WO2019065287A1 - Lithium ion secondary battery - Google Patents
Lithium ion secondary battery Download PDFInfo
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- WO2019065287A1 WO2019065287A1 PCT/JP2018/034089 JP2018034089W WO2019065287A1 WO 2019065287 A1 WO2019065287 A1 WO 2019065287A1 JP 2018034089 W JP2018034089 W JP 2018034089W WO 2019065287 A1 WO2019065287 A1 WO 2019065287A1
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- ion secondary
- secondary battery
- lithium ion
- positive electrode
- acid ester
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
- H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
- H01M10/0566—Liquid materials
- H01M10/0569—Liquid materials characterised by the solvents
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Definitions
- the present invention relates to a lithium ion secondary battery.
- lithium ion secondary batteries used as a main power source for mobile communication devices and portable electronic devices have features of high electromotive force and high energy density.
- layered compounds such as LiCoO 2 and LiNi 1/3 Mn 1/3 Co 1/3 O 2 and spinel compounds such as LiMn 2 O 4 have been used as positive electrode materials (positive electrode active materials) for lithium ion secondary batteries.
- olivine type compounds represented by LiFePO 4 have attracted attention. It is known that positive electrode materials having an olivine structure have high thermal stability at high temperatures and high safety.
- LiCoPO 4 , LiNiPO 4 and the like have been proposed as phosphoric acid based positive electrode materials capable of realizing high charge and discharge voltage.
- LiCoPO 4 , LiNiPO 4 and the like have been proposed as phosphoric acid based positive electrode materials capable of realizing high charge and discharge voltage.
- sufficient capacity is not obtained.
- vanadium phosphate compounds having a structure of LiVOPO 4 or Li 3 V 2 (PO 4 ) 3 are known as compounds capable of achieving a 4 V-class charge / discharge voltage.
- vanadium phosphate compounds having a structure of LiVOPO 4 or Li 3 V 2 (PO 4 ) 3 are known as compounds capable of achieving a 4 V-class charge / discharge voltage.
- Patent Document 1 reports that, by adding hydrofluoric acid to the electrolytic solution, the reaction with vanadium ions which is a cause of gas generation is caused to suppress the gas generation.
- the inventors of the present invention conducted intensive studies and found that the tap density of the lithium vanadium compound is low, which makes it difficult to increase the density of the positive electrode using the compound, and that the electrolytic solution is not sufficiently impregnated by capillary action. I found it to be the cause. That is, since the non-uniform film is formed by performing the initial charge and discharge in a state where the positive electrode is not sufficiently wet, the cycle characteristics are impaired.
- the present invention has been made in view of the problems of the above-mentioned prior art, and it is an object of the present invention to provide a lithium ion secondary battery capable of improving cycle characteristics.
- a lithium ion secondary battery according to the present invention is a lithium ion secondary battery comprising a positive electrode, a negative electrode, a separator positioned between the positive electrode and the negative electrode, and an electrolytic solution.
- the positive electrode contains a lithium vanadium compound
- the electrolytic solution contains a carboxylic acid ester.
- the carboxylic ester has a sufficiently low viscosity and high wettability, even an electrode containing a lithium vanadium compound rapidly penetrates, thereby forming a uniform film and improving the cycle characteristics. Do.
- the carboxylic acid ester is preferably represented by the following chemical formula (1).
- R 1 and R 2 each represent a linear or branched alkyl group having 1 to 4 carbon atoms or a substituted alkyl group, and the total number of carbon atoms of R 1 and R 2 is 5 or less.
- the carboxylic acid ester is propionic acid ester or acetic acid ester.
- the above-mentioned carboxylic acid ester is contained in the above-mentioned electrolytic solution at 50% by volume or more and 90% by volume or less.
- Lithium-ion secondary battery according to the present invention preferably further the lithium vanadium compound is LiVOPO 4.
- a lithium ion secondary battery capable of improving cycle characteristics is provided.
- the lithium ion secondary battery 100 As shown in FIG. 1, the lithium ion secondary battery 100 according to this embodiment is disposed adjacent to each other between the plate-like negative electrode 20 and the plate-like positive electrode 10 facing each other, and between the negative electrode 20 and the positive electrode 10. And an electrolytic solution containing lithium ions, a case 50 for accommodating these in a sealed state, and one end of the negative electrode 20 are electrically connected. It has a lead 62 whose other end protrudes outside the case, and a lead 60 whose one end is electrically connected to the positive electrode 10 and whose other end protrudes outside the case.
- the positive electrode 10 has a positive electrode current collector 12 and a positive electrode active material layer 14 formed on the positive electrode current collector 12. Further, the negative electrode 20 has a negative electrode current collector 22 and a negative electrode active material layer 24 formed on the negative electrode current collector 22. The separator 18 is located between the negative electrode active material layer 24 and the positive electrode active material layer 14.
- the positive electrode according to the present embodiment contains a lithium vanadium compound.
- the positive electrode current collector 12 may be any conductive plate material, and for example, aluminum or an alloy thereof, or a thin metal plate (metal foil) such as stainless steel can be used.
- the positive electrode active material layer 14 is mainly composed of a positive electrode active material, a positive electrode binder, and a positive electrode conductive aid.
- the positive electrode active material according to the present embodiment contains a lithium vanadium compound.
- the impregnation of the electrolyte solution by capillary action sufficiently proceeds, a uniform film is formed, and the cycle characteristics are improved.
- the effect of improving the cycle characteristics when combined with the electrolytic solution according to the present embodiment, the effect of improving the cycle characteristics can be further obtained.
- the positive electrode binder bonds the positive electrode active materials to one another, and also bonds the positive electrode active material layer 14 and the positive electrode current collector 12.
- the binder may be any one as long as the above-mentioned bonding is possible, for example, a fluorine resin such as polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE), cellulose, styrene butadiene rubber, ethylene / propylene rubber, polyimide Resin, polyamide imide resin, etc. may be used.
- PVDF polyvinylidene fluoride
- PTFE polytetrafluoroethylene
- cellulose cellulose
- styrene butadiene rubber styrene butadiene rubber
- ethylene / propylene rubber polyimide Resin
- polyamide imide resin etc.
- an electron conductive conductive polymer or an ion conductive conductive polymer may be used as the binder.
- the electron conductive conductive polymer examples include polyacetylene, polythiophene, polyaniline and the like.
- the ion conductive conductive polymer for example, those obtained by combining a polyether type polymer compound such as polyethylene oxide or polypropylene oxide with a lithium salt such as LiClO 4 , LiBF 4 or LiPF 6 are listed.
- the content of the binder in the positive electrode active material layer 14 is not particularly limited, but when it is added, it is preferably 0.5 to 5 parts by mass with respect to the mass of the positive electrode active material.
- the conductive aid for the positive electrode is not particularly limited as long as it can improve the conductivity of the positive electrode active material layer 14, and a known conductive aid can be used. Examples thereof include carbon-based materials such as graphite and carbon black, fine powders of metals such as copper, nickel, stainless steel and iron, and conductive oxides such as ITO.
- the negative electrode current collector 22 may be any conductive plate material, and for example, a thin metal plate such as copper (metal foil) can be used.
- the negative electrode active material layer 24 is mainly composed of a negative electrode active material, a binder for the negative electrode, and a conductive additive for the negative electrode.
- the negative electrode active material is not particularly limited as long as it can reversibly advance absorption and release of lithium ions and desorption and insertion (intercalation) of lithium ions, and known electrode active materials can be used.
- carbon-based materials such as graphite and hard carbon
- silicon-based materials such as silicon oxide (SiO x ) metal silicon (Si)
- metal oxides such as lithium titanate (LTO)
- metal materials such as lithium, tin and zinc Can be mentioned.
- the negative electrode active material layer 24 may further contain a negative electrode binder and a negative electrode conductive aid.
- the negative electrode binder is not particularly limited, and the same positive electrode binder as described above can be used.
- the electrolytic solution according to the present embodiment contains a carboxylic acid ester.
- the carboxylic ester has a sufficiently low viscosity and high wettability, even an electrode containing a lithium vanadium compound rapidly penetrates, thereby forming a uniform film and improving the cycle characteristics. Do.
- the carboxylic acid ester is preferably represented by a chemical formula (1), and more preferably a propionic acid ester or an acetic acid ester.
- the carboxylic acid ester is preferably contained in the electrolytic solution in an amount of 50% by volume or more and 90% by volume or less.
- the electrolyte solution which concerns on this embodiment can use the solvent generally used for the lithium ion secondary battery other than the said carboxylic ester.
- the solvent is not particularly limited, and examples thereof include cyclic carbonate compounds such as ethylene carbonate (EC) and propylene carbonate (PC), linear carbonate compounds such as diethyl carbonate (DEC) and ethyl methyl carbonate (EMC), and the like. It can be mixed and used in the ratio of
- the electrolyte is not particularly limited as long as it is a lithium salt used as an electrolyte of a lithium ion secondary battery, and examples thereof include inorganic acid anion salts such as LiPF 6 , LiBF 4 and lithium bis oxalate borate, LiCF 3 SO 3 , Organic acid anionic salts such as (CF 3 SO 2 ) 2 NLi and (FSO 2 ) 2 NLi can be used.
- inorganic acid anion salts such as LiPF 6 , LiBF 4 and lithium bis oxalate borate, LiCF 3 SO 3 , Organic acid anionic salts such as (CF 3 SO 2 ) 2 NLi and (FSO 2 ) 2 NLi can be used.
- Example 1 (Production of positive electrode) 85 parts by mass of LiVOPO 4 as a lithium vanadium compound, 5 parts by mass of carbon black and 10 parts by mass of PVDF were dispersed in N-methyl-2-pyrrolidone (NMP) to prepare a slurry for forming a positive electrode active material layer.
- NMP N-methyl-2-pyrrolidone
- the slurry was applied to one surface of a 20 ⁇ m thick aluminum metal foil so that the coating amount of the positive electrode active material was 9.0 mg / cm 2, and dried at 100 ° C. to form a positive electrode active material layer. Then, it pressure-molded by the roller press, and produced the positive electrode.
- Example 2 A lithium ion secondary battery for evaluation of Example 2 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
- Example 3 A lithium ion secondary battery for evaluation of Example 3 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
- Example 4 A lithium ion secondary battery for evaluation of Example 4 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
- Example 5 A lithium ion secondary battery for evaluation of Example 5 was produced as in Example 2 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
- Example 6 A lithium ion secondary battery for evaluation of Example 6 was produced as in Example 2 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
- Example 7 A lithium ion secondary battery for evaluation of Example 7 was produced in the same manner as in Example 2 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
- Example 8 A lithium ion secondary battery for evaluation of Example 8 was produced in the same manner as in Example 2 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
- Example 9 A lithium ion secondary battery for evaluation of Example 9 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
- Example 10 A lithium ion secondary battery for evaluation of Example 10 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
- Example 11 A lithium ion secondary battery for evaluation of Example 11 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
- Example 12 A lithium ion secondary battery for evaluation of Example 12 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
- Example 13 A lithium ion secondary battery for evaluation of Example 13 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
- Example 14 A lithium ion secondary battery for evaluation of Example 14 was produced in the same manner as Example 10 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
- Example 15 A lithium ion secondary battery for evaluation of Example 15 was produced in the same manner as in Example 10 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
- Example 16 A lithium ion secondary battery for evaluation of Example 16 was produced in the same manner as Example 10 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
- Example 17 A lithium ion secondary battery for evaluation of Example 17 was produced as in Example 10 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
- Example 18 A lithium ion secondary battery for evaluation of Example 18 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
- Example 19 A lithium ion secondary battery for evaluation of Example 19 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
- Example 20 A lithium ion secondary battery for evaluation of Example 20 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
- Example 21 A lithium ion secondary battery for evaluation of Example 21 was produced in the same manner as in Example 1 except that the lithium vanadium compound used in producing the positive electrode was changed as shown in Table 1.
- Example 22 A lithium ion secondary battery for evaluation of Example 22 was produced in the same manner as in Example 1 except that the lithium vanadium compound used in producing the positive electrode was changed as shown in Table 1.
- Example 23 A lithium ion secondary battery for evaluation of Example 23 was produced in the same manner as in Example 2 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
- Example 24 The composition of the slurry for forming a positive electrode active material layer produced in manufacturing the positive electrode, LiVOPO 4 70 parts by weight LiCoO 2 15 parts by weight of carbon black 5 parts by mass, and PVDF10 parts by mass to prepare a positive electrode.
- a lithium ion secondary battery for evaluation of Example 24 was produced in the same manner as Example 1 except for the above.
- Example 25 The composition of the slurry for forming the positive electrode active material layer prepared in the preparation of the positive electrode was 70 parts by mass of LiVOPO 4 , 15 parts by mass of LiNi 0.80 Co 0.15 Al 0.05 O 2 , 5 parts by mass of carbon black, 10 parts by mass of PVDF As a part, a positive electrode was produced.
- a lithium ion secondary battery for evaluation of Example 25 was produced in the same manner as Example 1 except for the above.
- Comparative Example 1 A lithium ion secondary battery for evaluation of Comparative Example 1 was produced as in Example 1 except that the composition ratio of the electrolytic solution was changed as shown in Table 1 without using a carboxylic acid ester.
- Comparative Example 2 A lithium ion secondary battery for evaluation of Comparative Example 2 was produced as in Example 1 except that the composition ratio of the electrolytic solution was changed as shown in Table 1 without using a carboxylic acid ester.
- Comparative Example 3 A lithium ion secondary battery for evaluation of Comparative Example 3 was produced in the same manner as in Example 21 except that the composition ratio of the electrolytic solution was changed as shown in Table 1 without using a carboxylic acid ester.
- Comparative Example 4 A lithium ion secondary battery for evaluation of Comparative Example 4 was produced in the same manner as in Example 22 except that the composition ratio of the electrolytic solution was changed as shown in Table 1 without using a carboxylic acid ester.
- Comparative Example 5 The composition of the slurry for forming a positive electrode active material layer produced in manufacturing the positive electrode, LiCoO 2 85 parts by weight of carbon black 5 parts by mass, and PVDF10 parts by mass to prepare a positive electrode.
- a lithium ion secondary battery for evaluation of Comparative Example 5 was produced in the same manner as Example 2 except for the above.
- Comparative Example 6 The composition of the slurry for forming the positive electrode active material layer prepared in the preparation of the positive electrode was 85 parts by mass of LiNi 0.80 Co 0.15 Al 0.05 O 2 , 5 parts by mass of carbon black, and 10 parts by mass of PVDF to prepare a positive electrode. did.
- a lithium ion secondary battery for evaluation of Comparative Example 6 was produced in the same manner as Example 2 except for the above.
- Comparative Example 7 The composition of the slurry for forming the positive electrode active material layer prepared in the preparation of the positive electrode was 70 parts by mass of LiFePO 4 , 15 parts by mass of LiNi 0.80 Co 0.15 Al 0.05 O 2 , 5 parts by mass of carbon black, 10 parts by mass of PVDF As a part, a positive electrode was produced. A lithium ion secondary battery for evaluation of Comparative Example 7 was produced in the same manner as Example 1 except for the above.
- Examples 1 to 25 improved the capacity retention rate after 300 cycles as compared with Comparative Examples 1 and 2 in which no carboxylic acid ester was used.
- Example 24 and Example 25 and Comparative Example 5 From the results of Example 24 and Example 25 and Comparative Example 5, it was confirmed that when the lithium vanadium compound is used in addition to the conventional positive electrode active material, the improvement effect of the capacity retention rate after 300 cycles can be obtained.
- a lithium ion secondary battery capable of improving cycle characteristics is provided.
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Abstract
The present invention provides a lithium ion secondary battery which is capable of improving cycle characteristics. This lithium ion secondary battery is provided with a positive electrode, a negative electrode, a separator positioned between the positive electrode and the negative electrode, and an electrolyte. The lithium ion secondary battery is characterized in that: the positive electrode includes a lithium vanadium compound; and the electrolyte includes a carboxylic acid ester.
Description
本発明は、リチウムイオン二次電池に関する。
The present invention relates to a lithium ion secondary battery.
近年、移動体通信機器、携帯電子機器の主電源として利用されているリチウムイオン二次電池は、起電力が高く、高エネルギー密度であるという特長を有している。
In recent years, lithium ion secondary batteries used as a main power source for mobile communication devices and portable electronic devices have features of high electromotive force and high energy density.
従来、リチウムイオン二次電池の正極材料（正極活物質）としてＬｉＣｏＯ２やＬｉＮｉ１／３Ｍｎ１／３Ｃｏ１／３Ｏ２等の層状化合物やＬｉＭｎ２Ｏ４等のスピネル化合物が用いられてきた。近年では、ＬｉＦｅＰＯ４に代表されるオリビン型構造の化合物が注目されている。オリビン構造を有する正極材料は高温での熱安定性が高く、安全性が高いことが知られている。
Conventionally, layered compounds such as LiCoO 2 and LiNi 1/3 Mn 1/3 Co 1/3 O 2 and spinel compounds such as LiMn 2 O 4 have been used as positive electrode materials (positive electrode active materials) for lithium ion secondary batteries. The In recent years, olivine type compounds represented by LiFePO 4 have attracted attention. It is known that positive electrode materials having an olivine structure have high thermal stability at high temperatures and high safety.
しかし、ＬｉＦｅＰＯ４を用いたリチウムイオン二次電池は、その充放電電圧が３．５Ｖ程度と低く、エネルギー密度が低くなるという欠点を有する。そのため、高い充放電電圧を実現し得るリン酸系正極材料として、ＬｉＣｏＰＯ４やＬｉＮｉＰＯ４等が提案されている。しかし、これらの正極材料を用いたリチウムイオン二次電池においても、十分な容量が得られていないのが現状である。
However, a lithium ion secondary battery using LiFePO 4 has a disadvantage that the charge and discharge voltage is as low as about 3.5 V and the energy density is low. Therefore, LiCoPO 4 , LiNiPO 4 and the like have been proposed as phosphoric acid based positive electrode materials capable of realizing high charge and discharge voltage. However, even in lithium ion secondary batteries using these positive electrode materials, at present, sufficient capacity is not obtained.
上記リン酸系正極材料の中でも４Ｖ級の充放電電圧を実現し得る化合物として、ＬｉＶＯＰＯ４やＬｉ３Ｖ２（ＰＯ４）３の構造を持つバナジウムホスフェート化合物が知られている。 しかしながら、これらの化合物ではガス発生が顕著という問題が存在し、特に金属ラミネート外装体を用いた電池では形状安定性が損なわれてしまう。
Among the above-described phosphoric acid-based positive electrode materials, vanadium phosphate compounds having a structure of LiVOPO 4 or Li 3 V 2 (PO 4 ) 3 are known as compounds capable of achieving a 4 V-class charge / discharge voltage. However, in these compounds, there is a problem that gas generation is remarkable, and in particular, in a battery using a metal laminate outer package, shape stability is lost.
そこで、特許文献１では電解液中にフッ酸を加えることで、ガス発生の原因となるバナジウムイオンと反応させ、ガス発生を抑制させることが報告されている。
Therefore, Patent Document 1 reports that, by adding hydrofluoric acid to the electrolytic solution, the reaction with vanadium ions which is a cause of gas generation is caused to suppress the gas generation.
しかしながら、いまだ諸特性は満足されず、特にサイクル特性の改善が求められている。
However, various properties are not satisfied yet, and in particular, improvement of cycle characteristics is required.
発明者らは鋭意研究の結果、リチウムバナジウム化合物のタップ密度が低いために、上記化合物を使用した正極の密度が上がりにくく、毛細管現象による電解液の含浸が不十分であることがサイクル特性悪化の原因であることを見出した。すなわち、正極が十分に濡れていない状態で初回充放電を行われることで不均一な皮膜が形成されるため、サイクル特性が損なわれてしまう。
The inventors of the present invention conducted intensive studies and found that the tap density of the lithium vanadium compound is low, which makes it difficult to increase the density of the positive electrode using the compound, and that the electrolytic solution is not sufficiently impregnated by capillary action. I found it to be the cause. That is, since the non-uniform film is formed by performing the initial charge and discharge in a state where the positive electrode is not sufficiently wet, the cycle characteristics are impaired.
本発明は上記従来技術の有する課題に鑑みてなされたものであり、サイクル特性を改善することが可能なリチウムイオン二次電池を提供することを目的とする。
The present invention has been made in view of the problems of the above-mentioned prior art, and it is an object of the present invention to provide a lithium ion secondary battery capable of improving cycle characteristics.
上記課題を解決するため、本発明に係るリチウムイオン二次電池は、正極と、負極と、上記正極と上記負極の間に位置するセパレータと、電解液とを備えるリチウムイオン二次電池であって、上記正極がリチウムバナジウム化合物を含み、上記電解液がカルボン酸エステルを含むことを特徴とする。
In order to solve the above problems, a lithium ion secondary battery according to the present invention is a lithium ion secondary battery comprising a positive electrode, a negative electrode, a separator positioned between the positive electrode and the negative electrode, and an electrolytic solution. The positive electrode contains a lithium vanadium compound, and the electrolytic solution contains a carboxylic acid ester.
これによれば、カルボン酸エステルは十分粘度が低いことに加え、濡れ性が高いため、リチウムバナジウム化合物を含む電極であっても速やかに浸透するため、均一な皮膜が形成され、サイクル特性が改善する。
According to this, since the carboxylic ester has a sufficiently low viscosity and high wettability, even an electrode containing a lithium vanadium compound rapidly penetrates, thereby forming a uniform film and improving the cycle characteristics. Do.
本発明に係るリチウムイオン二次電池はさらに、上記カルボン酸エステルが、下記化学式（１）で表されることが好ましい。
（ここで、Ｒ１およびＲ２は炭素数１～４の直鎖状または分岐状のアルキル基または置換アルキル基であり、Ｒ１とＲ２の炭素数の合計が５以下である。） Further, in the lithium ion secondary battery according to the present invention, the carboxylic acid ester is preferably represented by the following chemical formula (1).
(Here, R 1 and R 2 each represent a linear or branched alkyl group having 1 to 4 carbon atoms or a substituted alkyl group, and the total number of carbon atoms of R 1 and R 2 is 5 or less.)
（ここで、Ｒ１およびＲ２は炭素数１～４の直鎖状または分岐状のアルキル基または置換アルキル基であり、Ｒ１とＲ２の炭素数の合計が５以下である。） Further, in the lithium ion secondary battery according to the present invention, the carboxylic acid ester is preferably represented by the following chemical formula (1).
(Here, R 1 and R 2 each represent a linear or branched alkyl group having 1 to 4 carbon atoms or a substituted alkyl group, and the total number of carbon atoms of R 1 and R 2 is 5 or less.)
これによれば、カルボン酸エステルとして好適であり、サイクル特性が更に改善する。
According to this, it is suitable as a carboxylic acid ester, and the cycle characteristics are further improved.
本発明に係るリチウムイオン二次電池はさらに、上記カルボン酸エステルが、プロピオン酸エステルまたは酢酸エステルであることが好ましい。
In the lithium ion secondary battery according to the present invention, preferably, the carboxylic acid ester is propionic acid ester or acetic acid ester.
これによれば、カルボン酸エステルとして好適であり、サイクル特性が更に改善する。
According to this, it is suitable as a carboxylic acid ester, and the cycle characteristics are further improved.
本発明に係るリチウムイオン二次電池はさらに、上記カルボン酸エステルが、上記電解液中に５０体積％以上９０体積％以下含まれることが好ましい。
In the lithium ion secondary battery according to the present invention, preferably, the above-mentioned carboxylic acid ester is contained in the above-mentioned electrolytic solution at 50% by volume or more and 90% by volume or less.
これによれば、カルボン酸エステルの比率として好適であり、サイクル特性が更に改善する。
According to this, it is suitable as a ratio of carboxylic acid ester, and cycle characteristics are further improved.
本発明に係るリチウムイオン二次電池はさらに、上記リチウムバナジウム化合物がＬｉＶＯＰＯ４であることが好ましい。
Lithium-ion secondary battery according to the present invention preferably further the lithium vanadium compound is LiVOPO 4.
本発明によれば、サイクル特性を改善することが可能なリチウムイオン二次電池が提供される。
According to the present invention, a lithium ion secondary battery capable of improving cycle characteristics is provided.
以下、図面を参照しながら本発明に係る好適な実施形態について説明する。なお、本発明は以下の実施形態に限定されるものではない。また以下に記載した構成要素には、当業者が容易に想到できるもの、実質的に同一のものが含まれる。さらに以下に記載した構成要素は、適宜組み合わせることができる。
Hereinafter, preferred embodiments according to the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments. Further, the components described below include those which can be easily conceived by those skilled in the art and those substantially the same. Furthermore, the components described below can be combined as appropriate.
＜リチウムイオン二次電池＞
図１に示すように、本実施形態に係るリチウムイオン二次電池１００は、互いに対向する板状の負極２０及び板状の正極１０と、負極２０と正極１０との間に隣接して配置される板状のセパレータ１８と、を備える積層体３０と、リチウムイオンを含む電解質溶液と、これらを密閉した状態で収容するケース５０と、負極２０に一方の端部が電気的に接続されると共に他方の端部がケースの外部に突出されるリード６２と、正極１０に一方の端部が電気的に接続されると共に他方の端部がケースの外部に突出されるリード６０とを備える。 <Lithium ion secondary battery>
As shown in FIG. 1, the lithium ionsecondary battery 100 according to this embodiment is disposed adjacent to each other between the plate-like negative electrode 20 and the plate-like positive electrode 10 facing each other, and between the negative electrode 20 and the positive electrode 10. And an electrolytic solution containing lithium ions, a case 50 for accommodating these in a sealed state, and one end of the negative electrode 20 are electrically connected. It has a lead 62 whose other end protrudes outside the case, and a lead 60 whose one end is electrically connected to the positive electrode 10 and whose other end protrudes outside the case.
図１に示すように、本実施形態に係るリチウムイオン二次電池１００は、互いに対向する板状の負極２０及び板状の正極１０と、負極２０と正極１０との間に隣接して配置される板状のセパレータ１８と、を備える積層体３０と、リチウムイオンを含む電解質溶液と、これらを密閉した状態で収容するケース５０と、負極２０に一方の端部が電気的に接続されると共に他方の端部がケースの外部に突出されるリード６２と、正極１０に一方の端部が電気的に接続されると共に他方の端部がケースの外部に突出されるリード６０とを備える。 <Lithium ion secondary battery>
As shown in FIG. 1, the lithium ion
正極１０は、正極集電体１２と、正極集電体１２上に形成された正極活物質層１４と、を有する。また、負極２０は、負極集電体２２と、負極集電体２２上に形成された負極活物質層２４と、を有する。セパレータ１８は、負極活物質層２４と正極活物質層１４との間に位置している。
The positive electrode 10 has a positive electrode current collector 12 and a positive electrode active material layer 14 formed on the positive electrode current collector 12. Further, the negative electrode 20 has a negative electrode current collector 22 and a negative electrode active material layer 24 formed on the negative electrode current collector 22. The separator 18 is located between the negative electrode active material layer 24 and the positive electrode active material layer 14.
＜正極＞
本実施形態に係る正極は、リチウムバナジウム化合物を含むものである。
（正極集電体）
正極集電体１２は、導電性の板材であればよく、例えば、アルミニウム又はそれらの合金、ステンレス等の金属薄板（金属箔）を用いることができる。 <Positive electrode>
The positive electrode according to the present embodiment contains a lithium vanadium compound.
(Positive current collector)
The positive electrodecurrent collector 12 may be any conductive plate material, and for example, aluminum or an alloy thereof, or a thin metal plate (metal foil) such as stainless steel can be used.
本実施形態に係る正極は、リチウムバナジウム化合物を含むものである。
（正極集電体）
正極集電体１２は、導電性の板材であればよく、例えば、アルミニウム又はそれらの合金、ステンレス等の金属薄板（金属箔）を用いることができる。 <Positive electrode>
The positive electrode according to the present embodiment contains a lithium vanadium compound.
(Positive current collector)
The positive electrode
（正極活物質層）
正極活物質層１４は、正極活物質、正極用バインダー、および正極用導電助剤から主に構成されるものである。 (Positive electrode active material layer)
The positive electrodeactive material layer 14 is mainly composed of a positive electrode active material, a positive electrode binder, and a positive electrode conductive aid.
正極活物質層１４は、正極活物質、正極用バインダー、および正極用導電助剤から主に構成されるものである。 (Positive electrode active material layer)
The positive electrode
（正極活物質）
本実施形態に係る正極活物質は、リチウムバナジウム化合物を含む。 (Positive electrode active material)
The positive electrode active material according to the present embodiment contains a lithium vanadium compound.
本実施形態に係る正極活物質は、リチウムバナジウム化合物を含む。 (Positive electrode active material)
The positive electrode active material according to the present embodiment contains a lithium vanadium compound.
上記正極活物質と、本実施形態に係る電解液を組み合わせると、毛細管現象による電解液の含浸が十分に進み、均一な皮膜が形成され、サイクル特性が改善する。
When the positive electrode active material and the electrolyte solution according to the present embodiment are combined, the impregnation of the electrolyte solution by capillary action sufficiently proceeds, a uniform film is formed, and the cycle characteristics are improved.
本実施形態に係る正極活物質はさらに、Ｌｉａ（Ｍ）ｂ（ＰＯ４）ｃ（ただし、Ｍ＝ＶＯまたはＶ、かつ、０．９≦ａ≦３．３、０．９≦ｂ≦２．２、０．９≦ｃ≦３．３）であることが好ましく、ＬｉＶＯＰＯ４であることがより好ましい。
The positive electrode active material according to the present embodiment further includes Li a (M) b (PO 4 ) c (where M = VO or V, and 0.9 ≦ a ≦ 3.3, 0.9 ≦ b ≦ 2). 2. 0.9 ≦ c ≦ 3.3) is preferable, and LiVOPO 4 is more preferable.
上記正極活物質を使用した正極の場合、本実施形態に係る電解液と組み合わせた際に、よりサイクル特性の改善効果が得られる。
In the case of the positive electrode using the above-mentioned positive electrode active material, when combined with the electrolytic solution according to the present embodiment, the effect of improving the cycle characteristics can be further obtained.
（正極用バインダー）
正極用バインダーは正極活物質同士を結合すると共に、正極活物質層１４と正極用集電体１２とを結合している。バインダーは、上述の結合が可能なものであればよく、例えば、ポリフッ化ビニリデン（ＰＶＤＦ）、ポリテトラフルオロエチレン（ＰＴＦＥ）等のフッ素樹脂や、セルロース、スチレン・ブタジエンゴム、エチレン・プロピレンゴム、ポリイミド樹脂、ポリアミドイミド樹脂等を用いてもよい。また、バインダーとして電子伝導性の導電性高分子やイオン伝導性の導電性高分子を用いてもよい。電子伝導性の導電性高分子としては、例えば、ポリアセチレン、ポリチオフェン、ポリアニリン等が挙げられる。イオン伝導性の導電性高分子としては、例えば、ポリエチレンオキシド、ポリプロピレンオキシド等のポリエーテル系高分子化合物と、ＬｉＣｌＯ４、ＬｉＢＦ４、ＬｉＰＦ６等のリチウム塩とを複合化させたもの等が挙げられる。 (Binder for positive electrode)
The positive electrode binder bonds the positive electrode active materials to one another, and also bonds the positive electrodeactive material layer 14 and the positive electrode current collector 12. The binder may be any one as long as the above-mentioned bonding is possible, for example, a fluorine resin such as polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE), cellulose, styrene butadiene rubber, ethylene / propylene rubber, polyimide Resin, polyamide imide resin, etc. may be used. In addition, an electron conductive conductive polymer or an ion conductive conductive polymer may be used as the binder. Examples of the electron conductive conductive polymer include polyacetylene, polythiophene, polyaniline and the like. As the ion conductive conductive polymer, for example, those obtained by combining a polyether type polymer compound such as polyethylene oxide or polypropylene oxide with a lithium salt such as LiClO 4 , LiBF 4 or LiPF 6 are listed. Be
正極用バインダーは正極活物質同士を結合すると共に、正極活物質層１４と正極用集電体１２とを結合している。バインダーは、上述の結合が可能なものであればよく、例えば、ポリフッ化ビニリデン（ＰＶＤＦ）、ポリテトラフルオロエチレン（ＰＴＦＥ）等のフッ素樹脂や、セルロース、スチレン・ブタジエンゴム、エチレン・プロピレンゴム、ポリイミド樹脂、ポリアミドイミド樹脂等を用いてもよい。また、バインダーとして電子伝導性の導電性高分子やイオン伝導性の導電性高分子を用いてもよい。電子伝導性の導電性高分子としては、例えば、ポリアセチレン、ポリチオフェン、ポリアニリン等が挙げられる。イオン伝導性の導電性高分子としては、例えば、ポリエチレンオキシド、ポリプロピレンオキシド等のポリエーテル系高分子化合物と、ＬｉＣｌＯ４、ＬｉＢＦ４、ＬｉＰＦ６等のリチウム塩とを複合化させたもの等が挙げられる。 (Binder for positive electrode)
The positive electrode binder bonds the positive electrode active materials to one another, and also bonds the positive electrode
正極活物質層１４中のバインダーの含有量は特に限定されないが、添加する場合には正極活物質の質量に対して０．５～５質量部であることが好ましい。
The content of the binder in the positive electrode active material layer 14 is not particularly limited, but when it is added, it is preferably 0.5 to 5 parts by mass with respect to the mass of the positive electrode active material.
（正極用導電助剤）
正極用導電助剤としては、正極活物質層１４の導電性を良好にするものであれば特に限定されず、公知の導電助剤を使用できる。例えば、黒鉛、カーボンブラック等の炭素系材料や、銅、ニッケル、ステンレス、鉄等の金属微粉、ＩＴＯ等の導電性酸化物が挙げられる。 (Conductive agent for positive electrode)
The conductive aid for the positive electrode is not particularly limited as long as it can improve the conductivity of the positive electrodeactive material layer 14, and a known conductive aid can be used. Examples thereof include carbon-based materials such as graphite and carbon black, fine powders of metals such as copper, nickel, stainless steel and iron, and conductive oxides such as ITO.
正極用導電助剤としては、正極活物質層１４の導電性を良好にするものであれば特に限定されず、公知の導電助剤を使用できる。例えば、黒鉛、カーボンブラック等の炭素系材料や、銅、ニッケル、ステンレス、鉄等の金属微粉、ＩＴＯ等の導電性酸化物が挙げられる。 (Conductive agent for positive electrode)
The conductive aid for the positive electrode is not particularly limited as long as it can improve the conductivity of the positive electrode
＜負極＞
（負極集電体）
負極集電体２２は、導電性の板材であればよく、例えば、銅等の金属薄板（金属箔）を用いることができる。 <Negative electrode>
(Negative current collector)
The negative electrode current collector 22 may be any conductive plate material, and for example, a thin metal plate such as copper (metal foil) can be used.
（負極集電体）
負極集電体２２は、導電性の板材であればよく、例えば、銅等の金属薄板（金属箔）を用いることができる。 <Negative electrode>
(Negative current collector)
The negative electrode current collector 22 may be any conductive plate material, and for example, a thin metal plate such as copper (metal foil) can be used.
（負極活物質層）
負極活物質層２４は、負極活物質、負極用バインダー、および負極用導電助剤から主に構成されるものである。 (Anode active material layer)
The negative electrode active material layer 24 is mainly composed of a negative electrode active material, a binder for the negative electrode, and a conductive additive for the negative electrode.
負極活物質層２４は、負極活物質、負極用バインダー、および負極用導電助剤から主に構成されるものである。 (Anode active material layer)
The negative electrode active material layer 24 is mainly composed of a negative electrode active material, a binder for the negative electrode, and a conductive additive for the negative electrode.
（負極活物質）
負極活物質としては、リチウムイオンの吸蔵及び放出、リチウムイオンの脱離及び挿入（インターカレーション）を可逆的に進行させることが可能であれば特に限定されず、公知の電極活物質を使用できる。例えば、グラファイト、ハードカーボン等の炭素系材料、酸化シリコン（ＳｉＯｘ）金属シリコン（Ｓｉ）等の珪素系材料、チタン酸リチウム（ＬＴＯ）等の金属酸化物、リチウム、スズ、亜鉛等の金属材料が挙げられる。 (Anode active material)
The negative electrode active material is not particularly limited as long as it can reversibly advance absorption and release of lithium ions and desorption and insertion (intercalation) of lithium ions, and known electrode active materials can be used. . For example, carbon-based materials such as graphite and hard carbon, silicon-based materials such as silicon oxide (SiO x ) metal silicon (Si), metal oxides such as lithium titanate (LTO), and metal materials such as lithium, tin and zinc Can be mentioned.
負極活物質としては、リチウムイオンの吸蔵及び放出、リチウムイオンの脱離及び挿入（インターカレーション）を可逆的に進行させることが可能であれば特に限定されず、公知の電極活物質を使用できる。例えば、グラファイト、ハードカーボン等の炭素系材料、酸化シリコン（ＳｉＯｘ）金属シリコン（Ｓｉ）等の珪素系材料、チタン酸リチウム（ＬＴＯ）等の金属酸化物、リチウム、スズ、亜鉛等の金属材料が挙げられる。 (Anode active material)
The negative electrode active material is not particularly limited as long as it can reversibly advance absorption and release of lithium ions and desorption and insertion (intercalation) of lithium ions, and known electrode active materials can be used. . For example, carbon-based materials such as graphite and hard carbon, silicon-based materials such as silicon oxide (SiO x ) metal silicon (Si), metal oxides such as lithium titanate (LTO), and metal materials such as lithium, tin and zinc Can be mentioned.
負極活物質として金属材料を用いない場合、負極活物質層２４は更に、負極用バインダーおよび負極用導電助剤を含んでいてもよい。
When a metal material is not used as the negative electrode active material, the negative electrode active material layer 24 may further contain a negative electrode binder and a negative electrode conductive aid.
（負極用バインダー）
負極用バインダーとしては特に限定は無く、上記で記載した正極用バインダーと同様のものを用いることができる。 (Binder for negative electrode)
The negative electrode binder is not particularly limited, and the same positive electrode binder as described above can be used.
負極用バインダーとしては特に限定は無く、上記で記載した正極用バインダーと同様のものを用いることができる。 (Binder for negative electrode)
The negative electrode binder is not particularly limited, and the same positive electrode binder as described above can be used.
（負極用導電助剤）
負極用導電助剤としては特に限定は無く、上記で記載した正極用導電助剤と同様のものを用いることができる。 (Conductive additive for negative electrode)
There is no limitation in particular as a conductive support agent for negative electrodes, The thing similar to the conductive support agent for positive electrodes described above can be used.
負極用導電助剤としては特に限定は無く、上記で記載した正極用導電助剤と同様のものを用いることができる。 (Conductive additive for negative electrode)
There is no limitation in particular as a conductive support agent for negative electrodes, The thing similar to the conductive support agent for positive electrodes described above can be used.
＜電解液＞
本実施形態に係る電解液は、カルボン酸エステルを含むものである。 <Electrolyte solution>
The electrolytic solution according to the present embodiment contains a carboxylic acid ester.
本実施形態に係る電解液は、カルボン酸エステルを含むものである。 <Electrolyte solution>
The electrolytic solution according to the present embodiment contains a carboxylic acid ester.
これによれば、カルボン酸エステルは十分粘度が低いことに加え、濡れ性が高いため、リチウムバナジウム化合物を含む電極であっても速やかに浸透するため、均一な皮膜が形成され、サイクル特性が改善する。
According to this, since the carboxylic ester has a sufficiently low viscosity and high wettability, even an electrode containing a lithium vanadium compound rapidly penetrates, thereby forming a uniform film and improving the cycle characteristics. Do.
本実施形態に係る電解液はさらに、上記カルボン酸エステルが、化学式（１）で表されることが好ましく、プロピオン酸エステルまたは酢酸エステルであることがより好ましい。
Further, in the electrolytic solution according to the present embodiment, the carboxylic acid ester is preferably represented by a chemical formula (1), and more preferably a propionic acid ester or an acetic acid ester.
これによれば、カルボン酸エステルとして好適であり、サイクル特性が更に改善する。
According to this, it is suitable as a carboxylic acid ester, and the cycle characteristics are further improved.
本実施形態に係る電解液はさらに、上記カルボン酸エステルが、電解液中に５０体積％以上９０体積％以下含まれることが好ましい。
In the electrolytic solution according to the present embodiment, the carboxylic acid ester is preferably contained in the electrolytic solution in an amount of 50% by volume or more and 90% by volume or less.
これによれば、カルボン酸エステルの比率として好適であり、サイクル特性が更に改善する。また、カルボン酸エステルが５０体積％以上含まれている場合、電解液の粘度は十分に低減され、低粘度化の効果を最大限に得ることが出来る。
According to this, it is suitable as a ratio of carboxylic acid ester, and cycle characteristics are further improved. In addition, when the carboxylic acid ester is contained at 50% by volume or more, the viscosity of the electrolytic solution is sufficiently reduced, and the effect of lowering the viscosity can be obtained to the maximum.
（その他の溶媒）
本実施形態に係る電解液は、上記カルボン酸エステル以外にも一般にリチウムイオン二次電池に用いられている溶媒を用いることが出来る。上記溶媒としては特に限定はなく、例えば、エチレンカーボネート（ＥＣ）、プロピレンカーボネート（ＰＣ）等の環状カーボネート化合物、ジエチルカーボネート（ＤＥＣ）、エチルメチルカーボネート（ＥＭＣ）等の鎖状カーボネート化合物、等を任意の割合で混合して用いることができる。 (Other solvents)
The electrolyte solution which concerns on this embodiment can use the solvent generally used for the lithium ion secondary battery other than the said carboxylic ester. The solvent is not particularly limited, and examples thereof include cyclic carbonate compounds such as ethylene carbonate (EC) and propylene carbonate (PC), linear carbonate compounds such as diethyl carbonate (DEC) and ethyl methyl carbonate (EMC), and the like. It can be mixed and used in the ratio of
本実施形態に係る電解液は、上記カルボン酸エステル以外にも一般にリチウムイオン二次電池に用いられている溶媒を用いることが出来る。上記溶媒としては特に限定はなく、例えば、エチレンカーボネート（ＥＣ）、プロピレンカーボネート（ＰＣ）等の環状カーボネート化合物、ジエチルカーボネート（ＤＥＣ）、エチルメチルカーボネート（ＥＭＣ）等の鎖状カーボネート化合物、等を任意の割合で混合して用いることができる。 (Other solvents)
The electrolyte solution which concerns on this embodiment can use the solvent generally used for the lithium ion secondary battery other than the said carboxylic ester. The solvent is not particularly limited, and examples thereof include cyclic carbonate compounds such as ethylene carbonate (EC) and propylene carbonate (PC), linear carbonate compounds such as diethyl carbonate (DEC) and ethyl methyl carbonate (EMC), and the like. It can be mixed and used in the ratio of
（電解質）
電解質は、リチウムイオン二次電池の電解質として用いられるリチウム塩であれば特に限定は無く、例えば、ＬｉＰＦ６、ＬｉＢＦ４、リチウムビスオキサレートボラート等の無機酸陰イオン塩、ＬｉＣＦ３ＳＯ３、（ＣＦ３ＳＯ２）２ＮＬｉ、（ＦＳＯ２）２ＮＬｉ等の有機酸陰イオン塩等を用いることができる。 (Electrolytes)
The electrolyte is not particularly limited as long as it is a lithium salt used as an electrolyte of a lithium ion secondary battery, and examples thereof include inorganic acid anion salts such as LiPF 6 , LiBF 4 and lithium bis oxalate borate, LiCF 3 SO 3 , Organic acid anionic salts such as (CF 3 SO 2 ) 2 NLi and (FSO 2 ) 2 NLi can be used.
電解質は、リチウムイオン二次電池の電解質として用いられるリチウム塩であれば特に限定は無く、例えば、ＬｉＰＦ６、ＬｉＢＦ４、リチウムビスオキサレートボラート等の無機酸陰イオン塩、ＬｉＣＦ３ＳＯ３、（ＣＦ３ＳＯ２）２ＮＬｉ、（ＦＳＯ２）２ＮＬｉ等の有機酸陰イオン塩等を用いることができる。 (Electrolytes)
The electrolyte is not particularly limited as long as it is a lithium salt used as an electrolyte of a lithium ion secondary battery, and examples thereof include inorganic acid anion salts such as LiPF 6 , LiBF 4 and lithium bis oxalate borate, LiCF 3 SO 3 , Organic acid anionic salts such as (CF 3 SO 2 ) 2 NLi and (FSO 2 ) 2 NLi can be used.
以上、本発明に係る好適な実施形態について説明したが、本発明は上記実施形態に限定されるものではない。
As mentioned above, although the suitable embodiment concerning the present invention was described, the present invention is not limited to the above-mentioned embodiment.
以下、実施例及び比較例に基づいて本発明をより具体的に説明するが、本発明は以下の実施例に限定されるものではない。
Hereinafter, the present invention will be more specifically described based on examples and comparative examples, but the present invention is not limited to the following examples.
［実施例１］
（正極の作製）
リチウムバナジウム化合物としてＬｉＶＯＰＯ４８５質量部、カーボンブラック５質量部、ＰＶＤＦ１０質量部をＮ－メチル－２－ピロリドン（ＮＭＰ）に分散させ、正極活物質層形成用のスラリーを調整した。このスラリーを、厚さ２０μｍのアルミ金属箔の一面に、正極活物質の塗布量が９．０ｍｇ／ｃｍ２となるように塗布し、１００℃で乾燥することで正極活物質層を形成した。その後、ローラープレスによって加圧成形し、正極を作製した。 Example 1
(Production of positive electrode)
85 parts by mass of LiVOPO 4 as a lithium vanadium compound, 5 parts by mass of carbon black and 10 parts by mass of PVDF were dispersed in N-methyl-2-pyrrolidone (NMP) to prepare a slurry for forming a positive electrode active material layer. The slurry was applied to one surface of a 20 μm thick aluminum metal foil so that the coating amount of the positive electrode active material was 9.0 mg / cm 2, and dried at 100 ° C. to form a positive electrode active material layer. Then, it pressure-molded by the roller press, and produced the positive electrode.
（正極の作製）
リチウムバナジウム化合物としてＬｉＶＯＰＯ４８５質量部、カーボンブラック５質量部、ＰＶＤＦ１０質量部をＮ－メチル－２－ピロリドン（ＮＭＰ）に分散させ、正極活物質層形成用のスラリーを調整した。このスラリーを、厚さ２０μｍのアルミ金属箔の一面に、正極活物質の塗布量が９．０ｍｇ／ｃｍ２となるように塗布し、１００℃で乾燥することで正極活物質層を形成した。その後、ローラープレスによって加圧成形し、正極を作製した。 Example 1
(Production of positive electrode)
85 parts by mass of LiVOPO 4 as a lithium vanadium compound, 5 parts by mass of carbon black and 10 parts by mass of PVDF were dispersed in N-methyl-2-pyrrolidone (NMP) to prepare a slurry for forming a positive electrode active material layer. The slurry was applied to one surface of a 20 μm thick aluminum metal foil so that the coating amount of the positive electrode active material was 9.0 mg / cm 2, and dried at 100 ° C. to form a positive electrode active material layer. Then, it pressure-molded by the roller press, and produced the positive electrode.
（負極の作製）
天然黒鉛９０質量部、カーボンブラック５質量部、ＰＶＤＦ５質量部をＮ－メチル－２－ピロリドン（ＮＭＰ）に分散させ、負極活物質層形成用のスラリーを調整した。上記スラリーを、厚さ２０μｍの銅箔の一面に、負極活物質の塗布量が６．０ｍｇ／ｃｍ２となるように塗布し、１００℃で乾燥することで負極活物質層を形成した。その後、ローラープレスによって加圧成形し、負極を作製した。 (Fabrication of negative electrode)
90 parts by mass of natural graphite, 5 parts by mass of carbon black and 5 parts by mass of PVDF were dispersed in N-methyl-2-pyrrolidone (NMP) to prepare a slurry for forming a negative electrode active material layer. The slurry was applied to one surface of a 20 μm thick copper foil so that the coating amount of the negative electrode active material was 6.0 mg / cm 2, and dried at 100 ° C. to form a negative electrode active material layer. Then, it pressure-molded by the roller press, and produced the negative electrode.
天然黒鉛９０質量部、カーボンブラック５質量部、ＰＶＤＦ５質量部をＮ－メチル－２－ピロリドン（ＮＭＰ）に分散させ、負極活物質層形成用のスラリーを調整した。上記スラリーを、厚さ２０μｍの銅箔の一面に、負極活物質の塗布量が６．０ｍｇ／ｃｍ２となるように塗布し、１００℃で乾燥することで負極活物質層を形成した。その後、ローラープレスによって加圧成形し、負極を作製した。 (Fabrication of negative electrode)
90 parts by mass of natural graphite, 5 parts by mass of carbon black and 5 parts by mass of PVDF were dispersed in N-methyl-2-pyrrolidone (NMP) to prepare a slurry for forming a negative electrode active material layer. The slurry was applied to one surface of a 20 μm thick copper foil so that the coating amount of the negative electrode active material was 6.0 mg / cm 2, and dried at 100 ° C. to form a negative electrode active material layer. Then, it pressure-molded by the roller press, and produced the negative electrode.
（電解液の作製）
カルボン酸エステルとしてプロピオン酸メチルを用い、体積比でＥＣ：プロピオン酸エチル＝３０：７０の組成比となるように調整し、これに１．０ｍｏｌ／Ｌの濃度となるようにＬｉＰＦ６を溶解させ、電解液を作製した。 (Preparation of electrolyte)
Using methyl propionate as the carboxylic acid ester, adjust the composition ratio of EC: ethyl propionate = 30: 70 by volume ratio, and dissolve LiPF 6 so that the concentration becomes 1.0 mol / L. , And an electrolyte was prepared.
カルボン酸エステルとしてプロピオン酸メチルを用い、体積比でＥＣ：プロピオン酸エチル＝３０：７０の組成比となるように調整し、これに１．０ｍｏｌ／Ｌの濃度となるようにＬｉＰＦ６を溶解させ、電解液を作製した。 (Preparation of electrolyte)
Using methyl propionate as the carboxylic acid ester, adjust the composition ratio of EC: ethyl propionate = 30: 70 by volume ratio, and dissolve LiPF 6 so that the concentration becomes 1.0 mol / L. , And an electrolyte was prepared.
（評価用リチウムイオン二次電池の作製）
上記で作製した正極および負極と、それらの間にポリエチレン微多孔膜からなるセパレータを挟んでアルミラミネートパックに入れた。このアルミラミネートパックに、上記で作製した電解液を注入した後、真空シールし、評価用リチウムイオン二次電池を作製した。 (Preparation of lithium ion secondary battery for evaluation)
The positive electrode and the negative electrode produced above and a separator made of a polyethylene microporous film were interposed between them and placed in an aluminum laminate pack. The electrolytic solution prepared above was injected into the aluminum laminate pack, and vacuum sealing was performed to prepare a lithium ion secondary battery for evaluation.
上記で作製した正極および負極と、それらの間にポリエチレン微多孔膜からなるセパレータを挟んでアルミラミネートパックに入れた。このアルミラミネートパックに、上記で作製した電解液を注入した後、真空シールし、評価用リチウムイオン二次電池を作製した。 (Preparation of lithium ion secondary battery for evaluation)
The positive electrode and the negative electrode produced above and a separator made of a polyethylene microporous film were interposed between them and placed in an aluminum laminate pack. The electrolytic solution prepared above was injected into the aluminum laminate pack, and vacuum sealing was performed to prepare a lithium ion secondary battery for evaluation.
（３００サイクル後容量維持率の測定）
上記で作製した評価用リチウムイオン二次電池について、二次電池充放電試験装置（北斗電工株式会社製）を用い、充電レート１．０Ｃ（２５℃で定電流充電を行ったときに１時間で充電終了となる電流値）の定電流充電で電池電圧が４．２Ｖとなるまで充電を行い、放電レート１．０Ｃの定電流放電で電池電圧が２．８Ｖとなるまで放電を行った。上記充放電を１サイクルとし、続けて３００サイクルの充放電を行い、３００サイクル後容量維持率（３００サイクル目放電容量／１サイクル目放電容量×１００）を求めた。得られた結果を表１に示す。 (Measurement of capacity retention rate after 300 cycles)
For the lithium ion secondary battery for evaluation prepared above, using a secondary battery charge and discharge test device (manufactured by Hokuto Denko Corporation), charging rate 1.0 C (constant current charging at 25 ° C.) takes 1 hour The battery was charged until the battery voltage reached 4.2 V by constant current charging (the current value at which the charging is completed), and was discharged until the battery voltage reached 2.8 V by constant current discharging at a discharge rate of 1.0C. The charge / discharge cycle was defined as one cycle, followed by 300 cycles of charge / discharge, and after 300 cycles, the capacity retention ratio (300th cycle discharge capacity / first cycle discharge capacity × 100) was determined. The obtained results are shown in Table 1.
上記で作製した評価用リチウムイオン二次電池について、二次電池充放電試験装置（北斗電工株式会社製）を用い、充電レート１．０Ｃ（２５℃で定電流充電を行ったときに１時間で充電終了となる電流値）の定電流充電で電池電圧が４．２Ｖとなるまで充電を行い、放電レート１．０Ｃの定電流放電で電池電圧が２．８Ｖとなるまで放電を行った。上記充放電を１サイクルとし、続けて３００サイクルの充放電を行い、３００サイクル後容量維持率（３００サイクル目放電容量／１サイクル目放電容量×１００）を求めた。得られた結果を表１に示す。 (Measurement of capacity retention rate after 300 cycles)
For the lithium ion secondary battery for evaluation prepared above, using a secondary battery charge and discharge test device (manufactured by Hokuto Denko Corporation), charging rate 1.0 C (constant current charging at 25 ° C.) takes 1 hour The battery was charged until the battery voltage reached 4.2 V by constant current charging (the current value at which the charging is completed), and was discharged until the battery voltage reached 2.8 V by constant current discharging at a discharge rate of 1.0C. The charge / discharge cycle was defined as one cycle, followed by 300 cycles of charge / discharge, and after 300 cycles, the capacity retention ratio (300th cycle discharge capacity / first cycle discharge capacity × 100) was determined. The obtained results are shown in Table 1.
［実施例２］
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例２の評価用リチウムイオン二次電池を作製した。 Example 2
A lithium ion secondary battery for evaluation of Example 2 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例２の評価用リチウムイオン二次電池を作製した。 Example 2
A lithium ion secondary battery for evaluation of Example 2 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
［実施例３］
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例３の評価用リチウムイオン二次電池を作製した。 [Example 3]
A lithium ion secondary battery for evaluation of Example 3 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例３の評価用リチウムイオン二次電池を作製した。 [Example 3]
A lithium ion secondary battery for evaluation of Example 3 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
［実施例４］
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例４の評価用リチウムイオン二次電池を作製した。 Example 4
A lithium ion secondary battery for evaluation of Example 4 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例４の評価用リチウムイオン二次電池を作製した。 Example 4
A lithium ion secondary battery for evaluation of Example 4 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
［実施例５］
電解液の組成比を、表１に示した通りに変更した以外は実施例２と同様として、実施例５の評価用リチウムイオン二次電池を作製した。 [Example 5]
A lithium ion secondary battery for evaluation of Example 5 was produced as in Example 2 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
電解液の組成比を、表１に示した通りに変更した以外は実施例２と同様として、実施例５の評価用リチウムイオン二次電池を作製した。 [Example 5]
A lithium ion secondary battery for evaluation of Example 5 was produced as in Example 2 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
［実施例６］
電解液の組成比を、表１に示した通りに変更した以外は実施例２と同様として、実施例６の評価用リチウムイオン二次電池を作製した。 [Example 6]
A lithium ion secondary battery for evaluation of Example 6 was produced as in Example 2 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
電解液の組成比を、表１に示した通りに変更した以外は実施例２と同様として、実施例６の評価用リチウムイオン二次電池を作製した。 [Example 6]
A lithium ion secondary battery for evaluation of Example 6 was produced as in Example 2 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
［実施例７］
電解液の組成比を、表１に示した通りに変更した以外は実施例２と同様として、実施例７の評価用リチウムイオン二次電池を作製した。 [Example 7]
A lithium ion secondary battery for evaluation of Example 7 was produced in the same manner as in Example 2 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
電解液の組成比を、表１に示した通りに変更した以外は実施例２と同様として、実施例７の評価用リチウムイオン二次電池を作製した。 [Example 7]
A lithium ion secondary battery for evaluation of Example 7 was produced in the same manner as in Example 2 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
［実施例８］
電解液の組成比を、表１に示した通りに変更した以外は実施例２と同様として、実施例８の評価用リチウムイオン二次電池を作製した。 [Example 8]
A lithium ion secondary battery for evaluation of Example 8 was produced in the same manner as in Example 2 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
電解液の組成比を、表１に示した通りに変更した以外は実施例２と同様として、実施例８の評価用リチウムイオン二次電池を作製した。 [Example 8]
A lithium ion secondary battery for evaluation of Example 8 was produced in the same manner as in Example 2 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
［実施例９］
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例９の評価用リチウムイオン二次電池を作製した。 [Example 9]
A lithium ion secondary battery for evaluation of Example 9 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例９の評価用リチウムイオン二次電池を作製した。 [Example 9]
A lithium ion secondary battery for evaluation of Example 9 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
［実施例１０］
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例１０の評価用リチウムイオン二次電池を作製した。 [Example 10]
A lithium ion secondary battery for evaluation of Example 10 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例１０の評価用リチウムイオン二次電池を作製した。 [Example 10]
A lithium ion secondary battery for evaluation of Example 10 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
［実施例１１］
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例１１の評価用リチウムイオン二次電池を作製した。 [Example 11]
A lithium ion secondary battery for evaluation of Example 11 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例１１の評価用リチウムイオン二次電池を作製した。 [Example 11]
A lithium ion secondary battery for evaluation of Example 11 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
［実施例１２］
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例１２の評価用リチウムイオン二次電池を作製した。 [Example 12]
A lithium ion secondary battery for evaluation of Example 12 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例１２の評価用リチウムイオン二次電池を作製した。 [Example 12]
A lithium ion secondary battery for evaluation of Example 12 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
［実施例１３］
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例１３の評価用リチウムイオン二次電池を作製した。 [Example 13]
A lithium ion secondary battery for evaluation of Example 13 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例１３の評価用リチウムイオン二次電池を作製した。 [Example 13]
A lithium ion secondary battery for evaluation of Example 13 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
［実施例１４］
電解液の組成比を、表１に示した通りに変更した以外は実施例１０と同様として、実施例１４の評価用リチウムイオン二次電池を作製した。 Example 14
A lithium ion secondary battery for evaluation of Example 14 was produced in the same manner as Example 10 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
電解液の組成比を、表１に示した通りに変更した以外は実施例１０と同様として、実施例１４の評価用リチウムイオン二次電池を作製した。 Example 14
A lithium ion secondary battery for evaluation of Example 14 was produced in the same manner as Example 10 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
［実施例１５］
電解液の組成比を、表１に示した通りに変更した以外は実施例１０と同様として、実施例１５の評価用リチウムイオン二次電池を作製した。 [Example 15]
A lithium ion secondary battery for evaluation of Example 15 was produced in the same manner as in Example 10 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
電解液の組成比を、表１に示した通りに変更した以外は実施例１０と同様として、実施例１５の評価用リチウムイオン二次電池を作製した。 [Example 15]
A lithium ion secondary battery for evaluation of Example 15 was produced in the same manner as in Example 10 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
［実施例１６］
電解液の組成比を、表１に示した通りに変更した以外は実施例１０と同様として、実施例１６の評価用リチウムイオン二次電池を作製した。 [Example 16]
A lithium ion secondary battery for evaluation of Example 16 was produced in the same manner as Example 10 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
電解液の組成比を、表１に示した通りに変更した以外は実施例１０と同様として、実施例１６の評価用リチウムイオン二次電池を作製した。 [Example 16]
A lithium ion secondary battery for evaluation of Example 16 was produced in the same manner as Example 10 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
［実施例１７］
電解液の組成比を、表１に示した通りに変更した以外は実施例１０と同様として、実施例１７の評価用リチウムイオン二次電池を作製した。 [Example 17]
A lithium ion secondary battery for evaluation of Example 17 was produced as in Example 10 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
電解液の組成比を、表１に示した通りに変更した以外は実施例１０と同様として、実施例１７の評価用リチウムイオン二次電池を作製した。 [Example 17]
A lithium ion secondary battery for evaluation of Example 17 was produced as in Example 10 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
［実施例１８］
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例１８の評価用リチウムイオン二次電池を作製した。 [Example 18]
A lithium ion secondary battery for evaluation of Example 18 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例１８の評価用リチウムイオン二次電池を作製した。 [Example 18]
A lithium ion secondary battery for evaluation of Example 18 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
［実施例１９］
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例１９の評価用リチウムイオン二次電池を作製した。 [Example 19]
A lithium ion secondary battery for evaluation of Example 19 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例１９の評価用リチウムイオン二次電池を作製した。 [Example 19]
A lithium ion secondary battery for evaluation of Example 19 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
［実施例２０］
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例２０の評価用リチウムイオン二次電池を作製した。 [Example 20]
A lithium ion secondary battery for evaluation of Example 20 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
電解液の作製で用いたカルボン酸エステルを、表１に示した通りに変更した以外は実施例１と同様として、実施例２０の評価用リチウムイオン二次電池を作製した。 [Example 20]
A lithium ion secondary battery for evaluation of Example 20 was produced in the same manner as in Example 1 except that the carboxylic acid ester used in the production of the electrolytic solution was changed as shown in Table 1.
［実施例２１］
正極の作製で用いたリチウムバナジウム化合物を、表１に示した通りに変更した以外は実施例１と同様として、実施例２１の評価用リチウムイオン二次電池を作製した。 [Example 21]
A lithium ion secondary battery for evaluation of Example 21 was produced in the same manner as in Example 1 except that the lithium vanadium compound used in producing the positive electrode was changed as shown in Table 1.
正極の作製で用いたリチウムバナジウム化合物を、表１に示した通りに変更した以外は実施例１と同様として、実施例２１の評価用リチウムイオン二次電池を作製した。 [Example 21]
A lithium ion secondary battery for evaluation of Example 21 was produced in the same manner as in Example 1 except that the lithium vanadium compound used in producing the positive electrode was changed as shown in Table 1.
［実施例２２］
正極の作製で用いたリチウムバナジウム化合物を、表１に示した通りに変更した以外は実施例１と同様として、実施例２２の評価用リチウムイオン二次電池を作製した。 Example 22
A lithium ion secondary battery for evaluation of Example 22 was produced in the same manner as in Example 1 except that the lithium vanadium compound used in producing the positive electrode was changed as shown in Table 1.
正極の作製で用いたリチウムバナジウム化合物を、表１に示した通りに変更した以外は実施例１と同様として、実施例２２の評価用リチウムイオン二次電池を作製した。 Example 22
A lithium ion secondary battery for evaluation of Example 22 was produced in the same manner as in Example 1 except that the lithium vanadium compound used in producing the positive electrode was changed as shown in Table 1.
［実施例２３］
電解液の組成比を、表１に示した通りに変更した以外は実施例２と同様として、実施例２３の評価用リチウムイオン二次電池を作製した。 [Example 23]
A lithium ion secondary battery for evaluation of Example 23 was produced in the same manner as in Example 2 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
電解液の組成比を、表１に示した通りに変更した以外は実施例２と同様として、実施例２３の評価用リチウムイオン二次電池を作製した。 [Example 23]
A lithium ion secondary battery for evaluation of Example 23 was produced in the same manner as in Example 2 except that the composition ratio of the electrolytic solution was changed as shown in Table 1.
［実施例２４］
正極の作製で作製した正極活物質層形成用のスラリーの組成を、ＬｉＶＯＰＯ４７０質量部、ＬｉＣｏＯ２１５質量部、カーボンブラック５質量部、ＰＶＤＦ１０質量部とし、正極を作製した。それ以外は実施例１と同様として、実施例２４の評価用リチウムイオン二次電池を作製した。 [Example 24]
The composition of the slurry for forming a positive electrode active material layer produced in manufacturing the positive electrode, LiVOPO 4 70 parts by weight LiCoO 2 15 parts by weight of carbon black 5 parts by mass, and PVDF10 parts by mass to prepare a positive electrode. A lithium ion secondary battery for evaluation of Example 24 was produced in the same manner as Example 1 except for the above.
正極の作製で作製した正極活物質層形成用のスラリーの組成を、ＬｉＶＯＰＯ４７０質量部、ＬｉＣｏＯ２１５質量部、カーボンブラック５質量部、ＰＶＤＦ１０質量部とし、正極を作製した。それ以外は実施例１と同様として、実施例２４の評価用リチウムイオン二次電池を作製した。 [Example 24]
The composition of the slurry for forming a positive electrode active material layer produced in manufacturing the positive electrode, LiVOPO 4 70 parts by weight LiCoO 2 15 parts by weight of carbon black 5 parts by mass, and PVDF10 parts by mass to prepare a positive electrode. A lithium ion secondary battery for evaluation of Example 24 was produced in the same manner as Example 1 except for the above.
［実施例２５］
正極の作製で作製した正極活物質層形成用のスラリーの組成を、ＬｉＶＯＰＯ４７０質量部、ＬｉＮｉ０．８０Ｃｏ０．１５Ａｌ０．０５Ｏ２１５質量部、カーボンブラック５質量部、ＰＶＤＦ１０質量部とし、正極を作製した。それ以外は実施例１と同様として、実施例２５の評価用リチウムイオン二次電池を作製した。 [Example 25]
The composition of the slurry for forming the positive electrode active material layer prepared in the preparation of the positive electrode was 70 parts by mass of LiVOPO 4 , 15 parts by mass of LiNi 0.80 Co 0.15 Al 0.05 O 2 , 5 parts by mass of carbon black, 10 parts by mass of PVDF As a part, a positive electrode was produced. A lithium ion secondary battery for evaluation of Example 25 was produced in the same manner as Example 1 except for the above.
正極の作製で作製した正極活物質層形成用のスラリーの組成を、ＬｉＶＯＰＯ４７０質量部、ＬｉＮｉ０．８０Ｃｏ０．１５Ａｌ０．０５Ｏ２１５質量部、カーボンブラック５質量部、ＰＶＤＦ１０質量部とし、正極を作製した。それ以外は実施例１と同様として、実施例２５の評価用リチウムイオン二次電池を作製した。 [Example 25]
The composition of the slurry for forming the positive electrode active material layer prepared in the preparation of the positive electrode was 70 parts by mass of LiVOPO 4 , 15 parts by mass of LiNi 0.80 Co 0.15 Al 0.05 O 2 , 5 parts by mass of carbon black, 10 parts by mass of PVDF As a part, a positive electrode was produced. A lithium ion secondary battery for evaluation of Example 25 was produced in the same manner as Example 1 except for the above.
［比較例１］
電解液の組成比を、カルボン酸エステルを用いず表１に示した通りに変更した以外は実施例１と同様として、比較例１の評価用リチウムイオン二次電池を作製した。 Comparative Example 1
A lithium ion secondary battery for evaluation of Comparative Example 1 was produced as in Example 1 except that the composition ratio of the electrolytic solution was changed as shown in Table 1 without using a carboxylic acid ester.
電解液の組成比を、カルボン酸エステルを用いず表１に示した通りに変更した以外は実施例１と同様として、比較例１の評価用リチウムイオン二次電池を作製した。 Comparative Example 1
A lithium ion secondary battery for evaluation of Comparative Example 1 was produced as in Example 1 except that the composition ratio of the electrolytic solution was changed as shown in Table 1 without using a carboxylic acid ester.
［比較例２］
電解液の組成比を、カルボン酸エステルを用いず表１に示した通りに変更した以外は実施例１と同様として、比較例２の評価用リチウムイオン二次電池を作製した。 Comparative Example 2
A lithium ion secondary battery for evaluation of Comparative Example 2 was produced as in Example 1 except that the composition ratio of the electrolytic solution was changed as shown in Table 1 without using a carboxylic acid ester.
電解液の組成比を、カルボン酸エステルを用いず表１に示した通りに変更した以外は実施例１と同様として、比較例２の評価用リチウムイオン二次電池を作製した。 Comparative Example 2
A lithium ion secondary battery for evaluation of Comparative Example 2 was produced as in Example 1 except that the composition ratio of the electrolytic solution was changed as shown in Table 1 without using a carboxylic acid ester.
［比較例３］
電解液の組成比を、カルボン酸エステルを用いず表１に示した通りに変更した以外は実施例２１と同様として、比較例３の評価用リチウムイオン二次電池を作製した。 Comparative Example 3
A lithium ion secondary battery for evaluation of Comparative Example 3 was produced in the same manner as in Example 21 except that the composition ratio of the electrolytic solution was changed as shown in Table 1 without using a carboxylic acid ester.
電解液の組成比を、カルボン酸エステルを用いず表１に示した通りに変更した以外は実施例２１と同様として、比較例３の評価用リチウムイオン二次電池を作製した。 Comparative Example 3
A lithium ion secondary battery for evaluation of Comparative Example 3 was produced in the same manner as in Example 21 except that the composition ratio of the electrolytic solution was changed as shown in Table 1 without using a carboxylic acid ester.
［比較例４］
電解液の組成比を、カルボン酸エステルを用いず表１に示した通りに変更した以外は実施例２２と同様として、比較例４の評価用リチウムイオン二次電池を作製した。 Comparative Example 4
A lithium ion secondary battery for evaluation of Comparative Example 4 was produced in the same manner as in Example 22 except that the composition ratio of the electrolytic solution was changed as shown in Table 1 without using a carboxylic acid ester.
電解液の組成比を、カルボン酸エステルを用いず表１に示した通りに変更した以外は実施例２２と同様として、比較例４の評価用リチウムイオン二次電池を作製した。 Comparative Example 4
A lithium ion secondary battery for evaluation of Comparative Example 4 was produced in the same manner as in Example 22 except that the composition ratio of the electrolytic solution was changed as shown in Table 1 without using a carboxylic acid ester.
［比較例５］
正極の作製で作製した正極活物質層形成用のスラリーの組成を、ＬｉＣｏＯ２８５質量部、カーボンブラック５質量部、ＰＶＤＦ１０質量部とし、正極を作製した。それ以外は実施例２と同様として、比較例５の評価用リチウムイオン二次電池を作製した。 Comparative Example 5
The composition of the slurry for forming a positive electrode active material layer produced in manufacturing the positive electrode, LiCoO 2 85 parts by weight of carbon black 5 parts by mass, and PVDF10 parts by mass to prepare a positive electrode. A lithium ion secondary battery for evaluation of Comparative Example 5 was produced in the same manner as Example 2 except for the above.
正極の作製で作製した正極活物質層形成用のスラリーの組成を、ＬｉＣｏＯ２８５質量部、カーボンブラック５質量部、ＰＶＤＦ１０質量部とし、正極を作製した。それ以外は実施例２と同様として、比較例５の評価用リチウムイオン二次電池を作製した。 Comparative Example 5
The composition of the slurry for forming a positive electrode active material layer produced in manufacturing the positive electrode, LiCoO 2 85 parts by weight of carbon black 5 parts by mass, and PVDF10 parts by mass to prepare a positive electrode. A lithium ion secondary battery for evaluation of Comparative Example 5 was produced in the same manner as Example 2 except for the above.
［比較例６］
正極の作製で作製した正極活物質層形成用のスラリーの組成を、ＬｉＮｉ０．８０Ｃｏ０．１５Ａｌ０．０５Ｏ２８５質量部、カーボンブラック５質量部、ＰＶＤＦ１０質量部とし、正極を作製した。それ以外は実施例２と同様として、比較例６の評価用リチウムイオン二次電池を作製した。 Comparative Example 6
The composition of the slurry for forming the positive electrode active material layer prepared in the preparation of the positive electrode was 85 parts by mass of LiNi 0.80 Co 0.15 Al 0.05 O 2 , 5 parts by mass of carbon black, and 10 parts by mass of PVDF to prepare a positive electrode. did. A lithium ion secondary battery for evaluation of Comparative Example 6 was produced in the same manner as Example 2 except for the above.
正極の作製で作製した正極活物質層形成用のスラリーの組成を、ＬｉＮｉ０．８０Ｃｏ０．１５Ａｌ０．０５Ｏ２８５質量部、カーボンブラック５質量部、ＰＶＤＦ１０質量部とし、正極を作製した。それ以外は実施例２と同様として、比較例６の評価用リチウムイオン二次電池を作製した。 Comparative Example 6
The composition of the slurry for forming the positive electrode active material layer prepared in the preparation of the positive electrode was 85 parts by mass of LiNi 0.80 Co 0.15 Al 0.05 O 2 , 5 parts by mass of carbon black, and 10 parts by mass of PVDF to prepare a positive electrode. did. A lithium ion secondary battery for evaluation of Comparative Example 6 was produced in the same manner as Example 2 except for the above.
［比較例７］
正極の作製で作製した正極活物質層形成用のスラリーの組成を、ＬｉＦｅＰＯ４７０質量部、ＬｉＮｉ０．８０Ｃｏ０．１５Ａｌ０．０５Ｏ２１５質量部、カーボンブラック５質量部、ＰＶＤＦ１０質量部とし、正極を作製した。それ以外は実施例１と同様として、比較例７の評価用リチウムイオン二次電池を作製した。 Comparative Example 7
The composition of the slurry for forming the positive electrode active material layer prepared in the preparation of the positive electrode was 70 parts by mass of LiFePO 4 , 15 parts by mass of LiNi 0.80 Co 0.15 Al 0.05 O 2 , 5 parts by mass of carbon black, 10 parts by mass of PVDF As a part, a positive electrode was produced. A lithium ion secondary battery for evaluation of Comparative Example 7 was produced in the same manner as Example 1 except for the above.
正極の作製で作製した正極活物質層形成用のスラリーの組成を、ＬｉＦｅＰＯ４７０質量部、ＬｉＮｉ０．８０Ｃｏ０．１５Ａｌ０．０５Ｏ２１５質量部、カーボンブラック５質量部、ＰＶＤＦ１０質量部とし、正極を作製した。それ以外は実施例１と同様として、比較例７の評価用リチウムイオン二次電池を作製した。 Comparative Example 7
The composition of the slurry for forming the positive electrode active material layer prepared in the preparation of the positive electrode was 70 parts by mass of LiFePO 4 , 15 parts by mass of LiNi 0.80 Co 0.15 Al 0.05 O 2 , 5 parts by mass of carbon black, 10 parts by mass of PVDF As a part, a positive electrode was produced. A lithium ion secondary battery for evaluation of Comparative Example 7 was produced in the same manner as Example 1 except for the above.
実施例２～２５、および比較例１～７で作製した評価用リチウムイオン二次電池について、実施例１と同様に、３００サイクル後容量維持率の測定を行った。結果を表１に示す。
For the lithium ion secondary batteries for evaluation prepared in Examples 2 to 25 and Comparative Examples 1 to 7, measurement of the capacity retention after 300 cycles was performed in the same manner as in Example 1. The results are shown in Table 1.
実施例１～２５はいずれも、カルボン酸エステルを使用しなかった比較例１および２に対し、３００サイクル後容量維持率が改善した。
Examples 1 to 25 improved the capacity retention rate after 300 cycles as compared with Comparative Examples 1 and 2 in which no carboxylic acid ester was used.
実施例１～４、および実施例９～１３の結果から、カルボン酸の総炭素数を５以下とすることで、３００サイクル後容量維持率がより改善する効果が得られることが確認された。
From the results of Examples 1 to 4 and Examples 9 to 13, it was confirmed that by setting the total carbon number of the carboxylic acid to 5 or less, an effect of further improving the capacity retention rate after 300 cycles can be obtained.
実施例１８～２０の結果から、カルボン酸エステルとしてプロピオン酸エステルまたは酢酸エステルを使用することで、３００サイクル後容量維持率がより改善する効果が得られることが確認された。
From the results of Examples 18 to 20, it was confirmed that the use of propionic acid ester or acetic acid ester as the carboxylic acid ester has the effect of further improving the capacity retention after 300 cycles.
実施例５～８、および実施例１４～１７の結果から、電解液の組成を最適化することで、３００サイクル後容量維持率がより改善する効果が得られることが確認された。
From the results of Examples 5 to 8 and Examples 14 to 17, it was confirmed that the effect of further improving the capacity retention after 300 cycles can be obtained by optimizing the composition of the electrolytic solution.
実施例２２および２３と、比較例３および４の結果から、リチウムバナジウム化合物としてＬｉＶＯＰＯ４を用いた場合、３００サイクル後容量維持率のより高い改善効果が得られることが確認された。
From the results of Examples 22 and 23 and Comparative Examples 3 and 4, it was confirmed that a higher improvement effect of the capacity retention after 300 cycles can be obtained when LiVOPO 4 is used as the lithium vanadium compound.
実施例２４および実施例２５と、比較例５の結果から、従来の正極活物質に加えてリチウムバナジウム化合物を用いた場合、３００サイクル後容量維持率の改善効果が得られることが確認された。
From the results of Example 24 and Example 25 and Comparative Example 5, it was confirmed that when the lithium vanadium compound is used in addition to the conventional positive electrode active material, the improvement effect of the capacity retention rate after 300 cycles can be obtained.
比較例６、７の結果から、カルボン酸エステルを用いた場合においても、リチウムバナジウム化合物を用いない場合、３００サイクル後容量維持率の改善効果が得られないことが確認された。
From the results of Comparative Examples 6 and 7, it was confirmed that the improvement effect of the capacity retention rate after 300 cycles was not obtained even when the carboxylic acid ester was used, when the lithium vanadium compound was not used.
上記結果から、カルボン酸エステルとリチウムバナジウム化合物とを組み合わせた場合において、３００サイクル後容量維持率の改善効果が得られることが確認された。
From the above results, it was confirmed that when the carboxylic acid ester and the lithium vanadium compound were combined, the improvement effect of the capacity retention rate after 300 cycles was obtained.
本発明により、サイクル特性を改善することが可能なリチウムイオン二次電池が提供される。
According to the present invention, a lithium ion secondary battery capable of improving cycle characteristics is provided.
１０…正極、１２…正極集電体、１４…正極活物質層、１８…セパレータ、２０…負極、２２…負極集電体、２４…負極活物質層、３０…積層体、５０…ケース、６０，６２…リード、１００…リチウムイオン二次電池。
DESCRIPTION OF SYMBOLS 10 ... Positive electrode, 12 ... Positive electrode collector, 14 ... Positive electrode active material layer, 18 ... Separator, 20 ... Negative electrode, 22 ... Negative electrode collector, 24 ... Negative electrode active material layer, 30 ... Laminate, 50 ... Case, 60 , 62 ... lead, 100 ... lithium ion secondary battery.
Claims (5)
- 正極と、負極と、前記正極と前記負極の間に位置するセパレータと、電解液とを備えるリチウムイオン二次電池であって、
前記正極がリチウムバナジウム化合物を含み、
前記電解液がカルボン酸エステルを含むことを特徴とするリチウムイオン二次電池。 A lithium ion secondary battery comprising a positive electrode, a negative electrode, a separator positioned between the positive electrode and the negative electrode, and an electrolytic solution,
The positive electrode contains a lithium vanadium compound,
The lithium ion secondary battery, wherein the electrolytic solution contains a carboxylic acid ester. - 前記カルボン酸エステルが、下記化学式（１）で表されることを特徴とする請求項１に記載のリチウムイオン二次電池。
（ここで、Ｒ１およびＲ２は炭素数１～４の直鎖状または分岐状のアルキル基または置換アルキル基であり、Ｒ１とＲ２の炭素数の合計が５以下である。）
(Here, R 1 and R 2 each represent a linear or branched alkyl group having 1 to 4 carbon atoms or a substituted alkyl group, and the total number of carbon atoms of R 1 and R 2 is 5 or less.)
- 前記カルボン酸エステルが、プロピオン酸エステルまたは酢酸エステルであることを特徴とする請求項１または２に記載のリチウムイオン二次電池。 The lithium ion secondary battery according to claim 1, wherein the carboxylic acid ester is propionic acid ester or acetic acid ester.
- 前記カルボン酸エステルが、前記電解液中に５０体積％以上９０体積％以下含まれることを特徴とする請求項１乃至３のいずれか一項に記載のリチウムイオン二次電池。 The lithium ion secondary battery according to any one of claims 1 to 3, wherein the carboxylic acid ester is contained in the electrolytic solution at 50% by volume or more and 90% by volume or less.
- 前記リチウムバナジウム化合物がＬｉＶＯＰＯ４であることを特徴とする請求項１乃至４のいずれか一項に記載のリチウムイオン二次電池。 The lithium ion secondary battery according to any one of claims 1 to 4 , wherein the lithium vanadium compound is LiVOPO4.
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| JPH05234621A (en) * | 1992-02-25 | 1993-09-10 | Matsushita Electric Ind Co Ltd | Nonaqueous electrolyte secondary battery and its manufacture |
| JPH11144757A (en) * | 1992-04-09 | 1999-05-28 | Bridgestone Corp | Nonaqueous electrolyte battery |
| JPH07235295A (en) * | 1994-02-21 | 1995-09-05 | Fuji Photo Film Co Ltd | Nonaqueous secondary battery |
| JP2008140760A (en) * | 2006-06-14 | 2008-06-19 | Sanyo Electric Co Ltd | Nonaqueous electrolytic solution for secondary battery, and nonaqueous electrolytic solution secondary battery using the same |
| WO2012133027A1 (en) * | 2011-03-31 | 2012-10-04 | 三洋電機株式会社 | Non-aqueous electrolyte secondary battery system |
| JP2016085837A (en) * | 2014-10-24 | 2016-05-19 | Tdk株式会社 | Lithium ion secondary battery |
| JP2017082303A (en) * | 2015-10-29 | 2017-05-18 | Tdk株式会社 | Stabilized lithium powder, negative electrode using the same, and lithium ion secondary battery |
| JP2017152126A (en) * | 2016-02-23 | 2017-08-31 | Tdk株式会社 | Negative electrode active material, negative electrode containing negative electrode active material, and lithium ion secondary battery |
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