comparative Example 2-10 were set to have the same solid solution composition as in Example 2-3, Example 2-1, and Example 2-4, and Comparative Example 2-11 to Comparative Example 2-14 were set to The active material of the comparative example was synthesized in the same manner as in Example 2-1 except that the composition of the solid solution was the same as that of the example 2-7 to the example 2-10, and the calcination temperature was changed from 1000 ° C to 900 ° C.

與實例2-1同樣地求出(003)面、(114)面的繞射波峰的半高寬，算出微晶尺寸。 The full width at half maximum of the diffraction peaks of the (003) plane and the (114) plane were obtained in the same manner as in Example 2-1, and the crystallite size was calculated.

(比較例2-15、比較例2-16) (Comparative Example 2-15, Comparative Example 2-16)

對於共沈澱氫氧化物前驅物所含有的過渡金屬元素的 組成及氫氧化鋰一水合物的混合量，按表2的比較例2-15、比較例2-16所示的組成式進行變更，除此以外，與實例2-1同樣地合成比較例的活性物質。 For the transition metal elements contained in the coprecipitated hydroxide precursor The composition of the comparative example was synthesized in the same manner as in Example 2-1 except that the composition and the amount of the lithium hydroxide monohydrate were changed according to the composition formulas shown in Comparative Example 2-15 and Comparative Example 2-16 of Table 2. Active substance.

與實例2-1同樣地求出(003)面、(114)面的繞射波峰的半高寬，算出微晶尺寸。 The full width at half maximum of the diffraction peaks of the (003) plane and the (114) plane were obtained in the same manner as in Example 2-1, and the crystallite size was calculated.

(比較例2-17) (Comparative Example 2-17)

與比較例1-16同樣地合成含有Al代替Mg的活性物質Li_1.2Co_0.1Ni_0.144Al_0.012Mn_0.544O₂。 The active material Li _1.2 Co _0.1 Ni _0.144 Al _0.012 Mn _0.544 O ₂ containing Al instead of Mg was synthesized in the same manner as in Comparative Example 1-16.

(比較例2-18) (Comparative Example 2-18)

與比較例1-17同樣地合成含有Al代替Mg的活性物質Li_1.2Co_0.1Ni_0.1395Al_0.021Mn_0.5395O₂。 The active material Li _1.2 Co _0.1 Ni _0.1395 Al _0.021 Mn _0.5395 O ₂ containing Al instead of Mg was synthesized in the same manner as in Comparative Example 1-17.

(比較例2-19) (Comparative Example 2-19)

與比較例1-18同樣地合成含有Ti代替Mg的活性物質Li_1.2Co_0.1Ni_0.15Ti_0.03Mn_0.52O₂。 The active material Li _1.2 Co _0.1 Ni _0.15 Ti _0.03 Mn _0.52 O ₂ containing Ti instead of Mg was synthesized in the same manner as in Comparative Example 1-18.

(比較例2-20) (Comparative Example 2-20)

與比較例1-19同樣地合成含有Ti代替Mg的活性物質Li_1.2Co_0.1Ni_0.15Ti_0.05Mn_0.5O₂。 In the same manner as in Comparative Example 1-19, Li _1.2 Co _0.1 Ni _0.15 Ti _0.05 Mn _0.5 O ₂ containing Ti instead of Mg was synthesized.

(鋰二次電池的製作及評價) (Production and evaluation of lithium secondary battery)

使用實例2-1~實例2-10及比較例2-1~比較例2-20的各活性物質作為鋰二次電池用正極活性物質，按與實例1相同的順序製作鋰二次電池，評價電池特性。 Using each of the active materials of Examples 2-1 to 2-10 and Comparative Example 2-1 to Comparative Example 2-20 as a positive electrode active material for a lithium secondary battery, a lithium secondary battery was produced in the same manner as in Example 1 and evaluated. Battery characteristics.

將半高寬的測定結果、結晶尺寸的算出結果、充放電循環試驗結果(0.1C電容)、速率比率示於表2中。 The measurement results of the full width at half maximum, the calculation results of the crystal size, the charge and discharge cycle test results (0.1 C capacitance), and the rate ratio are shown in Table 2.

[表2] [Table 2]

實例2-1~實例2-6、比較例2-5~比較例2-10是於設想固溶體xLi[Li_1/3Mn_2/3]O₂-yLiNi_1/2Mn_1/2O₂-zLiMg_1/2Mn_1/2O₂-(1-x-y-z)LiCoO₂(x>0、y>0、z>0、x+y+z<1)的基礎上，按照藉由Mg²⁺ _1/2Mn⁴⁺ _1/2來替換構成LiNi_1/2Mn_1/2O₂的Ni²⁺ _1/2Mn⁴⁺ _1/2部分的思想，以滿足式Li_1+(x/3)Co_1-x-y-zNi_y/2Mg_z/2Mn_{(2x/3)+(y/2)+(z/2)}(x>0、y>0、z>0、x+y+z<1)的方式設定各金屬元素的組成比率(金屬元素比率)。 Examples 2-1 to 2-6, and Comparative Examples 2-5 to 2-10 are for the solid solution xLi[Li _1/3 Mn _2/3 ]O ₂ -yLiNi _1/2 Mn _1/2 O ₂ -zLiMg _1/2 Mn _1/2 O ₂ -(1-xyz)LiCoO ₂ (x>0, y>0, z>0, x+y+z<1), based on Mg ^{2 +} _1/2 Mn ⁴⁺ _1/2 to replace the Ni ²⁺ _1/2 Mn ⁴⁺ _1/2 moiety constituting LiNi _1/2 Mn _1/2 O ₂ to satisfy the formula Li _{1+(x/3 )} Co _1-xyz Ni _y/2 Mg _z/2 Mn _{(2x/3)+(y/2)+(z/2)} (x>0, y>0, z>0, x+y+z< The method of 1) sets the composition ratio (metal element ratio) of each metal element.

關於實例2-1~實例2-6，上述金屬比率在本發明的規定範圍內，(003)面的繞射波峰的半高寬為0.14°~0.15°，且(114)面的繞射波峰的半高寬為0.23°~0.25°。 With respect to Examples 2-1 to 2-6, the above metal ratio is within the range of the present invention, and the half-height of the diffraction peak of the (003) plane is 0.14° to 0.15°, and the diffraction peak of the (114) plane The full width at half maximum is 0.23°~0.25°.

比較例2-5~比較例2-7的上述金屬元素比率與實例2-2相同，但煅燒溫度分別為700℃、800℃、900℃，低於實例2-2的1000℃，故(003)面的繞射波峰的半高寬分別為0.31°、0.21°、0.17°，大於實例2-2的0.14°，(114)面的繞射波峰的半高寬亦分別為0.45°、0.31°、0.28°，大於實例2-2的0.24°。 The above metal element ratios of Comparative Example 2-5 to Comparative Example 2-7 were the same as those of Example 2-2, but the calcination temperatures were 700 ° C, 800 ° C, and 900 ° C, respectively, which was lower than 1000 ° C of Example 2-2, so (003 The half-height widths of the diffraction peaks of the plane are 0.31°, 0.21°, and 0.17°, respectively, which is greater than 0.14° of Example 2-2. The half-height widths of the diffraction peaks of the (114) plane are also 0.45° and 0.31°, respectively. 0.28°, which is greater than 0.24° of Example 2-2.

另外，關於微晶尺寸，實例2-2為180nm，相對於此，比較例2-5~比較例2-7分別為80nm、110nm、140nm，可知煅燒溫度越低則微晶尺寸越小。 Further, regarding the crystallite size, Example 2-2 was 180 nm, whereas Comparative Example 2-5 to Comparative Example 2-7 were 80 nm, 110 nm, and 140 nm, respectively, and it was found that the lower the calcination temperature, the smaller the crystallite size.

比較例2-8~比較例2-10的上述金屬元素比率與實例2-3、實例2-1、實例2-4相同，但煅燒溫度為900℃，低於實例2-3、實例2-1、實例2-4的1000℃，故(003)面的 繞射波峰的半高寬為0.16°~0.17°，大於實例2-3、實例2-1、實例2-4的0.14°，(114)面的繞射波峰的半高寬亦為0.28°~0.29°，大於實例2-3、實例2-1、實例2-4的0.23°~0.24°。 The above metal element ratios of Comparative Example 2-8 to Comparative Example 2-10 were the same as those of Example 2-3, Example 2-1, and Example 2-4, but the calcination temperature was 900 ° C, which was lower than Examples 2-3 and Example 2 1. Example 2-4 at 1000 °C, so (003) The full width at half maximum of the diffraction peak is 0.16°~0.17°, which is greater than 0.14° in Example 2-3, Example 2-1 and Example 2-4. The half-height of the diffraction peak of the (114) plane is also 0.28°~ 0.29°, which is greater than 0.23°~0.24° of Example 2-3, Example 2-1, and Example 2-4.

另外，關於微晶尺寸，實例2-3、實例2-1、實例2-4為180nm~200nm，相對於此，比較例2-8~比較例2-10為130nm~140nm，微晶尺寸小。 In addition, regarding the crystallite size, Example 2-3, Example 2-1, and Example 2-4 are 180 nm to 200 nm, whereas Comparative Example 2-8 to Comparative Example 2-10 are 130 nm to 140 nm, and the crystallite size is small. .

實例2-7~實例2-10、比較例2-11~比較例2-14是於同樣設想固溶體xLi[Li_1/3Mn_2/3]O₂-yLiNi_1/2Mn_1/2O₂-zLiMg_1/2Mn_1/2O₂-(1-x-y-z)LiCoO₂(x>0、y>0、z>0、x+y+z<1)的基礎上，按照藉由[Mg_1/2Mn_1/2]³⁺來替換構成Li[Li_1/3Mn_2/3]O₂的[Li_1/3Mn_2/3]³⁺部分的思想，以滿足式Li_1+(x/3)Co_1-x-y-zNi_y/2Mg_z/2Mn_{(2x/3)+(y/2)+(z/2)}(x>0、y>0、z>0、x+y+z<1)的方式設定各金屬元素比率。 Examples 2-7 to 2-10, and Comparative Examples 2-11 to 2-14 are similarly contemplated as solid solution xLi[Li _1/3 Mn _2/3 ]O ₂ -yLiNi _1/2 Mn _1/2 O ₂ -zLiMg _1/2 Mn _1/2 O ₂ -(1-xyz)LiCoO ₂ (x>0, y>0, z>0, x+y+z<1), based on Mg _1/2 Mn _1/2 ] ³⁺ replaces the idea of [Li _1/3 Mn _2/3 ] ³⁺ portion of Li[Li _1/3 Mn _2/3 ]O ₂ to satisfy the formula Li _{1+ (x/3)} Co _1-xyz Ni _y/2 Mg _z/2 Mn _{(2x/3)+(y/2)+(z/2)} (x>0, y>0, z>0, x+ The ratio of each metal element is set in the manner of y+z<1).

關於實例2-7~實例2-10，上述金屬比率在本發明的規定範圍內，(003)面的繞射波峰的半高寬為0.14°~0.15°，且(114)面的繞射波峰的半高寬為0.23°~0.25°。 With respect to Examples 2-7 to 2-10, the above metal ratio is within the range specified by the present invention, and the half-height width of the diffraction peak of the (003) plane is 0.14° to 0.15°, and the diffraction peak of the (114) plane The full width at half maximum is 0.23°~0.25°.

比較例2-11~比較例2-14的上述金屬元素比率與實例2-7~實例2-10相同，但煅燒溫度為900℃，低於實例2-7~實例2-10的1000℃，故(003)面的繞射波峰的半高寬大至0.16°~0.17°，(114)面的繞射波峰的半高寬亦大至0.28°~0.29°。 The above metal element ratios of Comparative Examples 2-11 to Comparative Examples 2-14 were the same as those of Examples 2-7 to 2-10, but the calcination temperature was 900 ° C, which was lower than 1000 ° C of Examples 2-7 to 2-10. Therefore, the half-height of the diffraction peak of the (003) plane is as large as 0.16°~0.17°, and the half-height width of the diffraction peak of the (114) plane is also as large as 0.28°~0.29°.

另外，關於微晶尺寸，實例2-7~實例2-10為180nm ~200nm，相對於此，比較例2-11~比較例2-14為130nm~140nm，微晶尺寸小。 In addition, regarding the crystallite size, examples 2-7 to 2-10 are 180 nm. ~200 nm, in contrast, Comparative Example 2-11 to Comparative Example 2-14 were 130 nm to 140 nm, and the crystallite size was small.

固溶體滿足上述金屬元素比率、(003)面的繞射波峰的半高寬為0.15°以下、且(114)面的繞射波峰的半高寬為0.25°以下的實例2-1~實例2-10的活性物質可獲得超過200mAh/g的放電電容，與除了固溶體不含Mg以外和實例2-2為相同組成的比較例2-1~比較例2-4的活性物質相比較，0.1C的放電電容提高。另外，實例2-1~實例2-10的活性物質的速率比率為58%以上，與比較例2-1~比較例2-4的活性物質相比較，確認到速率比率顯著提高，高率放電特性優異。 The solid solution satisfies the above-described ratio of the metal element, the half-height width of the diffraction peak of the (003) plane is 0.15° or less, and the half-height width of the diffraction peak of the (114) plane is 0.25° or less. The active material of 2-10 can obtain a discharge capacity of more than 200 mAh/g, compared with the active materials of Comparative Example 2-1 to Comparative Example 2-4 having the same composition as Example 2-2 except that the solid solution does not contain Mg. The discharge capacitance of 0.1C is increased. Further, the rate ratio of the active materials of Examples 2-1 to 2-10 was 58% or more, and it was confirmed that the rate ratio was remarkably improved as compared with the active materials of Comparative Examples 2-1 to 2-4, and the high rate discharge was observed. Excellent characteristics.

相對於此，如比較例2-5~比較例2-14的活性物質般，即便固溶體滿足上述金屬元素比率，於(003)面的繞射波峰的半高寬超過0.15°、(114)面的繞射波峰的半高寬超過0.25°時，僅可獲得低於200mAh/g的放電電容，速率比率亦為54%以下，與除了固溶體不含Mg以外和實例2-2相同的比較例2-1~比較例2-4的活性物質相比較，0.1C的放電電容、速率比率(高率放電特性)均未提高。 On the other hand, as in the case of the active materials of Comparative Example 2-5 to Comparative Example 2-14, even if the solid solution satisfies the above-described ratio of the metal element, the full width at half maximum of the diffraction peak on the (003) plane exceeds 0.15° (114). When the full width at half maximum of the diffraction peak of the surface exceeds 0.25°, only a discharge capacitance of less than 200 mAh/g can be obtained, and the rate ratio is also 54% or less, which is the same as Example 2-2 except that the solid solution does not contain Mg. In the comparative examples 2-1 to 2-4, the discharge capacity and the rate ratio (high rate discharge characteristics) of 0.1 C were not improved as compared with the active materials of Comparative Example 2-4.

另外，比較例2-1的活性物質的(003)面的繞射波峰的半高寬為0.15°以下，且(114)面的繞射波峰的半高寬為0.25°以下，即，在本發明的範圍內，與上述半高寬在本發明的範圍外的比較例2-2~比較例2-4的活性物質相比較，0.1C的放電電容提高，但看不到速率比率的提高，於固溶體不含Mg時，不僅減小(003)面及(114)面的繞 射波峰的半高寬，而且高率放電特性不可謂提高。 Further, the full width at half maximum of the diffraction peak of the (003) plane of the active material of Comparative Example 2-1 was 0.15° or less, and the full width at half maximum of the diffraction peak of the (114) plane was 0.25° or less, that is, In the range of the invention, the discharge capacity of 0.1 C is improved as compared with the active materials of Comparative Example 2-2 to Comparative Example 2-4 in which the full width at half maximum is outside the range of the present invention, but the rate ratio is not improved. When the solid solution does not contain Mg, not only the (003) plane but also the (114) plane is reduced. The full width at half maximum of the wave peak and the high rate discharge characteristics are not improved.

比較例2-15是於成為Li¹⁺、Mn⁴⁺、Ni²⁺、Co³⁺、Mg²⁺的條件下以Mg來替換相當於x=0、y=2/3、z=0的活性物質LiCo_1/3Ni_1/3Mn_1/3O₂的一部分過渡金屬位點，具體而言，示出相當於x=0、y=0.56、z=0.10時的結果。煅燒溫度與實例相同而為1000℃，(003)及(114)繞射波峰的半高寬亦相同。此時，雖然可保持價數條件，但如非專利文獻6所記載，與作為不含Mg的上述活性物質的比較例2-16相比，儘管為相同的煅燒溫度、(003)及(114)繞射波峰的半高寬，亦可見放電電容的降低。 Comparative Example 2-15 replaces x=0, y=2/3, and z=0 with Mg under the conditions of Li ¹⁺ , Mn ⁴⁺ , Ni ²⁺ , Co ³⁺ , and Mg ²⁺ . A part of the transition metal sites of the active material LiCo _1/3 Ni _1/3 Mn _1/3 O ₂ , specifically, results corresponding to x=0, y=0.56, and z=0.10. The calcination temperature was 1000 ° C as in the example, and the half widths of the diffraction peaks of (003) and (114) were also the same. In this case, although the valence condition can be maintained, as described in Non-Patent Document 6, the same calcination temperature, (003), and (114) are obtained as compared with Comparative Example 2-16 which is the above-mentioned active material containing no Mg. The half-height width of the diffraction peak can also be seen as a decrease in the discharge capacitance.

實例2-1~實例2-10的活性物質的(003)面的繞射波峰的半高寬為0.15°以下，且(114)面的繞射波峰的半高寬為0.25°以下，隨之微晶尺寸亦大至180nm以上，高率放電特性提高。 The half-height width of the diffraction peak of the (003) plane of the active material of Example 2-1 to Example 2-10 was 0.15° or less, and the full width at half maximum of the diffraction peak of the (114) plane was 0.25° or less. The crystallite size is also as large as 180 nm or more, and the high rate discharge characteristics are improved.

相對於此，比較例2-2~比較例2-14的活性物質的半高寬大，隨之微晶尺寸小至140nm以下，高率放電特性不提高。 On the other hand, the active material of Comparative Example 2-2 to Comparative Example 2-14 had a large full width at half maximum, and the crystallite size was as small as 140 nm or less, and the high rate discharge characteristics were not improved.

另外，比較例2-1的活性物質的半高寬小至與實例2-1~實例2-10相同程度，故微晶尺寸為180nm以上，但由於固溶體不含Mg，故高率放電特性不提高。 Further, the full width at half maximum of the active material of Comparative Example 2-1 was as small as that of Examples 2-1 to 2-10, so the crystallite size was 180 nm or more, but since the solid solution contained no Mg, the high rate discharge was performed. Features are not improved.

比較例2-15的活性物質含有Mg，微晶尺寸為180nm以上，但於過渡金屬位點含有Li⁺，0.1C的放電電容、速率比率(高率放電特性)均未提高。 The active material of Comparative Example 2-15 contained Mg, and the crystallite size was 180 nm or more. However, Li ^{+ was} contained in the transition metal site, and the discharge capacity and rate ratio (high rate discharge characteristics) of 0.1 C were not improved.

比較例2-16的活性物質的微晶尺寸為180nm以上， 高率放電特性優異，但過渡金屬位點含有Li⁺，0.1C的放電電容未提高。 The active material of Comparative Example 2-16 had a crystallite size of 180 nm or more and was excellent in high rate discharge characteristics, but the transition metal site contained Li ⁺ and the discharge capacity of 0.1 C was not improved.

因此，為了維持高的放電電容並且使高率放電特性提昇，較佳為使固溶體滿足上述金屬元素比率，並且使微晶尺寸為180nm以上。 Therefore, in order to maintain a high discharge capacity and to improve the high rate discharge characteristics, it is preferred that the solid solution satisfies the above metal element ratio and the crystallite size is 180 nm or more.

關於如比較例2-17~比較例2-20般含有Al或Ti代替Mg的經1000℃下煅燒的活性物質，鋰過渡金屬複合氧化物的固溶體具有可歸屬於空間群P3₁12的X射線繞射圖案，X射線繞射圖中(003)面的繞射波峰的半高寬為0.15°以下，且(114)面的繞射波峰的半高寬為0.25°以下，但無法獲得超過200mAh/g的放電電容，高率放電特性亦差。 With respect to the active material calcined at 1000 ° C containing Al or Ti instead of Mg as in Comparative Example 2-17 to Comparative Example 2-20, the solid solution of the lithium transition metal composite oxide has a group which can be attributed to the space group P3 ₁ 12 X-ray diffraction pattern, the half-height width of the diffraction peak of the (003) plane in the X-ray diffraction pattern is 0.15° or less, and the half-height width of the diffraction peak of the (114) plane is 0.25° or less, but cannot be obtained. With a discharge capacitance exceeding 200 mAh/g, the high rate discharge characteristics are also poor.

如以上所述，本發明的活性物質藉由滿足「鋰過渡金屬複合氧化物的固溶體所含有的金屬元素的組成比率滿足Li_1+(x/3)Co_1-x-y-zNi_y/2Mg_z/2Mn_{(2x/3)+(y/2)+(z/2)}(x>0、y>0、z>0、x+y+z<1)」、「具有可歸屬於空間群P3₁12的X射線繞射圖案」、「X射線繞射圖中(003)面的繞射波峰的半高寬為0.15°以下，且(114)面的繞射波峰的半高寬為0.25°以下」三個要件，可獲得超過200mAh/g的大的放電電容，且可謂高率放電特性顯著提高。 As described above, the active material of the present invention satisfies the composition ratio of the metal element contained in the solid solution of the lithium transition metal composite oxide to satisfy Li _1+(x/3) Co _1-xyz Ni _y/2 Mg _z/2 Mn _{(2x/3)+(y/2)+(z/2)} (x>0, y>0, z>0, x+y+z<1)”, “has a space attributable to The X-ray diffraction pattern of the group P3 ₁ 12 and the half-height width of the diffraction peak of the (003) plane in the X-ray diffraction pattern are 0.15° or less, and the full width at half maximum of the diffraction peak of the (114) plane is With a requirement of three elements of 0.25° or less, a large discharge capacity of more than 200 mAh/g can be obtained, and high rate discharge characteristics are remarkably improved.

[實例3] [Example 3]

(實例3-1) (Example 3-1)

與實例1-1同樣地合成組成為Li_1.2Co_0.1Ni_0.139Mg_0.011Mn_0.55O₂的活性物質(與實例2中的實例2-1相同的活性物質)。 The active material having the composition of Li _1.2 Co _0.1 Ni _0.139 Mg _0.011 Mn _0.55 O ₂ (the same active material as Example 2-1 in Example 2) was synthesized in the same manner as in Example 1-1.

(比較例3-1) (Comparative Example 3-1)

自共沈澱氫氧化物前驅物所含有的金屬元素中去掉Mg，除此以外，與實例3-1同樣地合成比較例3-1的活性物質(與實例2中的比較例2-1相同的活性物質)。 The active material of Comparative Example 3-1 was synthesized in the same manner as in Example 3-1 except that Mg was removed from the metal element contained in the coprecipitated hydroxide precursor (the same as Comparative Example 2-1 in Example 2). Active substance).

(比較例3-2) (Comparative Example 3-2)

對於共沈澱氫氧化物前驅物所含有的過渡金屬元素的組成及氫氧化鋰一水合物的混合量，按表3的比較例3-2所示的組成式進行變更，除此以外，與實例3-1同樣地合成LiCo_0.33Ni_0.32Mg_0.013Mn_0.33O₂的活性物質。 The composition of the transition metal element contained in the coprecipitated hydroxide precursor and the mixing amount of the lithium hydroxide monohydrate were changed according to the composition formula shown in Comparative Example 3-2 of Table 3, and other examples were given. The active material of LiCo _0.33 Ni _0.32 Mg _0.013 Mn _0.33 O ₂ was synthesized in the same manner.

(比較例3-3) (Comparative Example 3-3)

自共沈澱氫氧化物前驅物所含有的金屬元素中去掉Mg，除此以外，與比較例3-2同樣地合成比較例3-3的活性物質(與實例2中的比較例2-16相同的活性物質)。 The active material of Comparative Example 3-3 was synthesized in the same manner as in Comparative Example 3-2 except that Mg was removed from the metal element contained in the coprecipitated hydroxide precursor (the same as Comparative Example 2-16 in Example 2). Active substance).

與實例2同樣地求出(003)面的繞射波峰的半高寬、(114)面的繞射波峰的半高寬，算出微晶尺寸。 In the same manner as in Example 2, the full width at half maximum of the diffraction peak of the (003) plane and the full width at half maximum of the diffraction peak of the (114) plane were obtained, and the crystallite size was calculated.

比較例3-2的活性物質為Li[Li_1/3Mn_2/3]O₂(x)：0.000，LiNi_1/2Mn_1/2O₂(y)：0.641、LiMg_1/2Mn_1/2O₂(z)：0.026、LiCoO₂(1-x-y-z)：0.333、(003)面的繞射波峰的半高寬為0.14°，(114)面的繞射波峰的半高寬為0.23°，微晶尺寸為190nm。 The active material of Comparative Example 3-2 was Li[Li _1/3 Mn _2/3 ]O ₂ (x): 0.000, LiNi _1/2 Mn _1/2 O ₂ (y): 0.641, LiMg _1/2 Mn _{1 /2} O ₂ (z): 0.026, LiCoO ₂ (1-xyz): 0.333, the half-height of the diffraction peak of the (003) plane is 0.14°, and the full width at half maximum of the diffraction peak of the (114) plane is 0.23. °, the crystallite size is 190 nm.

(鋰二次電池的製作及評價) (Production and evaluation of lithium secondary battery)

使用實例3-1及比較例3-1~比較例3-3的各活性物質作為鋰二次電池用正極活性物質，按與實例1相同的順序製作鋰二次電池，評價電池特性。 Using each active material of Example 3-1 and Comparative Example 3-1 to Comparative Example 3-3 as a positive electrode active material for a lithium secondary battery, a lithium secondary battery was produced in the same manner as in Example 1 to evaluate battery characteristics.

(DSC測定方法) (DSC measurement method)

對於按與實例1相同的順序製作、進行了初期充放電步驟的鋰二次電池，進行電流0.1ItmA、電壓4.3V、15小時的恆定電流恆定電壓充電。 The lithium secondary battery produced in the same order as in Example 1 and subjected to the initial charge and discharge step was subjected to a constant current constant voltage charge of 0.1 ItmA, a voltage of 4.3 V, and 15 hours.

繼而，於露點(dew point)-40℃以下的氬氣箱中將電池拆開，取出正極，以3mmΦ衝壓機(punch)衝壓正極板後，將Al箔與合劑層一起封入至DSC(示差掃描熱量分析)測定用的不鏽鋼製鍋中，供於DSC測定。DSC測定中，將Al₂O₃用於參考(reference)，於氬氣環境中進行室溫至400℃的測定。升溫速度設定為5℃/min。 Then, the battery was disassembled in an argon gas tank having a dew point of -40 ° C or less, the positive electrode was taken out, and the positive electrode plate was punched with a 3 mm Φ punch, and the Al foil and the mixture layer were sealed together to DSC (differential scanning). Thermal analysis) In a stainless steel pot for measurement, it was used for DSC measurement. In the DSC measurement, Al ₂ O _{3 was} used for reference, and the measurement was performed at room temperature to 400 ° C in an argon atmosphere. The heating rate was set to 5 ° C / min.

試樣的填充方法、發熱波峰的讀取方法：依照JIS K 7121_-1987(塑膠的轉移溫度測定方法)來進行。 The method of filling the sample and the method of reading the peak of the heat generation are carried out in accordance with JIS K _7121-1987 (Method for Measuring Transfer Temperature of Plastics).

將充放電循環試驗結果(0.1C電容)、速率比率、DSC發熱波峰溫度示於表3中。 The charge and discharge cycle test results (0.1 C capacitance), rate ratio, and DSC heat peak temperature are shown in Table 3.

如表3所示，對非富含鋰的鋰鎳錳鈷複合氧化物(比 較例3-3)應用Mg的比較例3-2的活性物質的放電電容劣化，並且熱穩定性無變化，相對於此，對富含鋰系的鋰鎳錳鈷複合氧化物(比較例3-1)應用Mg的實例3-1的活性物質的放電電容提高，並且充電狀態下的熱穩定性亦提高。 As shown in Table 3, for non-lithium-rich lithium nickel manganese cobalt composite oxide (ratio Comparative Example 3-3) The discharge capacity of the active material of Comparative Example 3-2 using Mg was deteriorated, and the thermal stability was not changed. On the other hand, the lithium-rich lithium nickel manganese cobalt composite oxide was added (Comparative Example 3) -1) The discharge capacity of the active material of Example 3-1 using Mg was increased, and the thermal stability in the charged state was also improved.

[產業上之可利用性] [Industrial availability]

本發明的鋰二次電池用活性物質由於放電電容大，且高率放電特性優異，故可有效用於電動車用電源、電子機器用電源、電力儲藏用電源等的鋰二次電池。 Since the active material for a lithium secondary battery of the present invention has a large discharge capacity and excellent high-rate discharge characteristics, it can be effectively used for a lithium secondary battery such as an electric vehicle power source, an electronic device power source, or a power storage power source.

雖然本發明已以較佳實施例揭露如上，然其並非用以限定本發明，任何熟習此技藝者，在不脫離本發明之精神和範圍內，當可作些許之更動與潤飾，因此本發明之保護範圍當視後附之申請專利範圍所界定者為準。 While the present invention has been described in its preferred embodiments, the present invention is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

Claims (9)

一種鋰二次電池用活性物質，其含有具有α-NaFeO₂型結晶構造的鋰過渡金屬複合氧化物的固溶體，該鋰二次電池用活性物質的特徵在於：上述固溶體所含有的金屬元素的組成比率滿足Li_1+(x/3)Co_1-x-y-zNi_y/2Mg_z/2Mn_{(2x/3)+(y/2)+(z/2)}(x>0、y>0、z>0、x+y+z<1)，具有可歸屬於空間群P3₁12或R3-m的X射線繞射圖案，由X射線繞射測定所得的(003)面與(114)面或(104)面的繞射波峰的強度比為I₍₀₀₃₎/I₍₁₁₄₎≧1.15或I₍₀₀₃₎/I₍₁₀₄₎≧1.15。 An active material for a lithium secondary battery comprising a solid solution of a lithium transition metal composite oxide having an α-NaFeO ₂ type crystal structure, wherein the active material for a lithium secondary battery is characterized by: The composition ratio of the metal element satisfies Li _1+(x/3) Co _1-xyz Ni _y/2 Mg _z/2 Mn _{(2x/3)+(y/2)+(z/2)} (x>0, y >0, z>0, x+y+z<1), having an X-ray diffraction pattern attributable to the space group P3 ₁ 12 or R3-m, the (003) plane obtained by X-ray diffraction measurement 114) The intensity ratio of the diffraction peak of the face or (104) face is I ₍₀₀₃₎ / I ₍₁₁₄₎ ≧ 1.15 or I ₍₀₀₃₎ / I ₍₁₀₄₎ ≧ 1.15. 一種鋰二次電池用活性物質，其含有具有α-NaFeO₂型結晶構造的鋰過渡金屬複合氧化物的固溶體，該鋰二次電池用活性物質的特徵在於：上述固溶體所含有的金屬元素的組成比率滿足Li_1+(x/3)Co_1-x-y-zNi_y/2Mg_z/2Mn_{(2x/3)+(y/2)+(z/2)}(x>0、y>0、z>0、x+y+z<1)，具有可歸屬於空間群P3₁12或R3-m的X射線繞射圖案，由X射線繞射測定所得的(003)面的繞射波峰的半高寬為0.15°以下，且(114)面或(104)面的繞射波峰的半高寬為0.25°以下。 An active material for a lithium secondary battery comprising a solid solution of a lithium transition metal composite oxide having an α-NaFeO ₂ type crystal structure, wherein the active material for a lithium secondary battery is characterized by: The composition ratio of the metal element satisfies Li _1+(x/3) Co _1-xyz Ni _y/2 Mg _z/2 Mn _{(2x/3)+(y/2)+(z/2)} (x>0, y >0, z>0, x+y+z<1), having an X-ray diffraction pattern attributable to the space group P3 ₁ 12 or R3-m, and the (003) plane obtained by X-ray diffraction measurement The full width at half maximum of the peak is 0.15° or less, and the full width at half maximum of the diffraction peak of the (114) plane or the (104) plane is 0.25° or less. 一種鋰二次電池用活性物質，其含有具有α-NaFeO₂型結晶構造的鋰過渡金屬複合氧化物的固溶體，該鋰二次電池用活性物質的特徵在於：上述固溶體所含有的金屬元素的組成比率滿足Li_1+(x/3)Co_1-x-y-zNi_y/2Mg_z/2Mn_{(2x/3)+(y/2)+(z/2)}(x>0、y>0、z>0、x+y+z<1)，具有可歸屬於空間群P3₁12或R3-m的X射線繞射圖案，由X射線繞射測定所得的(003)面與(114)面或(104)面的繞射波峰的 強度比為I₍₀₀₃₎/I₍₁₁₄₎≧1.15或I₍₀₀₃₎/I₍₁₀₄₎≧1.15，及(003)面的繞射波峰的半高寬為0.15°以下，且(114)面或(104)面的繞射波峰的半高寬為0.25°以下。 An active material for a lithium secondary battery comprising a solid solution of a lithium transition metal composite oxide having an α-NaFeO ₂ type crystal structure, wherein the active material for a lithium secondary battery is characterized by: The composition ratio of the metal element satisfies Li _1+(x/3) Co _1-xyz Ni _y/2 Mg _z/2 Mn _{(2x/3)+(y/2)+(z/2)} (x>0, y >0, z>0, x+y+z<1), having an X-ray diffraction pattern attributable to the space group P3 ₁ 12 or R3-m, the (003) plane obtained by X-ray diffraction measurement 114) The intensity ratio of the diffraction peak of the face or (104) plane is I ₍₀₀₃₎ / I ₍₁₁₄₎ ≧ 1.15 or I ₍₀₀₃₎ / I ₍₁₀₄₎ ≧ 1.15, and the diffraction peak of the (003) plane The full width at half maximum is 0.15° or less, and the full width at half maximum of the diffraction peak of the (114) plane or the (104) plane is 0.25° or less. 如申請專利範圍第1項至第3項中任一項所述之鋰二次電池用活性物質，其中上述鋰過渡金屬複合氧化物的固溶體所含有的金屬元素的組成比率為1/3<x<2/3、0<y<2/3、0<z<0.3。 The active material for a lithium secondary battery according to any one of the first to third aspect, wherein the solid solution of the lithium transition metal composite oxide has a composition ratio of 1/3 of a metal element. <x<2/3, 0<y<2/3, 0<z<0.3. 如申請專利範圍第1項至第3項中任一項所述之鋰二次電池用活性物質，其中上述鋰過渡金屬複合氧化物的固溶體是由Li[Li_1/3Mn_2/3]O₂、LiNi_1/2Mn_1/2O₂、LiCoO₂及LiMg_1/2Mn_1/2O₂四種成分的固溶體構成。 The active material for a lithium secondary battery according to any one of claims 1 to 3, wherein the solid solution of the lithium transition metal composite oxide is Li[Li _1/3 Mn _2/3 a solid solution of four components of O ₂ , LiNi _1/2 Mn _1/2 O ₂ , LiCoO ₂ and LiMg _1/2 Mn _1/2 O ₂ . 如申請專利範圍第1項至第3項中任一項所述之鋰二次電池用活性物質，其中上述鋰過渡金屬複合氧化物的固溶體中，構成的各元素的價數為Li¹⁺、Mn⁴⁺、Ni²⁺、Co³⁺、Mg²⁺。 The active material for a lithium secondary battery according to any one of the first to third aspect, wherein the valence of each element of the solid solution of the lithium transition metal composite oxide is Li ^{1 +} , Mn ⁴⁺ , Ni ²⁺ , Co ³⁺ , Mg ²⁺ . 一種鋰二次電池用電極，含有如申請專利範圍第1項至第3項中任一項所述之鋰二次電池用活性物質。 An electrode for a lithium secondary battery, which comprises the active material for a lithium secondary battery according to any one of claims 1 to 3. 一種鋰二次電池，包含如申請專利範圍第7項所述之鋰二次電池用電極。 A lithium secondary battery comprising the electrode for a lithium secondary battery according to claim 7 of the patent application. 一種鋰二次電池的製造方法，其是採用充電時的正極的最大到達電位為4.3V(vs.Li/Li⁺)以下的充電方法的用以製造如申請專利範圍第8項所述之鋰二次電池的製造方法，其特徵在於包括以下步驟：進行在超過4.3V(vs.Li/Li⁺)且為4.8V(vs.Li/Li⁺)以下的正極電位範圍中出 現的電位變化至少達到相對較平坦的區域的充電。 A method for producing a lithium secondary battery using a charging method in which a maximum reaching potential of a positive electrode during charging is 4.3 V (vs. Li/Li ⁺ ) or less is used to manufacture lithium as described in claim 8 A method of manufacturing a secondary battery, comprising the steps of: performing a potential change occurring in a positive electrode potential range exceeding 4.3 V (vs. Li/Li ⁺ ) and 4.8 V (vs. Li/Li ⁺ ) or less; Recharge to a relatively flat area.