TW202103359A - Composite material for negative electrode of lithium ion battery and manufacturing method thereof capable of combining graphene, silicon, amorphous carbon and linearly conductive carbon to fabricate negative electrode sheet of high-quality lithium battery - Google Patents
Composite material for negative electrode of lithium ion battery and manufacturing method thereof capable of combining graphene, silicon, amorphous carbon and linearly conductive carbon to fabricate negative electrode sheet of high-quality lithium battery Download PDFInfo
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本發明係為一種用於電池負極的複合材料及其製作方法，特別是關於以碳層包覆複合材料層且以碳材為核心之鋰離子電池負極的複合材料及其製作方法。 The invention relates to a composite material for battery negative electrodes and a manufacturing method thereof, and particularly relates to a composite material for lithium ion battery negative electrodes with a carbon layer covering a composite material layer and a carbon material as the core and a manufacturing method thereof.
現代科技與生活品質的快速發展，各類3C高科技電子產品無不趨向輕、薄、短、小與多功能發展，而電池在使用安全、低成本、品質高及兼具環保等要求下，高性能之鋰電池應運而生，其中，鋰離子二次電池負極材料，可使用介相碳微球、天然石墨、人造石墨等材料來製作。 With the rapid development of modern technology and quality of life, all kinds of 3C high-tech electronic products tend to be light, thin, short, small and multi-functional, and batteries are required to be safe, low-cost, high-quality, and environmentally friendly. High-performance lithium batteries came into being. Among them, lithium ion secondary battery anode materials can be made of mesophase carbon microspheres, natural graphite, artificial graphite and other materials.
目前電池負極活性物質、導電性充填劑以介相碳微球為碳材料之應用越來越多，該碳材料之充放電容量、循環特性及熱安定性較優異，尤其是用為鋰充電電池在作為攜帶型機器末端之電源、超級電容及太陽能電池。 At present, there are more and more applications of using mesophase carbon microspheres as carbon materials for negative electrode active materials and conductive fillers in batteries. The carbon materials have excellent charge and discharge capacity, cycle characteristics and thermal stability, especially for lithium rechargeable batteries. Used as the power source, super capacitor and solar cell at the end of portable machines.
鋰離子電池中負極材料多以石墨為主體，具有電極壽命長、電壓穩定、充放電快速等特性，但由於碳元素理論電容量較低，使得鋰離子電池能量密度之提升受到限制， 現今研究亟需尋找一替代材料以增加電池電容量，矽元素作為鋰離子電池負極材料時，高於石墨類碳材的理論電容量，添加少許劑量矽與碳材混合時可大幅提升負極之單位電容量，未來可應用於下一世代的鋰電池系統中，其中矽/碳材料最早是將SiH4利用CVD方式，使奈米矽均勻沉積於多孔洞碳材上，電容量可從330-360mAh/g提升為1000-2000mAh/g左右，此研究證實矽/碳材料在負極中的實用性。 The anode material in lithium ion batteries is mostly graphite, which has the characteristics of long electrode life, stable voltage, and fast charge and discharge. However, due to the low theoretical capacity of carbon element, the improvement of the energy density of lithium ion batteries is limited. Current research is urgent It is necessary to find an alternative material to increase the battery capacity. When silicon is used as the negative electrode material of lithium-ion batteries, it is higher than the theoretical capacity of graphite-like carbon materials. Adding a small amount of silicon and carbon materials can greatly increase the unit capacity of the negative electrode. In the future, it can be applied to the next generation of lithium battery systems. Among them, the silicon/carbon material is the first to use SiH 4 using CVD to make nanosilicon uniformly deposited on the porous carbon material, and the capacity can be increased from 330-360mAh/g It is about 1000-2000mAh/g. This study confirms the practicability of silicon/carbon materials in the negative electrode.
但由於Si於充放電過程中產生之體積膨脹達4倍之多，使得矽表面會產生不可逆之缺陷，導致電池電容量下降、庫倫效率低等缺點，因此目前業界極需發展出一種矽氧化物或矽碳負極材料，藉由氧化物或碳層來抑制矽在充放電過程中產生的體積膨脹，如此一來，方能同時兼具成本與效能，製作出高品質鋰電池之負極極片。 However, the volumetric expansion of Si during charging and discharging is as much as 4 times, causing irreversible defects on the surface of the silicon, resulting in a decrease in battery capacity and low coulombic efficiency. Therefore, there is a great need for the industry to develop a silicon oxide. Or silicon-carbon anode material, which uses oxide or carbon layer to suppress the volume expansion of silicon during charging and discharging. In this way, both cost and efficiency can be produced to produce high-quality lithium battery negative pole pieces.
鑒於上述習知技術之缺點，本發明之主要目的在於提供一種碳層包覆具複數孔洞之複合材料層且以碳材為核心用於鋰離子電池負極的複合材料，整合石墨烯、矽、非晶相碳、線性導電碳等，以製作出高品質鋰電池之負極極片。 In view of the shortcomings of the above-mentioned conventional technology, the main purpose of the present invention is to provide a composite material with a carbon layer covering a composite material layer with a plurality of pores and using a carbon material as the core for the negative electrode of a lithium ion battery, integrating graphene, silicon, and non- Crystal phase carbon, linear conductive carbon, etc., to produce high-quality lithium battery negative pole pieces.
為了達到上述目的，根據本發明所提出之一方案，一種用於鋰離子電池負極的複合材料，其組合為一種核殼式結構，包括：一核心，該核心係包括一碳材；一複合材料 層，該複合材料層中具有複數個孔洞並包覆該核心，其中該複合材料層包括：矽氧化物、矽元素及石墨烯，其中該石墨烯表面經由化學鍵結而包覆該矽元素；以及一外殼，該外殼包覆該複合材料層以及該核心以形成該核殻式結構，其中該外殼係包括一非晶相碳及一線狀導電碳。 In order to achieve the above objective, according to a solution proposed by the present invention, a composite material for the negative electrode of a lithium ion battery, which is combined into a core-shell structure, includes: a core, the core system includes a carbon material; a composite material Layer, the composite material layer has a plurality of holes and covers the core, wherein the composite material layer includes silicon oxide, silicon element and graphene, wherein the surface of the graphene is chemically bonded to coat the silicon element; and A shell covering the composite material layer and the core to form the core-shell structure, wherein the shell includes an amorphous phase carbon and a linear conductive carbon.
上述的矽之粒徑係為10~800nm之間；該石墨烯係選自單層、多層、還原氧化石墨烯或氧化石墨烯其中之一；該碳材係選自天然石墨、人工石墨、硬碳、軟碳、奈米碳管或石墨烯其中之一或其組合；該複合材料層中之該矽氧化物係為氧化亞矽，氧化亞矽為原料矽經由鹼蝕刻後於熱處理下生成之；該碳層之非晶相碳則可由一有機裂解碳前驅物經鍛燒製程而獲得，該有機裂解碳前驅物可選自葡萄糖、蔗糖、檸檬酸、聚乙烯醇、聚乙二醇、聚丙烯腈、瀝青、酚醛樹脂、聚苯胺、環氧樹脂、聚乙烯吡咯烷酮和不飽合烴氣體其中之一或其混合；該複數線狀導電碳之長徑係大於該複數非晶相碳，其中該複數線狀導電碳係選自碳黑、奈米碳管、碳纖維、石墨烯、石墨片其中之一或其組合；而本發明用於鋰離子電池負極的複合材料，尚需進行一鍛燒製程方能獲得，該鍛燒製程後進行過篩並再以去離子水沖洗，即可獲得本發明具有複數緩衝孔洞的碳層包覆矽氧化物與石墨烯包覆矽並以碳材為核心之用於鋰電池負極材料之複合材料，其中該複合材料比表面積係為1~10m2/g之間。 The particle size of the aforementioned silicon is between 10 and 800 nm; the graphene is selected from one of single-layer, multi-layer, reduced graphene oxide or graphene oxide; the carbon material is selected from natural graphite, artificial graphite, hard One or a combination of carbon, soft carbon, carbon nanotubes or graphene; the silicon oxide in the composite material layer is silousous oxide, which is the raw material silicon produced by alkali etching after heat treatment ; The amorphous carbon of the carbon layer can be obtained from an organic cracked carbon precursor through a calcining process, the organic cracked carbon precursor can be selected from glucose, sucrose, citric acid, polyvinyl alcohol, polyethylene glycol, poly One of acrylonitrile, pitch, phenolic resin, polyaniline, epoxy resin, polyvinylpyrrolidone and unsaturated hydrocarbon gas or a mixture thereof; the long axis of the plurality of linear conductive carbons is larger than the plurality of amorphous carbons, wherein The plurality of linear conductive carbons are selected from one or a combination of carbon black, carbon nanotubes, carbon fibers, graphene, and graphite flakes; and the composite material of the present invention for the negative electrode of a lithium ion battery needs to be calcined The process can only be obtained. After the calcining process, it is screened and then rinsed with deionized water to obtain the carbon-coated silicon oxide and graphene-coated silicon with multiple buffer holes of the present invention, and the carbon material is the core. The composite material used for the negative electrode material of lithium battery, wherein the specific surface area of the composite material is between 1~10m 2 /g.
為了達到上述目的，根據本發明所提出之另一方案，提供一種用於鋰離子電池負極的複合材料之製作方法，步驟包括：(A)提供一蝕刻液、一含矽啟始物進行一第一混合製程後獲得一混合液，該混合液再加入一中止劑，使該混合液成為中性液體；(B)將一有機酸加入步驟(A)之該第一混合液後，再加入一石墨烯並進行混合，以獲得一第二混合液，其中該第二混合液中該石墨烯表面經由化學鍵結而包覆矽；(C)將一增稠劑加入步驟(B)之該第二混合液製作成黏稠之一漿料；(D)將一碳材及一線狀導電碳加入步驟(C)之該漿料中，進行一第二混合製程使該漿料均勻包覆於該碳材之表面；(E)將包覆該漿料之該碳材加入一有機裂解碳層前驅物進行一造粒製程，以獲得一粉體，較低碳化溫度之有機裂解碳前驅物會先形成一外殼於該粉體表面，其中該粉體為包括矽氧化物、石墨烯、矽及碳材之一負極材料前驅物；(F)將步驟(E)之負極材料前驅物進行一鍛燒製程後過篩並以去離子水沖洗，以獲得以一外殼包覆一具有複數孔洞之複合材料層並以一碳材為核心之複合材料。 In order to achieve the above objective, according to another solution proposed by the present invention, a method for manufacturing a composite material for the negative electrode of a lithium ion battery is provided. The steps include: (A) providing an etching solution, a silicon-containing starting material, and performing a first A mixed liquid is obtained after a mixing process, and a terminator is added to the mixed liquid to make the mixed liquid a neutral liquid; (B) an organic acid is added to the first mixed liquid of step (A), and then another Graphene and mixed to obtain a second mixture, wherein the surface of the graphene in the second mixture is chemically bonded to coat silicon; (C) a thickener is added to the second mixture of step (B) The mixed solution is made into a viscous slurry; (D) a carbon material and a linear conductive carbon are added to the slurry in step (C), and a second mixing process is performed so that the slurry is evenly coated on the carbon material (E) Add the carbon material covering the slurry to an organic cracked carbon layer precursor for a granulation process to obtain a powder. The organic cracked carbon precursor with a lower carbonization temperature will first form a The outer shell is on the surface of the powder, wherein the powder is a precursor of a negative electrode material including silicon oxide, graphene, silicon and carbon; (F) after the precursor of the negative electrode material of step (E) is subjected to a calcining process It is sieved and rinsed with deionized water to obtain a composite material with a shell covering a composite material layer with multiple holes and a carbon material as the core.
上述步驟(A)中，該蝕刻液係選自鹼液，例如NaOH、KOH或NH4OH，但不以此為限，濃度係為0.025~2.5M之間，該第一混合製程時間係為1~24小時之間，含矽啟始物則可選自矽粉或矽氧化物粉末，而中止劑則可選自氯化氫(HCl)、硝酸(HNO3)、硫酸(H2SO4)、檸檬酸、醋酸其中之一或 其混合，中止劑的加入的主要目的是要是藉由酸鹼中合使得溶液的PH值達到7，讓溶液內停止蝕刻反應，蝕刻反應所產生之奈米Si、SiO2、SiOx可作為中心核，而[SiO4]4-離子會在步驟(F)中惰性氣氛下的鍛燒製程熱理處下變成矽氧化物(SiOx)。 In the above step (A), the etching solution is selected from alkali solutions, such as NaOH, KOH or NH 4 OH, but not limited to this. The concentration is between 0.025 and 2.5M, and the first mixing process time is Between 1 and 24 hours, the silicon-containing starting material can be selected from silicon powder or silicon oxide powder, and the stopping agent can be selected from hydrogen chloride (HCl), nitric acid (HNO 3 ), sulfuric acid (H 2 SO 4 ), One of citric acid, acetic acid, or a mixture thereof, the main purpose of adding the terminator is to make the pH of the solution reach 7 by neutralizing the acid and alkali, so that the etching reaction in the solution stops, and the nano Si, the nano Si produced by the etching reaction, SiO 2 and SiO x can serve as the central core, and [SiO 4 ] 4- ion will become silicon oxide (SiO x ) under the thermal treatment of the calcining process under an inert atmosphere in step (F).
上述步驟(B)使Si經NaOH處理後之表面Si-OH基與-COOH鍵結，再加入石墨烯，提供足夠之反應時間，使多層石墨烯能藉由表面官能基對Si進行包覆，其中該有機酸係為羧酸(-COOH)之有機酸係選自甲酸、乙酸、丙酸、丁酸、脂肪酸、芳香酸、檸檬酸、乙二酸、順丁烯二酸其中之一或其組合。 In the above step (B), the Si-OH groups on the surface treated with NaOH are bonded with -COOH, and graphene is added to provide sufficient reaction time so that the multi-layer graphene can coat Si with surface functional groups. Wherein the organic acid is a carboxylic acid (-COOH), the organic acid is selected from one of formic acid, acetic acid, propionic acid, butyric acid, fatty acid, aromatic acid, citric acid, oxalic acid, maleic acid or combination.
上述步驟(C)之該增稠劑係為甲基纖維素、羥丙基甲基纖維素、羧甲基纖維素鈉、羥乙基纖維素、海藻酸鈉、甲殼胺、聚丙烯醯胺、聚乙烯醇、聚氧化乙烯、聚丙烯酸、聚丙烯酸鈉、順丁橡膠、丁苯橡膠等其中之一或其組合。 The thickener of the above step (C) is methyl cellulose, hydroxypropyl methyl cellulose, sodium carboxymethyl cellulose, hydroxyethyl cellulose, sodium alginate, chitosan, polyacrylamide, Polyvinyl alcohol, polyethylene oxide, polyacrylic acid, sodium polyacrylate, butadiene rubber, styrene butadiene rubber, etc. or a combination thereof.
上述步驟(D)中更包括加入一碳助導劑，該碳助導劑係選自碳黑、奈米碳管、碳纖維、石墨烯、石墨片其中之一或其組合。 The above step (D) further includes adding a carbon guidance agent, the carbon guidance agent is selected from one of carbon black, carbon nanotubes, carbon fibers, graphene, graphite flakes, or a combination thereof.
上述步驟(D)之該碳材係選自天然石墨、人工石墨、硬碳、軟碳、奈米碳管或石墨烯其中之一或其組合。 The carbon material in the above step (D) is selected from one or a combination of natural graphite, artificial graphite, hard carbon, soft carbon, carbon nanotubes, and graphene.
上述步驟(E)之該造粒製程係選自粉碎、研磨、噴霧乾燥、冷凍乾燥、流體化床、輥壓造粒其中之一或其混合。 The granulation process of the above step (E) is selected from one of pulverization, grinding, spray drying, freeze drying, fluidized bed, roll granulation, or a mixture thereof.
上述步驟(E)之有機裂解碳前驅物係為瀝青或以烴為基礎的材料，其中以烴為基礎的材料係為選自葡萄糖、蔗糖、果糖、以酚為基礎的樹脂、和不飽合烴氣體、乙烯、丙烯、乙炔其中之一或其混合。 The organic pyrolysis carbon precursor in the above step (E) is pitch or hydrocarbon-based material, wherein the hydrocarbon-based material is selected from glucose, sucrose, fructose, phenol-based resin, and unsaturated One of hydrocarbon gas, ethylene, propylene, and acetylene or a mixture thereof.
上述步驟(F)流程中，過篩之篩網網目範圍係為80~600mesh；鍛燒製程之鍛燒溫度範圍係為600℃~900℃之間，最佳溫度範圍為800~900℃之間。 In the above step (F), the mesh range of the screen is 80~600mesh; the calcining temperature range of the calcining process is between 600℃~900℃, and the best temperature range is between 800~900℃ .
本發明可將一黏結劑、一助導劑、及本發明之粉末狀具有複數緩衝孔洞的非晶相碳層包覆氧化亞矽與石墨烯包覆矽並以碳材為核心的複合材料進行混合後，塗布於一金屬薄片上，即可製作出負極極片，當中，黏結劑可以選自聚偏二氟乙烯(Polyvinyldiene Difluoride，PVDF)、羧甲基纖維素(Carboxylmethyl Cellulose，CMC)、丁苯橡膠(Styrene-Butadiene Rubber，SBR)、海藻酸鈉(Alginate)、甲殼素(Chitosan)、聚丙烯酸膠乳(Polyacrylic Latex)其中之一或其混合，助導劑可以選自碳黑、奈米碳管、碳纖維、石墨烯、石墨片其中之一或其混合。 The present invention can mix a binder, a guide agent, and the powdery amorphous carbon layer with multiple buffer holes of the present invention coated with silousite and graphene coated with silicon and a composite material with carbon as the core. Afterwards, it is coated on a metal sheet to produce a negative pole piece. Among them, the binder can be selected from polyvinyldiene difluoride (PVDF), carboxymethyl cellulose (Carboxylmethyl Cellulose, CMC), and styrene-butadiene fluoride (Polyvinyldiene Difluoride, PVDF). Rubber (Styrene-Butadiene Rubber, SBR), sodium alginate (Alginate), chitosan (Chitosan), polyacrylic latex (Polyacrylic Latex) one of or a mixture thereof, the guide agent can be selected from carbon black, carbon nanotubes , Carbon fiber, graphene, graphite flakes or a mixture thereof.
以上之概述與接下來的詳細說明及附圖，皆是為了能進一步說明本創作達到預定目的所採取的方式、手段及功效。而有關本創作的其他目的及優點，將在後續的說明及圖式中加以闡述。 The above summary and the following detailed description and drawings are all for the purpose of further explaining the methods, means and effects adopted by this creation to achieve the intended purpose. The other purposes and advantages of this creation will be explained in the subsequent description and diagrams.
1‧‧‧複合材料 1‧‧‧Composite materials
2‧‧‧核心 2‧‧‧Core
4‧‧‧複合材料層 4‧‧‧Composite material layer
41‧‧‧孔洞 41‧‧‧Hole
6‧‧‧外殼 6‧‧‧Shell
S201-206‧‧‧步驟 S201-206‧‧‧Step
第一圖係為本發明一種用於鋰離子電池負極的複合材料示意圖；第二圖係為本發明一種用於鋰離子電池負極的複合材料製作方法流程圖；第三圖係為本發明Si/SiOx/MLG/C、SiOx(commercial)、Si及SiO2之同步輻射X光繞射(synchrotron X-ray diffraction,SXRD)圖譜；第四圖係為第三圖之局部放大圖；第五圖係為本發明Si/SiOx/MLG/C樣品之SEM圖與(Si,C,O)EDS mapping圖；第六圖係為本發明SiOx(commercial)樣品之SEM圖與(Si,C,O)EDS mapping圖；第七圖係為本發明Si/SiOx/C樣品(實施例2)之SEM圖；第八圖係為本發明Si/SiOx/MLG/C樣品(實施例3)之SEM圖；第九圖係為本發明Si/MLG樣品之SEM圖；第十圖係為本發明Si/SiOx/MLG/C之XPS Si2p之頻譜分析；第十一圖係為本發明SiOx(commercial)之XPS Si2p之頻譜分析；第十二圖係為本發明實施例3 Si/SiOx/MLG/C材料之半電池測試圖；第十三圖係為本發明比較例1 SiOx(commercial)材料之半電池測試；第十四圖係為本發明實施例5 15wt% Si/SiOx/MLG/C+85wt% MCMB材料之半電池測試圖；第十五圖係為本發明15wt% SiOx(commercial)+85wt%
MCMB材料之半電池測試圖；第十六圖係為本發明實施例5(15wt% Si/SiOx/MLG/C+85wt% MCMB)材料與比較例3(15wt% SiOx(commercial)+85wt% MCMB)材料之半電池長循環充放電測試圖；第十七圖係為本發明實施10(SiOxMLG@Si@Gr)SEM影像圖；第十八圖係為本發明實施例11 c-SiOxMLG@Si@Gr之SEM影像圖；第十九圖係為本發明原材料Si粉與實施例11(c-SiOxMLG@Si@Gr)之XRD數據圖；第二十圖係為本發明原料Si粉、實施例10(SiOxMLG@Si@Gr)及實施例11(c-SiOxMLG@Si@Gr)之拉曼光譜分析圖；第二十一圖係為本發明實施例11 c-SiOxMLG@Si@Gr之之XPS Si2p之頻譜分析圖；第二十二圖係為本發明比較例6(Si/SiOx/Gr(commercial))之XPS Si2p之頻譜分析圖；第二十三圖係為本發明比較例4(10wt% SiOx(commercial)+90%wt NG)，實施例6(10wt% Si/SiOx/MLG/C+90%wt MCMB)，實施例7(10wt% Si/SiOxMLG/C+90%wt NG)，實施例12(50wt% c-SiOxMLG@Si@Gr+50wt% NG)之半電池長循環充放電測試圖；第二十四圖係為本發明實施例9(15wt% SiOxMLG@Si+85wt% NG)，實施例10(SiOxMLG@Si@Gr)，實施例11(c-SiOxMLG@Si@Gr)，比較例5(15wt% SiOx(commercial)+85wt% NG)，比較例6(Si/SiOx/Gr(commercial))之半電池長循環充放電測試圖。
The first figure is a schematic diagram of a composite material used in the negative electrode of a lithium ion battery of the present invention; the second figure is a flow chart of a method for manufacturing a composite material used in the negative electrode of a lithium ion battery of the present invention; the third figure is a Si/ The synchrotron X-ray diffraction (SXRD) spectra of SiOx/MLG/C, SiOx (commercial), Si and SiO 2 ; the fourth picture is a partial enlargement of the third picture; the fifth picture is The SEM image and (Si,C,O)EDS mapping of the Si/SiOx/MLG/C sample of the present invention; the sixth image is the SEM image and (Si,C,O)EDS of the SiOx (commercial) sample of the present invention The mapping figure; the seventh figure is the SEM image of the Si/SiOx/C sample (embodiment 2) of the present invention; the eighth figure is the SEM image of the Si/SiOx/MLG/C sample (embodiment 3) of the present invention; Figure 9 is the SEM image of the Si/MLG sample of the present invention; Figure 10 is the spectrum analysis of the XPS Si 2p of Si/SiOx/MLG/C of the present invention; Figure 11 is the XPS of the SiOx (commercial) of the present invention The spectrum analysis of Si 2p ; the twelfth figure is the half-cell test diagram of the Si/SiOx/MLG/C material in the third embodiment of the present invention; the thirteenth figure is the half-cell test of the SiOx (commercial) material in the comparative example 1 of the present invention Test; The fourteenth figure is the half-cell test figure of 15wt% Si/SiOx/MLG/C+85wt% MCMB material in Example 5 of the present invention; the fifteenth figure is the 15wt% SiOx(commercial)+85wt% of the present invention The half-cell test diagram of MCMB material; the sixteenth diagram is the material of Example 5 (15wt% Si/SiOx/MLG/C+85wt% MCMB) and Comparative Example 3 (15wt% SiOx(commercial)+85wt% MCMB) ) The half-cell long-cycle charge and discharge test diagram of the material; the seventeenth diagram is the SEM image of the
以下係藉由特定的具體實例說明本創作之實施方式，熟悉此技藝之人士可由本說明書所揭示之內容輕易地了解本創作之優點及功效。 The following is a specific example to illustrate the implementation of this creation. Those who are familiar with this technique can easily understand the advantages and effects of this creation from the content disclosed in this manual.
矽作為負極材料的理論電容量約3500mAh/g，添加部分劑量可大幅提升電池的負極總體能量密度，但由於Si於充放電過程中產生之體積膨脹達4倍之多，使得矽表面產生不可逆缺陷，導致電池電容量下降、庫倫效率低等缺點；本發明的目的為利用一種包含Si/SiOx/MLG/C結構的來解決上述問題，其最外層的碳層結構係為線型導電碳及利用有機碳源裂解成非晶碳後與SiOx及Si/石墨烯將碳材包覆於其中，形成一種核殼結構，此結構可限制矽在充放電中造成劇烈的體積膨脹，使得矽粉不至產生巨大缺陷而維持其導電通路，並且同時加入一長徑比較長之導電碳，由於其具有較大的長徑比，使活性材在膨脹收縮後其活物顆粒間能此相連，減少負極材料因無法導電或導離子而造成的失效。藉由改變Si上面的氧含量以及石墨烯與碳層之控制，可以將此種SiOx、石墨烯與有機裂解碳碳包覆Si之複合負極材料的電容量控制在與商業化產品相當約1700~1900mAh/g。 The theoretical capacity of silicon as a negative electrode material is about 3500mAh/g. Adding a part of the dose can greatly increase the overall energy density of the battery's negative electrode. However, due to the volume expansion of Si during the charging and discharging process up to 4 times, irreversible defects occur on the surface of the silicon. , Leading to the shortcomings of battery capacity decrease and low Coulomb efficiency; the purpose of the present invention is to use a Si/SiO x /MLG/C structure to solve the above problems, the outermost carbon layer structure is linear conductive carbon and use After the organic carbon source is cracked into amorphous carbon, the carbon material is coated with SiO x and Si/graphene to form a core-shell structure. This structure can limit the violent volume expansion of silicon during charging and discharging, so that the silicon powder is not To produce huge defects to maintain its conductive path, and at the same time add a conductive carbon with a relatively long length and diameter. Because of its large aspect ratio, the active material can be connected between the living particles after expansion and contraction, reducing the negative electrode Material failure caused by inability to conduct electricity or conduct ions. By changing the oxygen content on Si and the control of graphene and carbon layer, the capacitance of the composite anode material of SiOx, graphene and organic cracked carbon carbon coated Si can be controlled to be about 1700~ as commercial products. 1900mAh/g.
請參閱第一圖所示，為本發明一種用於鋰離子電池負極的複合材料示意圖。如圖所示，本發明提供一種用於
鋰離子電池負極的複合材料1，其組合為一種核殼式結構，包括：一核心2，該核心係包括一碳材；一複合材料層4，該複合材料層4有複數個孔洞41並包覆該核心2，其中，該複合材料層4包括：氧化亞矽、矽元素、石墨烯，其中該石墨烯表面經由化學鍵結而包覆該矽元素；一外殼6，該外殼6包覆該複合材料層4以及該核心2，其中該外殼6係包括一非晶相碳及一線狀導電碳。
Please refer to the first figure, which is a schematic diagram of a composite material used in the negative electrode of a lithium ion battery according to the present invention. As shown in the figure, the present invention provides a method for
The
將Si/SiOx/MLG/C複合材料包覆於碳材最外層，可減少在製作該複合材料時之混漿過程中Si,SiOx或MLG較難分散於水中，因其不同材料表面皆具不同性質。若石墨混摻SiOx製備成漿料塗佈於銅箔上之極板，SiOx主要會分散在石墨與石墨間的空隙中，因一般石墨作為負極材料其粒徑約15~30μm，而SiOx商業品目前粒徑約為4~8μm；而把Si/SiOx/C/MLG包覆於石墨表面之極板時，由於本身SiOx材料已經分散於石墨上，因此相較於混摻其分散性較好，並且當SiOx進行充放電後，其體積開始膨脹，會藉由全部的石墨來作為一緩衝。若是採用混摻之目前商業方法，其體積膨脹會有不均勻的情形，進而導致極板上活性材料較容易脫離剝落使電極材料壽命減短。 Coating the Si/SiOx/MLG/C composite material on the outermost layer of the carbon material can reduce the difficulty of dispersing Si, SiOx or MLG in the water during the mixing process when the composite material is made, because different materials have different surfaces nature. If graphite is mixed with SiOx to prepare a slurry coated on copper foil, the SiOx will mainly be dispersed in the gap between graphite and graphite. Generally, graphite is used as a negative electrode material with a particle size of about 15~30μm, while SiOx commercial products The current particle size is about 4~8μm; when Si/SiOx/C/MLG is coated on the electrode plate on the graphite surface, since the SiOx material itself is already dispersed on the graphite, it has better dispersibility than mixing. And when SiOx is charged and discharged, its volume begins to expand, and all the graphite is used as a buffer. If the current commercial method of mixing is used, the volume expansion will be uneven, which will cause the active material on the electrode plate to easily peel off and shorten the life of the electrode material.
請參閱第二圖所示，為本發明一種用於鋰離子電池負極的複合材料之製作方法流程圖。如圖所示，提供一種用於鋰離子電池負極的複合材料之製作方法，步驟包括：(A) 提供一蝕刻液、一含矽啟始物進行一第一混合製程後獲得一混合液，該混合液再加入一中止劑，使該混合液成為中性液體S201；(B)將一有機酸加入步驟(A)之該第一混合液後，再加入一石墨烯並進行混合，以獲得一第二混合液，其中該第二混合液中該石墨烯表面經由化學鍵結而包覆矽S202；(C)將一增稠劑加入步驟(B)之該第二混合液製作成黏稠之一漿料S203；(D)將一碳材及一線狀導電碳加入步驟(C)之該漿料中，進行一第二混合製程使該漿料均勻包覆於該碳材之表面S204；(E)將包覆該漿料之該碳材加入一有機裂解碳層前驅物進行一造粒製程，以獲得一粉體，較低碳化溫度之有機裂解碳前驅物會先形成一外殼於該粉體表面，其中該粉體為包括矽氧化物、石墨烯、矽及碳材之一負極材料前驅物S205；(F)將步驟(E)之負極材料前驅物進行一鍛燒製程後過篩並以去離子水沖洗，以獲得以一外殼包覆一具有複數孔洞之複合材料層並以一碳材為核心之複合材料S206。 Please refer to the second figure, which is a flow chart of a method for manufacturing a composite material for the negative electrode of a lithium ion battery according to the present invention. As shown in the figure, a method for manufacturing a composite material for the negative electrode of a lithium ion battery is provided. The steps include: (A) Provide an etching solution, a silicon-containing starting material and perform a first mixing process to obtain a mixed solution, and then add a stopper to the mixed solution to make the mixed solution a neutral liquid S201; (B) add an organic acid After the first mixed solution of step (A), a graphene is added and mixed to obtain a second mixed solution, wherein the surface of the graphene in the second mixed solution is chemically bonded to coat silicon S202; C) adding a thickener to the second mixed liquid of step (B) to make a viscous slurry S203; (D) adding a carbon material and a linear conductive carbon to the slurry of step (C), A second mixing process is performed to uniformly coat the slurry on the surface of the carbon material S204; (E) The carbon material coating the slurry is added to an organic cracked carbon layer precursor for a granulation process to obtain A powder, the organic cracked carbon precursor with a lower carbonization temperature will first form a shell on the surface of the powder, wherein the powder is a negative electrode material precursor S205 including silicon oxide, graphene, silicon and carbon materials; (F) The negative electrode material precursor of step (E) is subjected to a calcining process, then sieved and rinsed with deionized water to obtain a composite material layer with a plurality of holes covered by a shell and a carbon material as the core The composite material S206.
本發明之Si/SiOx/多層石墨烯(MLG)/非晶碳(C)負極材料與黏結劑、導電助劑依一定比例混成漿料後，將其塗佈於銅箔上，先於80℃下將溶劑烘乾，而後進真空烘箱以110℃烘烤24小時，去除溶劑，完成之極板，以直徑12mm之圓(12Φ)切下，製作成CR2032鈕扣型鋰離子二次電池，並進行半電池(對極為鋰金屬(直徑15mm之圓，15Φ))之電容量試驗，電解液使用1.0M LiPF6在EC(ethylene carbonate)：
FEC(floroethylene carbonate)：DMC(dimethyl carbonate)：EMC(ethylene methyl carbonate)=28：7：10：55溶劑中並額外添加添加劑1% VC(vinylene carbonate)與1.5% PS(1,3-propane sultone)，前述中之黏結劑種類係為PVDF、CMC、SBR、Alginate、Chitosan、LA132之一或其群組，使用的電容量測定機台廠牌型號為BAT-750B。
The Si/SiOx/multilayer graphene (MLG)/amorphous carbon (C) negative electrode material of the present invention is mixed with a binder and a conductive assistant in a certain proportion to form a slurry, and then it is coated on the copper foil, first at 80°C Dry the solvent in the next step, then put it in a vacuum oven at 110°C for 24 hours, remove the solvent, and cut the finished plate into a circle (12Φ) with a diameter of 12mm to make a CR2032 button-type lithium ion secondary battery. Half-cell (for lithium metal (15mm diameter circle, 15Φ)) capacitance test, the electrolyte uses 1.0M LiPF6 in EC (ethylene carbonate):
FEC (floroethylene carbonate): DMC (dimethyl carbonate): EMC (ethylene methyl carbonate) = 28: 7: 10: 55 in the solvent with
實施例1：配製0.25mM NaOH溶液500mL，並持續以200rpm之速度進行攪拌，將25g大小為200nm之矽粉加入上述NaOH溶液中，反應時間為0.5小時，而後加入檸檬酸攪拌作為中止劑，使NaOH與Si停止反應。高溫熱理處900oC進行碳化處理，所得矽負極材料予以粉碎、研磨與過篩後，依比例活性材：導電助劑：PAA：SBR：CMC為73：12：2.5：5.6：6.9進行混漿，過程中CMC會與PAA先進行混合，而後將活性材與導電助劑先以乾混方式混合後再加入CMC與PAA之溶液，最後則將SBR加入混勻，將漿料利用刮刀塗佈方式塗於銅箔上，此樣品稱為Si/SiOx/C-0.5h。 Example 1: Prepare 500 mL of 0.25 mM NaOH solution and continue to stir at 200 rpm. Add 25 g of 200 nm silica powder to the NaOH solution for a reaction time of 0.5 hours, and then add citric acid and stir as a terminating agent. NaOH and Si stop the reaction. Carburizing treatment at 900oC in high temperature heat treatment, after crushing, grinding and sieving the obtained silicon anode material, the active material: conductive additive: PAA: SBR: CMC is 73: 12: 2.5: 5.6: 6.9 for mixing. , During the process, CMC and PAA will be mixed first, then the active material and the conductive additive will be mixed in a dry blend and then the solution of CMC and PAA will be added. Finally, the SBR will be added and mixed, and the slurry will be coated with a doctor blade. Coated on copper foil, this sample is called Si/SiOx/C-0.5h.
實施例2：配製0.25mM NaOH溶液500mL，並持續以200rpm之速度進行攪拌，將25g且其顆粒為200nm之矽粉加入上述NaOH溶液中，反應時間為4小時，而後加入檸檬酸攪拌作為中止劑，使NaOH與Si停止反應。高溫鍛燒900oC進行碳化處理，所得矽負極材料予以粉碎、研磨與過篩後，依實施例1之比例進行混漿及製作極板，此樣品稱為 Si/SiOx/C。 Example 2: Prepare 500 mL of 0.25 mM NaOH solution, and continue to stir at 200 rpm, add 25 g of silica powder with particles of 200 nm to the NaOH solution, the reaction time is 4 hours, and then add citric acid and stir as a terminator , To stop the reaction between NaOH and Si. High temperature calcining at 900oC for carbonization. After crushing, grinding and sieving the resulting silicon anode material, the slurry is mixed and the electrode plate is made according to the ratio of Example 1. This sample is called Si/SiOx/C.
實施例3：配製0.25mM NaOH溶液500mL，並持續以200rpm之速度進行攪拌，將25g且其大小為200nm之矽粉加入上述NaOH溶液中，反應時間為4小時，而後加入檸檬酸攪拌作為中止劑，使NaOH與Si停止反應。而後加入2.5g多層石墨烯(muti-layer graphene,MLG)持續攪拌12h，使奈米矽粉能有效分散於MLG上。高溫鍛燒900oC進行碳化處理，所得矽負極材料予以粉碎、研磨與過篩後，依實施例1之比例進行混漿及製作極板，此樣品稱為Si/SiOx/MLG/C。 Example 3: Prepare 500 mL of 0.25 mM NaOH solution and continue to stir at 200 rpm. Add 25 g of 200nm silica powder to the NaOH solution. The reaction time is 4 hours. Then, citric acid is added and stirred as a terminator. , To stop the reaction between NaOH and Si. Then add 2.5g of muti-layer graphene (MLG) and continue to stir for 12 hours, so that the nanosilica powder can be effectively dispersed on the MLG. High-temperature calcining at 900°C for carbonization, the resulting silicon anode material is crushed, ground and sieved, and then mixed and made into plates according to the ratio of Example 1. This sample is called Si/SiOx/MLG/C.
實施例4：以實施例3的Si/SiOx/MLG/C負極材料(5%)混合95%的商業化石墨材料中間相碳微球，進行混漿(活性材：導電助劑：PAA：SBR：CMC=93：3：0.67：1.5：1.83)、極板製作及電池組裝，此樣品稱為5wt% Si/SiOx/MLG/C+95wt%介相碳微球(mesocarbon microbead,MCMB)。 Example 4: The Si/SiOx/MLG/C negative electrode material (5%) of Example 3 was mixed with 95% of the mesophase carbon microspheres of commercial graphite material for mixing (active material: conductive aid: PAA: SBR) : CMC=93:3:0.67:1.5:1.83), plate production and battery assembly, this sample is called 5wt% Si/SiOx/MLG/C+95wt% mesocarbon microbead (MCMB).
實施例5：以實施例3的Si/SiOx/MLG/C負極材料(15%)混合85%的商業化石墨材料介相碳微球進行混漿(比例與實施例4相同)、極板製作及電池組裝，此樣品稱為15wt% Si/SiOx/MLG/C+85wt% MCMB。 Example 5: The Si/SiO x /MLG/C negative electrode material (15%) of Example 3 was mixed with 85% of the commercial graphite material interphase carbon microspheres for mixing (the ratio is the same as that of Example 4), and the electrode plate Production and battery assembly, this sample is called 15wt% Si/SiO x /MLG/C+85wt% MCMB.
實施例6：以實施例3的Si/SiOx/MLG/C負極材料(15%)混合85%的商業化石墨材料中間相碳微球，進行混漿(比例與實施例4相同)、極板製作及電池組裝，此樣品稱為10wt% Si/SiOx/MLG/C+90wt% MCMB。 Example 6: Use the Si/SiOx/MLG/C negative electrode material (15%) of Example 3 to mix 85% of the commercial graphite material mesophase carbon microspheres, and mix the slurry (the ratio is the same as that of Example 4), and the electrode plate Production and battery assembly, this sample is called 10wt% Si/SiOx/MLG/C+90wt% MCMB.
實施例7：以實施例3的Si/SiOx/MLG/C負極材料(10%)混合90%的商業化天然石墨(NG)負極材料進行混漿(比例與實施例4相同)、極板製作及電池組裝，此樣品稱為10wt% Si/SiOx/MLG/C+90wt% NG。 Example 7: The Si/SiOx/MLG/C anode material (10%) of Example 3 was mixed with 90% commercial natural graphite (NG) anode material for mixing (the ratio is the same as that of Example 4), and the electrode plate was made And battery assembly, this sample is called 10wt% Si/SiOx/MLG/C+90wt% NG.
實施例8：配製0.25mM NaOH溶液300mL，並持續以200rpm之速度進行攪拌，將25g且其大小為700nm之矽粉加入上述NaOH溶液中，並放入具有氧化鋯珠之球磨罐中，研磨時間為4小時。而後加入檸檬酸球磨作為中止劑，使NaOH與Si停止反應。之後再加入2.5g MLG持續攪拌12小時，使MLG能包覆於Si上。所得SiOxMLG負極材料前驅物予以粉碎、研磨與過篩後，高溫熱理處900oC進行碳化處理得到最後產品。依實施例1之漿料比例進行混漿及製作極板，此樣品稱為Si@SiOxMLG。 Example 8: Prepare 300 mL of 0.25 mM NaOH solution and continue to stir at 200 rpm. Add 25 g of silicon powder with a size of 700 nm to the above NaOH solution and put it in a ball mill tank with zirconia beads. Grinding time For 4 hours. Then a citric acid ball mill was added as a terminator to stop the reaction of NaOH and Si. Then add 2.5g MLG and continue stirring for 12 hours to enable MLG to coat Si. After the obtained precursor of SiOxMLG negative electrode material is crushed, ground and sieved, the final product is obtained by carbonization treatment at 900°C in a high-temperature heat treatment section. The slurry was mixed and the plates were made according to the slurry ratio of Example 1. This sample is called Si@SiOxMLG.
實施例9：以實施例8的SiOxMLG負極材料(15%)混合85%的商業化天然石墨負極材料進行混漿(比例與實施例4相同)、極板製作及電池組裝，此樣品稱為15wt% Si@SiOxMLG+85wt% NG。 Example 9: The SiOxMLG anode material (15%) of Example 8 was mixed with 85% of the commercial natural graphite anode material for slurry mixing (the ratio is the same as that of Example 4), plate production and battery assembly. This sample is called 15wt % Si@SiOxMLG+85wt% NG.
實施例10：配製0.25mM NaOH溶液300mL，並持續以200rpm之速度進行攪拌，將25g且其大小為700nm之矽粉加入上述NaOH溶液中，並放入具有氧化鋯珠之球磨罐中，研磨時間為4小時。而後加入檸檬酸球磨作為中止劑，使NaOH與Si停止反應。之後再加入2.5g MLG持續攪拌12 小時，使MLG能包覆於Si上。之後再加入天然石墨與線狀導電助劑混入漿料中，攪拌12小時後產生一均勻SiOxMLG包覆石墨之漿料，將漿料刮塗於玻璃上進行110oC烘乾得到前驅物。所得SiOxMLG負極材料前驅物予以粉碎、研磨與過篩後，高溫熱理處900oC進行碳化處理得到最後產品。依實施例4之漿料比例進行混漿及製作極板，此樣品稱為SiOxMLG@Si@Gr。 Example 10: Prepare 300 mL of 0.25 mM NaOH solution and continue to stir at 200 rpm. Add 25 g of silicon powder with a size of 700 nm to the NaOH solution and put it in a ball mill tank with zirconia beads. Grinding time For 4 hours. Then a citric acid ball mill was added as a terminator to stop the reaction of NaOH and Si. Then add 2.5g MLG and continue stirring 12 Hours, so that MLG can be coated on Si. Afterwards, natural graphite and linear conductive additives are added and mixed into the slurry. After stirring for 12 hours, a uniform SiOxMLG-coated graphite slurry is produced. The slurry is scraped onto the glass and dried at 110°C to obtain the precursor. After the obtained precursor of SiOxMLG negative electrode material is crushed, ground and sieved, the final product is obtained by carbonization treatment at 900°C in a high-temperature heat treatment section. The slurry was mixed and the electrode plate was made according to the slurry ratio of Example 4. This sample is called SiOxMLG@Si@Gr.
實施例11：配製0.25mM NaOH溶液300mL，並持續以200rpm之速度進行攪拌，將25g且其大小為700nm之矽粉加入上述NaOH溶液中，並放入具有氧化鋯珠之球磨罐中，研磨時間為4小時。而後加入檸檬酸球磨作為中止劑，使NaOH與Si停止反應。之後再加入2.5g MLG持續攪拌12小時，使MLG能包覆於Si上。之後再加入葡萄糖作為碳源、線狀導電助劑以及天然石墨混入漿料中，並以CMC調整黏稠度，攪拌12小時後產生一均勻SiOxMLG包覆石墨之漿料，將漿料刮塗於玻璃上進行110oC烘乾得到前驅物。所得SiOxMLG負極材料前驅物予以粉碎、研磨與過篩後，高溫熱理處900oC進行碳化處理得到最後產品(550mAh/g樣品)。依實施例4之漿料比例進行混漿及製作極板，此樣品稱為c-SiOxMLG@Si@Gr。 Example 11: Prepare 300 mL of 0.25 mM NaOH solution and continue to stir at 200 rpm. Add 25 g of silicon powder with a size of 700 nm to the NaOH solution and put it in a ball mill tank with zirconia beads. Grinding time For 4 hours. Then a citric acid ball mill was added as a terminator to stop the reaction of NaOH and Si. Then add 2.5g MLG and continue stirring for 12 hours to enable MLG to coat Si. Then add glucose as a carbon source, linear conductive additives and natural graphite into the slurry, and adjust the viscosity with CMC. After stirring for 12 hours, a uniform SiOxMLG-coated graphite slurry will be produced, and the slurry will be scraped onto the glass. Dry at 110oC to get the precursor. After the obtained SiOxMLG negative electrode material precursor is crushed, ground and sieved, the final product (550mAh/g sample) is obtained by carbonization treatment at 900°C in a high-temperature heat treatment section. The slurry was mixed and the electrode plate was made according to the slurry ratio of Example 4. This sample is called c-SiOxMLG@Si@Gr.
實施例12：以實施例11的c-SiOxMLG@Si@Gr負極材料(50%)混合50%的商業化天然石墨負極材料進行混漿 (比例與實施例4相同)、極板製作及電池組裝(450mAh/g樣品)，此樣品稱為50wt% c-SiOxMLG@Si@Gr+50wt% NG。 Example 12: The c-SiOxMLG@Si@Gr anode material (50%) of Example 11 was mixed with 50% commercial natural graphite anode material for slurry mixing (The ratio is the same as that of Example 4), plate production and battery assembly (450mAh/g sample), this sample is called 50wt% c-SiOxMLG@Si@Gr+50wt% NG.
比較例1：購買商業化之碳包覆SiOx粉體(0.8<x<0.95)，以相同的混漿製程與比例(與實施例1相同)製作極板並組成半電池測試，與實施例3比較，此樣品稱為SiOx(commercial)。 Comparative Example 1: Purchase commercialized carbon-coated SiOx powder (0.8<x<0.95), use the same mixing process and ratio (same as in Example 1) to make plates and form a half-cell test, as in Example 3. For comparison, this sample is called SiOx (commercial).
比較例2：以比較例1的SiOx負極材料混合95%的商業化石墨材料中間相碳微球，進行混漿(比例與實施例4相同)、極板製作及電池組裝(450mAh/g樣品)，此樣品稱為5wt% SiOx(commercial)+95wt% MCMB。 Comparative Example 2: The SiOx negative electrode material of Comparative Example 1 was mixed with 95% of the mesophase carbon microspheres of commercial graphite material, and the slurry was mixed (the ratio is the same as that of Example 4), the electrode plate was made and the battery was assembled (450mAh/g sample) , This sample is called 5wt% SiOx(commercial)+95wt% MCMB.
比較例3：以比較例1的SiOx負極材料混合85%的商業化石墨材料中間相碳微球，進行混漿(比例與實施例4相同)、極板製作及電池組裝(550mAh/g樣品)，此樣品稱為15wt% SiOx(commercial)+85wt% MCMB。 Comparative Example 3: The SiOx negative electrode material of Comparative Example 1 was mixed with 85% of the mesophase carbon microspheres of commercial graphite material, and the slurry was mixed (the ratio is the same as that of Example 4), the electrode plate was made and the battery was assembled (550mAh/g sample) , This sample is called 15wt% SiOx(commercial)+85wt% MCMB.
比較例4：以比較例1的SiOx負極材料混合95%的商業化石墨材料中間相碳微球，進行混漿(比例與實施例4相同)、極板製作及電池組裝(450mAh/g樣品)，此樣品稱為5wt% SiOx(commercial)+95wt% NG。 Comparative Example 4: The SiOx negative electrode material of Comparative Example 1 was mixed with 95% of the mesophase carbon microspheres of commercial graphite material, and the slurry was mixed (the proportion is the same as that of Example 4), the plate production and the battery assembly (450mAh/g sample) , This sample is called 5wt% SiOx (commercial) + 95wt% NG.
比較例5：以比較例1的SiOx負極材料混合85%的商業化石墨材料中間相碳微球，進行混漿(比例與實施例4相同)、極板製作及電池組裝(550mAh/g樣品)，此樣品稱為15wt% SiOx(commercial)+85wt% NG。 Comparative Example 5: The SiOx negative electrode material of Comparative Example 1 was mixed with 85% of the mesophase carbon microspheres of commercial graphite material, and the slurry was mixed (the ratio is the same as that of Example 4), the electrode plate was made and the battery was assembled (550mAh/g sample) , This sample is called 15wt% SiOx(commercial)+85wt% NG.
比較例6：購買商業化之Si/SiOx/石墨混合之負極材料，以相同的混漿製程與比例(與實施例4相同)製作極板並組成半電池測試(550mAh/g樣品)，此樣品稱為Si/SiOx/Gr(commercial)。 Comparative Example 6: Purchasing a commercialized Si/SiOx/graphite mixed negative electrode material, using the same mixing process and ratio (same as Example 4) to make a plate and forming a half-cell test (550mAh/g sample), this sample Called Si/SiOx/Gr (commercial).
請參閱第三圖所示，為本發明Si/SiOx/MLG/C、SiOx(commercial)、Si及SiO2之同步輻射X光繞射(synchrotron X-ray diffraction,SXRD)圖譜、請參閱第四圖所示，為本發明第三圖之局部放大圖。如圖所示，波長為0.826567Å，Si/SiOx/MLG/C與標準品Si在戲的峰值位置與強度上十分接近。差異在於~12o的地方為SiOx的非晶相繞射峰值，由圖4放大圖可以清楚的看到，Si之標準品在此處仍有些許峰值的SiO2，此部分可由SiO2的標準品比對得知。而在Si的標準品上仍可以看到SiO2的訊號是因為Si在大氣下本身就容易氧化而導致形成一SiO2薄層。而在Si/SiOx/MLG/C的樣品中可以看到SiO2之訊號較Si標準品強度高出許多，因此可以確認此合成方式確實可以將Si製作成Si/SiOx之複合樣品，但由於X光對於氧的敏感度較差，因此要判斷其為SiO2或SiOx將需以光電子能譜儀(XPS)來進行判定。在商業化SiOx的部分，是一種非晶相之材料由Si與SiO2組成，目前在此材料之結構研究上認為Si原子周圍能同時與四個Si原子鍵結(Si相)或與四個O原子鍵結(SiO2相)為一種兩相材料，但也有研究指出SiOx是一種單相材料，其中Si-Si鍵及Si-O鍵是隨機分布在整個結 構中的[24~29]。在SXRD之結果，可以得知此材料Si/SiOx/MLG/C確實是有非晶相SiOx與晶相的Si所組成之材料。 Please refer to the third figure, which is the synchrotron X-ray diffraction (SXRD) spectrum of Si/SiOx/MLG/C, SiOx (commercial), Si and SiO 2 of the present invention. Please refer to the fourth The figure shown is a partial enlarged view of the third figure of the present invention. As shown in the figure, the wavelength is 0.826567Å, and the peak position and intensity of Si/SiOx/MLG/C and standard Si are very close. The difference is that ~12o is the amorphous phase diffraction peak of SiOx. It can be clearly seen from the enlarged view of Fig. 4 that there is still some peak SiO2 in the standard product of Si. This part can be compared with the standard product of SiO2. Learned. The SiO2 signal can still be seen on the Si standard product because Si itself is easily oxidized in the atmosphere, resulting in the formation of a thin SiO2 layer. In the Si/SiOx/MLG/C samples, it can be seen that the SiO2 signal is much stronger than the Si standard product. Therefore, it can be confirmed that this synthesis method can indeed produce Si/SiOx composite samples, but due to X-ray The sensitivity to oxygen is poor, so to determine whether it is SiO2 or SiOx will need to be determined by photoelectron spectroscopy (XPS). In the part of commercial SiOx, it is an amorphous phase material composed of Si and SiO2. At present, in the structure research of this material, it is believed that Si atoms can be bonded with four Si atoms at the same time (Si phase) or with four O atoms. Atomic bonding (SiO2 phase) is a two-phase material, but studies have also pointed out that SiOx is a single-phase material, in which Si-Si bonds and Si-O bonds are randomly distributed throughout the structure [24~29]. From the results of SXRD, it can be known that the material Si/SiOx/MLG/C is indeed a material composed of amorphous SiOx and crystalline Si.
請參閱第五圖所示，為本發明Si/SiOx/MLG/C之SEM(scan electron microscope)影像與其EDS mapping圖、請參閱第六圖所示，為本發明SiOx(commercial)樣品之SEM圖與(Si,C,O)EDS mapping圖。如圖所示，第五圖為Si/SiOx/MLG/C之SEM(scan electron microscope)影像與其EDS mapping之結果，包含C,Si,O三個元素，由Si可以看到是均勻分布於顆粒上的，而O與C可以觀察到在顆粒外圍之濃度是較高的，內部核心的部分O與C較少，因此與SXRD之結果可推論，外殼之材料組成主要為C與SiOx而內部核心主要為Si，驗證了本發明所提出之核殼材料之構想，而相較於SiOx(commercial)樣品(第五圖)，其EDS mapping結果顯示C,Si,O是均勻分布在顆粒上面的，並且C的含量之較低的，因此商業化產品是由高溫氣相法製作而成，因此整個塊材的組成是一致的，最後才進行粉碎及進行CVD碳包覆。 Please refer to the fifth figure, which is the SEM (scan electron microscope) image of the Si/SiOx/MLG/C of the present invention and its EDS mapping. Please refer to the sixth figure, which is the SEM image of the SiOx (commercial) sample of the present invention. And (Si,C,O)EDS mapping diagram. As shown in the figure, the fifth image is the result of the SEM (scan electron microscope) image of Si/SiOx/MLG/C and its EDS mapping. It contains three elements of C, Si, and O. It can be seen from Si that they are uniformly distributed in the particles. It can be observed that the concentration of O and C in the periphery of the particle is higher, and the inner core part has less O and C. Therefore, it can be inferred from the result of SXRD that the material composition of the outer shell is mainly C and SiOx while the inner core It is mainly Si, which validates the concept of the core-shell material proposed by the present invention. Compared with the SiOx (commercial) sample (the fifth figure), the EDS mapping results show that C, Si, and O are evenly distributed on the particles. And the content of C is low, so the commercial products are made by high-temperature gas phase method, so the composition of the whole block is the same, and finally it is crushed and coated with CVD carbon.
請參閱第七圖所示，為本發明Si/SiOx/C樣品(實施例2)之SEM圖、請參閱第八圖所示，為本發明Si/SiOx/MLG/C樣品(實施例3)之SEM圖。如圖所示，可以明顯看到在製程中加入MLG作為Si/SiOx之載體後，減少了較細小粉末之生成，因Si會與MLG鍵結而形成一複材。為了證 實MLG在此複合材料中會與Si進行自組裝堆疊，因此另外製作一樣品是不含SiOx(圖九)，由圖九之SEM可以看到石墨烯片確實覆蓋有Si顆粒。由實施例2與實施例3之比較可以看到，雖然MLG之添加使得Si/SiOx/MLG/C複合材料之可逆電容量下降，因本身MLG的電容量較Si/SiOx低，但在首圈之庫倫效率上是有所提升的。主要是因分散性之改善以及對於Si導電性之增加，使得Si/SiOx在充放電過程中較不易破碎或剝離而失去活性，進而提高了庫倫效率。 Please refer to the seventh figure, which is the SEM image of the Si/SiOx/C sample of the present invention (embodiment 2), please refer to the eighth figure, which is the Si/SiOx/MLG/C sample of the present invention (embodiment 3) The SEM image. As shown in the figure, it can be clearly seen that after adding MLG as the carrier of Si/SiOx in the process, the generation of finer powder is reduced, because Si will bond with MLG to form a composite material. To prove The real MLG will self-assemble and stack with Si in this composite material, so another sample is made without SiOx (Figure 9). From the SEM of Figure 9, it can be seen that the graphene sheet is indeed covered with Si particles. From the comparison between Example 2 and Example 3, it can be seen that although the addition of MLG reduces the reversible capacitance of the Si/SiOx/MLG/C composite material, the capacitance of MLG itself is lower than that of Si/SiOx, but in the first lap The efficiency of Coulomb has been improved. Mainly due to the improvement of dispersibility and the increase of conductivity to Si, Si/SiOx is less likely to be broken or peeled off and lose its activity during the charge and discharge process, thereby increasing the Coulomb efficiency.
請參閱第十圖所示，為本發明Si/SiOx/MLG/C之XPS Si2p之頻譜分析、請參閱第十一圖所示，為本發明SiOx(commercial)之XPS Si2p之頻譜分析。如圖所示，Si/SiOx/MLG/C之樣品表面Si的價數由Si0至Si4+都有，由表二的XPS全頻譜掃描之C,O,Si半定量分析結果顯示Si/SiOx/MLG/C樣品的百分比為31%,39%,30%，但SiOx(commercial)樣品的百分比為87%,10%,3%，有較大的差異，主要是因SiOx(commercial)樣品是由SiOx先經高溫氣相法製作而成，而後才進行CVD碳包覆，而XPS分析主要是表面分析(深度~10nm)，因此會使得SiOx(commercial)分析上得到較多的C訊號。在Si/SiOx/MLG/C樣品上，外殼材料組成為SiOx/C，因此得到表面之組成為C,O,Si之含量相近。進一步將Si2p分峰分析價數分布(表三)，由不同Si價數分析計算結果得知，此材料若將其通式平均為SiOx，其x為1.56。但 我們可推估SiOx(x=1.56)的單位克電容量應在800mAh g-1以下，但由表一中可知Si/SiOx/MLG/C樣品之可逆電容量為1814mAh g-1，因此再次證明此材料是由外殼SiOx/C以及內核Si/MLG之複合材料。反觀SiOx(commercial)之樣品，Si之價數主要為2+，經價數分析計算可知x=0.94，此與該廠商之專利所註明的氧含量(x=0.95)相近。 See Figure tenth, spectrum analysis Si / SiOx / MLG / C XPS Si 2p of the present invention, see Figure eleventh, spectrum analysis SiOx (commercial) XPS Si 2p of the present invention. As shown in the figure, the valence of Si on the sample surface of Si/SiOx/MLG/C ranges from Si 0 to Si 4+ . The semi-quantitative analysis results of C, O, and Si of the XPS full spectrum scan in Table 2 show that Si/ The percentages of SiOx/MLG/C samples are 31%, 39%, 30%, but the percentages of SiOx (commercial) samples are 87%, 10%, 3%, there is a big difference, mainly due to SiOx (commercial) samples It is made of SiOx by high-temperature gas phase method, and then CVD carbon coating. XPS analysis is mainly surface analysis (depth ~ 10nm), so more C signals will be obtained in SiOx (commercial) analysis. On the Si/SiOx/MLG/C sample, the shell material composition is SiOx/C, so the surface composition is C, O, and the Si content is similar. Further analyze the valence distribution of Si2p by peak analysis (Table 3). From the analysis and calculation results of different Si valences, it is known that if the general formula of this material is averaged as SiOx, its x is 1.56. However, we can estimate that the capacitance per gram of SiOx (x=1.56) should be below 800mAh g-1, but from Table 1, it can be seen that the reversible capacitance of the Si/SiOx/MLG/C sample is 1814mAh g-1, so again It is proved that this material is a composite material of shell SiOx/C and core Si/MLG. In contrast to the SiOx (commercial) sample, the valence of Si is mainly 2+. The valence analysis and calculation show that x=0.94, which is similar to the oxygen content (x=0.95) specified in the manufacturer’s patent.
請參閱第十二圖所示，為本發明實施例3 Si/SiOx/MLG/C材料之半電池測試圖、請參閱第十三圖所示，為本發明比較例1 SiOx(commercial)材料之半電池測試。如圖所示，第十二圖為Si之0.4V氧化還原特徵平台與SiOx斜直線上升所構成，而圖十三則為SiOx(commercial)之特性充放電曲線，但此兩者材料在單獨使用上有其庫倫效率低以及壽命 不佳的問題，因此在此測試中只測其首圈庫倫效率以及可逆之電容量。兩者之比較可以看到Si/SiOx/MLG/C之樣品具有較高的可逆電容量(1814mAh g-1)，而SiOx(commercial)為一般商業化可達之電容量~1600mAh g-1。而庫倫效率Si/SiOx/MLG/C則稍低~2%，但我們由表一混摻石墨之測試結果可以看到，混摻後兩者樣品之庫倫效率不論在5%或是15%之混摻，首圈庫倫效率皆是相近的。因此我們可以推論，Si/SiOx/MLG/C在單獨使用時，因為沒有其他石墨材能幫助抑制其體積膨脹，使得庫倫效率稍低於SiOx(commercial)，SiOx(commercial)因為在首圈活化後有大量的Li2O與Li4SiO4可以幫助抑制體積膨脹，而使庫倫效率稍高。由此，從表三可知此二者材料首圈庫倫效率較低的問題，其導致之原因是有所不同的。SiOx(commercial)是因首圈需要額外的鋰去形成Li2O與Li4SiO4。Si/SiOx/MLG/C是因核心Si體積膨脹使得碎裂導致首圈庫倫效率較低，當然其外殼SiOx仍會消耗部分的鋰形成Li2O與Li4SiO4幫助抑制體積膨脹。但藉由混摻的石墨共同吸收體積之膨脹後，實施例4、5與比較例2、3的首圈庫倫效率是相近的，並且Si/SiOx/MLG/C因可逆電容量較高，因此在混摻相同比例之石墨後形成之負極材料單位克電容量是較SiOx(commercial)高的。 Please refer to Figure 12, which is a half-cell test diagram of Si/SiOx/MLG/C material in Example 3 of the present invention. Please refer to Figure 13, which is a comparative example 1 of the SiOx (commercial) material of the present invention. Half-cell test. As shown in the figure, the twelfth figure is composed of the 0.4V redox characteristic platform of Si and the sloping linear rise of SiOx, and figure 13 is the characteristic charge-discharge curve of SiOx (commercial), but these two materials are used separately It has its low Coulomb efficiency and longevity Poor problem, so in this test only the first lap Coulomb efficiency and reversible capacitance are measured. The comparison between the two shows that the sample of Si/SiOx/MLG/C has a higher reversible capacitance (1814mAh g-1), while SiOx (commercial) is a generally commercialized capacitance ~1600mAh g-1. The coulombic efficiency of Si/SiOx/MLG/C is slightly lower by ~2%, but we can see from the test results of mixed graphite in Table 1, that the coulombic efficiency of the two samples after mixing is no matter whether it is between 5% or 15%. Mixed, the first lap Coulomb efficiency is similar. Therefore, we can infer that when Si/SiOx/MLG/C is used alone, because there is no other graphite material that can help inhibit its volume expansion, the coulombic efficiency is slightly lower than SiOx (commercial), SiOx (commercial) is because after the first loop activation A large amount of Li2O and Li4SiO4 can help suppress volume expansion and make the Coulomb efficiency slightly higher. Therefore, it can be seen from Table 3 that the first lap Coulomb efficiency of the two materials is relatively low, and the causes are different. SiOx (commercial) is because the first lap requires extra lithium to form Li2O and Li4SiO4. Si/SiOx/MLG/C is due to the volume expansion of the core Si, which causes fragmentation to cause low first-lap coulombic efficiency. Of course, the shell SiOx still consumes part of the lithium to form Li2O and Li4SiO4 to help suppress volume expansion. However, after the mixed graphite absorbs the volume expansion together, the first-lap coulombic efficiency of Examples 4 and 5 and Comparative Examples 2 and 3 are similar, and the reversible capacitance of Si/SiOx/MLG/C is higher, so The capacitance per gram of the negative electrode material formed by mixing the same proportion of graphite is higher than that of SiOx (commercial).
請參閱第十四圖所示，為本發明實施例5 15wt% Si/SiOx/MLG/C+85wt% MCMB材料之半電池測試圖、請參閱第十五圖所示，為本發明15wt% SiOx(commercial)+85wt% MCMB材料之半電池測試圖、請參閱第十六圖所示，為本發明實施例5(15wt% Si/SiOx/MLG/C+85wt% MCMB)材料與比較例3(15wt% SiOx(commercial)+85wt% MCMB)材料之半電池長循環充放電測試圖。如圖所示，可以看到雖然只混摻了15%的Si/SiOx/MLG/C或SiOx(commercial)，但以電容量來看矽所佔之電容量仍較高，因此在充放電曲線上仍是以矽氧基材料為主。但由於有85%的石墨負極，因此可以有較好的首圈庫倫效率以及循環壽命。第十六圖為實施例5 15wt% Si/SiOx/MLG/C+85wt% MCMB材料與比較例3 15wt% SiOx(commercial)+85wt% MCMB材料之半電池長循環充放電測試，電流大小為0.5C(1C=550mA g-1)。實施例5有較佳的穩定性，在0.1C充放電循環5圈並以0.5C速率進行長循環測試100圈後，電容量仍可維持於80%以上。但比較例3在相同的條件測試下，0.5C速率下80圈後電容量有較大之衰退，並且在100圈後電容量僅剩62%。 Please refer to Figure 14, which is a half-cell test diagram of 15wt% Si/SiOx/MLG/C+85wt% MCMB material in Example 5 of the present invention. Please refer to Figure 15, which is 15wt% SiOx of the present invention. (commercial)+85wt% MCMB material half-cell test chart, please refer to Figure 16, which is the embodiment 5 of the present invention (15wt% Si/SiOx/MLG/C+85wt% MCMB) material and comparative example 3 ( 15wt% SiOx(commercial)+85wt% MCMB) half-cell long-cycle charge-discharge test chart. As shown in the figure, it can be seen that although only 15% Si/SiOx/MLG/C or SiOx (commercial) is mixed, the capacitance occupied by silicon is still relatively high in terms of capacitance, so the charge and discharge curve The above is still mainly based on silica-based materials. However, due to the 85% graphite negative electrode, it can have better first-lap Coulomb efficiency and cycle life. The sixteenth figure shows Example 5 15wt% Si/SiOx/MLG/C+85wt% MCMB material and Comparative Example 3 15wt% SiOx (commercial)+85wt% MCMB material half-cell long cycle charge and discharge test, the current size is 0.5 C(1C=550mA g-1). Example 5 has better stability. After a charge-discharge cycle of 0.1C for 5 cycles and a long cycle test at a rate of 0.5C for 100 cycles, the capacitance can still be maintained above 80%. However, in Comparative Example 3, under the same test conditions, the capacitance has a greater decline after 80 cycles at a rate of 0.5C, and only 62% of the capacitance remains after 100 cycles.
請參閱第十七圖所示，為本發明實施10(SiOxMLG@Si@Gr)SEM影像圖、請參閱第十八圖所示，為本發明實施例11 c-SiOxMLG@Si@Gr之SEM影像及圖。如圖所示，第十七圖實施例10(SiOxMLG@Si@Gr)BET比表面積為
10.9m2/g，雖然有優異之電化學特性，但由於其多孔性使比表面積較大，伴隨產生其他缺點(如：混漿不易、庫倫效率、電解液消耗等)。而第十八圖實施例11(c-SiOxMLG@Si@Gr)樣品藉由表面改質，使BET比表面積由原先10.9m2/g下降至5.2m2/g(降低~50%)，由SEM影像亦可觀察到形成較光滑之球體。充放電之首圈庫倫效率及壽命可由表二結果比較之，實施例10其可逆電容量為573mAh/g，首圈庫倫效率為87.7%,在0.5C速率下充放電100圈後電容量可維持於76%。在實施例11之部分，其可逆電容量為570mAh/g，首圈庫倫效率為89.8%，在0.5C速率下充放電100圈後電容量可維持於88.8%。結果顯示此表面改質對於首圈庫倫效率以及壽命皆有顯著提升，其原因即為降低了BET比較面積進而減少Si或SiOx與電解液反應。並且在可逆電容量上僅損失0.5%，可能因表面改質使其電子導電性較佳使得其可逆電容量並沒有明顯的降低，此部分表面結構分析會於後續XPS分析中詳述。
Please refer to Figure 17, which is the SEM image of
請參閱第十九圖所示，為本發明原材料Si粉與實施例11(c-SiOxMLG@Si@Gr)之XRD數據圖，第十九圖中波長為1.54056Å，其中2H為Hexagonal，3R為Rhombohedral兩者不同結構之石墨。2H與3R之差異在石墨層堆疊時之排列，此天然石墨原料經XRD鑑定本身就具有兩者之結構。在觀察Si(111)與Si(200)之部分時，兩者角度較原材料Si粉來的低，即峰值往低角度偏移，晶格常數變大。原因主要是O與Si鍵 結反應生成SiOx之結果。由於XRD僅能分析具結晶相之材料，SiOx還需藉由拉曼光譜與XPS作進一步分析。 Please refer to Figure 19, which is the XRD data diagram of Si powder as the raw material of the present invention and Example 11 (c-SiOxMLG@Si@Gr). In Figure 19, the wavelength is 1.54056 Å, where 2H is Hexagonal and 3R is Rhombohedral graphite with two different structures. The difference between 2H and 3R is the arrangement when the graphite layers are stacked. The natural graphite raw material is identified by XRD as having the structure of both. When observing the parts of Si(111) and Si(200), the angle of the two is lower than that of the raw material Si powder, that is, the peak value shifts to a lower angle, and the lattice constant becomes larger. The main reason is the bond between O and Si The result of the junction reaction forming SiOx. Since XRD can only analyze materials with crystalline phases, SiOx needs to be further analyzed by Raman spectroscopy and XPS.
請參閱第二十圖所示，為本發明原料Si粉、實施例10(SiOxMLG@Si@Gr)及實施例11(c-SiOxMLG@Si@Gr)之拉曼光譜分析圖，如第二十圖所示，由拉曼光譜可確認原材料Si粉為結晶相之Si，而SiOxMLG@Si@Gr與c-SiOxMLG@Si@Gr為結晶相之Si與非晶相Si之混合物，其中非晶相Si即為SiOx。此兩個樣品之差異在c-SiOxMLG@Si@Gr最外層還有非晶相碳層之改質，但由於C含量較高，因此在熱處理時有較多的非晶相Si轉化為晶相Si，所以SiOx之含量較SiOxMLG@Si@Gr來的低。 Please refer to Figure 20, which is the Raman spectrum analysis diagram of the raw material Si powder of the present invention, Example 10 (SiOxMLG@Si@Gr) and Example 11 (c-SiOxMLG@Si@Gr), such as As shown in the figure, it can be confirmed by Raman spectroscopy that the raw material Si powder is crystalline Si, and SiOxMLG@Si@Gr and c-SiOxMLG@Si@Gr are the mixture of crystalline Si and amorphous Si, of which the amorphous phase Si is SiOx. The difference between the two samples is the modification of the amorphous carbon layer in the outermost layer of c-SiOxMLG@Si@Gr. However, due to the higher C content, more amorphous Si is transformed into crystalline phase during heat treatment. Si, so the content of SiOx is lower than that of SiOxMLG@Si@Gr.
請參閱第二十一圖所示，為本發明實施例11(c-SiOxMLG@Si@Gr)之XPS Si2p之頻譜分析圖，請參閱第二十二圖所示，為本發明為比較例6(Si/SiOx/Gr(commercial))之XPS Si2p之頻譜分析圖，價數之分峰Si0為99.6eV,Si+1為100.1eV,Si+2為101.5eV,Si+3為102.9eV,Si+4為103.9eV。由兩者相較商業品之Si/SiOx/Gr材料Si之價數分布由4價到0價都有，與實施例3之結果(圖八)相似，但由於0價Si在表面容易與電解液反應，因此表面存在0價Si會使其電池壽命較差。而實施例11之結果顯示其表面價數之分析結果主要以Si3+存在，並具有少量的2價與4價，此表面組成相較於商業品SiOx或是Si/SiOx/Gr混合材料有所不同。表五為 XPS全頻譜掃描比較例1(SiOx(commercial))，比較例6(Si/SiOx/Gr(commercial))，實施例8(SiOxMLG@Si@Gr)及實施例11(c-SiOxMLG@Si@Gr)之C,O,Si半定量分析。比較例1在先前有提及其為SiOx進行CVD碳包覆，因此在進行XPS表面分析時，表面具有87%的C，而O與Si則分別為10%與3%。在商業品Si/SiOx/Gr之部分因為Si、SiOx及Gr為物理混摻，可以觀察到其O與Si之含量較高，分別為15%與11%，但Si含量仍較實施例3低，推估此商業品Si、SiOx及Gr進行物理混合完後仍有進一步的碳包覆製程。實施例8之結果顯示與比較例6在C,O,Si之比較是相近的。經表面改質之樣品c-SiOxMLG@Si@Gr在C,O,Si之分析結果可以看到與商業品SiOx(commercial)相近，此部分也驗證本專利液相製程可製作出與高溫氣相法生成SiOx再以CVD碳包覆之類似結構組成表面。 Please refer to Figure 21, which is a spectrum analysis diagram of XPS Si2p in Example 11 (c-SiOxMLG@Si@Gr) of the present invention. Please refer to Figure 22, which is a comparative example 6 of the present invention. (Si/SiOx/Gr(commercial)) XPS Si2p spectrum analysis graph, valence peak Si0 is 99.6eV, Si+1 is 100.1eV, Si+2 is 101.5eV, Si+3 is 102.9eV, Si +4 is 103.9eV. The valence distribution of the Si/SiOx/Gr material Si from the two compared with the commercial product ranges from 4 to 0, which is similar to the result of Example 3 (Figure 8), but because the 0 valence Si is easy to be electrolyzed on the surface Liquid reaction, so the presence of 0-valent Si on the surface will make the battery life worse. The result of Example 11 shows that the analysis result of the surface valence is mainly Si3+, and has a small amount of 2 and 4 valences. The surface composition is different from commercial SiOx or Si/SiOx/Gr mixed materials. . Table 5 is XPS full spectrum scanning comparative example 1 (SiOx (commercial)), comparative example 6 (Si/SiOx/Gr (commercial)), example 8 (SiOxMLG@Si@Gr) and example 11 (c-SiOxMLG@Si@Gr ) Semi-quantitative analysis of C, O, Si. Comparative Example 1 mentioned earlier that it is SiOx for CVD carbon coating. Therefore, when performing XPS surface analysis, the surface has 87% C, while O and Si are 10% and 3%, respectively. In the commercial product Si/SiOx/Gr part because Si, SiOx and Gr are physically mixed, it can be observed that the content of O and Si are higher, 15% and 11%, respectively, but the Si content is still lower than that of Example 3. It is estimated that this commercial product Si, SiOx and Gr will still have a further carbon coating process after physical mixing. The result of Example 8 shows that it is similar to that of Comparative Example 6 in terms of C, O, and Si. The surface-modified sample c-SiOxMLG@Si@Gr can be found to be similar to commercial SiOx (commercial) in the analysis results of C, O, Si. This part also verifies that the patented liquid phase process can be produced with high temperature gas phase Method to generate SiOx and then CVD carbon coated similar structure to form the surface.
請參閱第二十三圖所示，為本發明比較例4(10wt% SiOx(commercial)+90%wt NG)，實施例6(10wt% Si/SiOx/MLG/C+90%wt MCMB)，實施例7(10wt% Si/SiOxMLG/C+90%wt NG)，實施例12(50wt% c-SiOxMLG@Si@Gr+50wt% NG)之半電池長循環充放電測試圖，操作電壓範圍為0.01~1.5V，如圖所示，前5圈充放電循環速率為0.1C(結果未顯示於圖中，但第一圈數據列於表二)，長圈數壽命測試(後續100圈)電流大小為0.5C(1C=450mA g-1)。壽命最佳之樣品為實施例12(50wt% c-SiOxMLG@Si@Gr+50wt% NG)相較於商業品比較例4(10wt% SiOx(commercial)+90%wt NG)在可逆電容量、首圈庫倫效率以及100圈0.5C速率之充放電測試壽命結果皆較佳。其中比較例4之商業品SiOx雖然有不錯的壽命，但其首圈庫倫效率僅85.4%，目前大多電芯廠對低於90%之首圈庫倫效率負極材料是無法使用的，或者需要進行預鋰化(於活化過程前，預先將鋰離子儲存於負極中，減少鋰離子於活化過程中之消耗)之製程(技術與設備皆較困難)。 Please refer to Figure 23, which is Comparative Example 4 of the present invention (10wt% SiOx(commercial)+90%wt NG), Example 6 (10wt% Si/SiOx/MLG/C+90%wt MCMB), Example 7 (10wt% Si/SiOxMLG/C+90%wt NG), Example 12 (50wt% c-SiOxMLG@Si@Gr+50wt% NG) The half-cell long-cycle charge and discharge test chart, the operating voltage range is 0.01~1.5V, as shown in the figure, the first 5 cycles of charge and discharge cycle rate is 0.1C (the results are not shown in the figure, but the first cycle data is listed in the table Two), the long cycle life test (following 100 cycles) current is 0.5C (1C=450mA g-1). The sample with the best lifetime is Example 12 (50wt% c-SiOxMLG@Si@Gr+50wt% NG) compared to commercial product Comparative Example 4 (10wt% SiOx(commercial)+90%wt NG) in reversible capacitance, The first cycle Coulomb efficiency and 100 cycles of 0.5C rate of charge and discharge test life results are better. Although the commercial SiOx of Comparative Example 4 has a good lifespan, its first-cycle coulombic efficiency is only 85.4%. At present, most battery cell manufacturers cannot use negative electrode materials with a first-cycle coulomb efficiency of less than 90%, or require pre-processing. Lithization (pre-store lithium ions in the negative electrode before the activation process to reduce the consumption of lithium ions during the activation process) process (technical and equipment are more difficult).
請參閱第二十四圖所示，為本發明實施例9(15wt% SiOxMLG@Si+85wt% NG)，實施例10(SiOxMLG@Si@Gr)，實施例11(c-SiOxMLG@Si@Gr)，比較例5(15wt% SiOx(commercial)+85wt% NG)，比較例6(Si/SiOx/Gr(commercial))之半電池長循環充放電測試圖，操作電壓範圍為0.01~1.5V，前5圈充放電循環速率為0.1C(結果未顯示於圖中，但第一圈數據列於表三)，長圈數壽命測試 (後續100圈)電流大小為0.5C(1C=550mA/g)。壽命最佳之樣品為實施例11(c-SiOxMLG@Si@Gr)，0.5C速率下充放電100圈後電容量仍可維持88%，相較於兩個商業品比較例5(15wt% SiOx(commercial)+85wt% NG)與比較例6(Si/SiOx/Gr(commercial))高出5~6%，而三者首圈庫倫效率皆為~89%。最主要之改善在藉由降低表面之Si含量以及Si0+之比例，並且藉由具孔洞結構之材料吸收Si的體積膨脹改變並且由表面改質進一步使比表面積下降，使得此一材料在目前商業產品下有高度之競爭力。 Please refer to Figure 24, which is the embodiment 9 (15wt% SiOxMLG@Si+85wt% NG), the embodiment 10 (SiOxMLG@Si@Gr), and the embodiment 11 (c-SiOxMLG@Si@Gr) of the present invention. ), comparative example 5 (15wt% SiOx(commercial)+85wt% NG), comparative example 6 (Si/SiOx/Gr(commercial)) half-cell long cycle charge and discharge test chart, the operating voltage range is 0.01~1.5V, The first 5 cycles of charge and discharge cycle rate is 0.1C (the results are not shown in the figure, but the data of the first cycle are listed in Table 3), long cycle life test (The next 100 turns) The current is 0.5C (1C=550mA/g). The sample with the best lifespan is Example 11 (c-SiOxMLG@Si@Gr). After 100 cycles of charge and discharge at a rate of 0.5C, the capacitance can still maintain 88%. Compared with the two commercial products in Comparative Example 5 (15wt% SiOx (commercial)+85wt% NG) and Comparative Example 6 (Si/SiOx/Gr(commercial)) are 5~6% higher, and the first lap coulombic efficiency of the three is ~89%. The most important improvement is to reduce the Si content and the ratio of Si0+ on the surface, and to absorb the volume expansion change of Si by the porous structure material and further reduce the specific surface area by surface modification, making this material in the current commercial products There is a high degree of competitiveness.
本發明所提出之材料與商業化產品SiOx或是Si/SiOx/Gr，首圈庫倫效率是相近的，但可逆電容量與充放電循環壽命相較於商業化產品都是本專利之負極材料較佳。此外，溶液法在工業製程上相較於氣相法是相對容易量產與控制的，製程所需熱處理溫度(900oC以下)也較高溫氣相法(900~1700oC)低許多，且高溫氣相法還需控制其反應器中之壓力，並且需要CVD技術進行二次碳包覆。反觀本專利之製程，在製作過程中即混入碳源，而達到一步驟之合成，也避開目前主流矽負極材料之碳包覆製程(濕式溶劑法)。 The material proposed in the present invention is similar to the commercial product SiOx or Si/SiOx/Gr, and the first lap coulombic efficiency is similar, but the reversible capacitance and charge-discharge cycle life are compared with the commercial product. good. In addition, the solution method is relatively easy to mass produce and control in the industrial process compared to the gas phase method. The heat treatment temperature (below 900oC) required for the process is also much lower in the higher temperature gas phase method (900~1700oC), and the high temperature gas phase method The method also needs to control the pressure in the reactor, and requires CVD technology for secondary carbon coating. In contrast, the manufacturing process of this patent mixes a carbon source during the manufacturing process to achieve a one-step synthesis, which also avoids the current mainstream silicon anode material carbon coating process (wet solvent method).
本發明之氧化亞矽負極材料，以矽為原料進行鹼蝕刻並以濕式球磨將MLG包覆於殘留Si表面，並且最後再以有機裂解碳層進行包覆使得Si/SiOx能均勻分布在複合材料中，MLG與SiOx減緩Si因充放電造成的體積膨脹效應與破 裂情形。最後再將此一複合材料製作於石墨表面作為負極材料使用，期望可藉由較大多數之石墨來共同吸收Si或SiOx之體積膨脹，進而使其壽命延長。表面之非晶相碳改質，使原始材料表面由多孔特性改質為光滑表面，同時降低了比表面積，也對首圈庫倫效率以及壽命有所改善。 The siliceous oxide negative electrode material of the present invention uses silicon as a raw material for alkali etching and wet ball milling to coat the surface of residual Si with MLG, and finally is coated with an organic cracked carbon layer so that Si/SiOx can be evenly distributed in the composite Among the materials, MLG and SiOx slow down the volume expansion effect and destruction of Si caused by charging and discharging. Rift situation. Finally, this composite material is fabricated on the surface of graphite and used as a negative electrode material. It is hoped that more graphite can absorb the volume expansion of Si or SiOx together, thereby prolonging its life. The surface modification of amorphous carbon makes the surface of the original material changed from porous to smooth surface. At the same time, it reduces the specific surface area, and also improves the first-lap Coulomb efficiency and life.
在比較物化特性上，日本商業化產品之SiOx為Si2+為主之材料，在首圈充放電過程中會形成Li2O與Li4SiO4兩者非活性之物質，使其首圈庫倫效率較低。而本產品由於可保留部分Si0+使首圈庫倫效率較高，可以看到商業化產品Si/SiOx/Gr(commercial)此樣品即使用此概念來提升其首圈庫倫效率。目前電芯廠對高容量之負極材料要求，至少首圈庫倫效率要在~90%或以上。 In terms of physical and chemical characteristics, the SiOx of Japanese commercial products is mainly Si 2+ . During the first cycle of charging and discharging, both Li 2 O and Li 4 SiO 4 are formed as inactive substances, making the first cycle of Coulomb. The efficiency is low. However, this product can retain some Si 0+ to make the first lap coulomb efficiency higher. It can be seen that this sample of the commercial product Si/SiOx/Gr (commercial) uses this concept to improve its first lap coulomb efficiency. At present, battery cell factories require high-capacity anode materials, at least the first lap coulombic efficiency should be ~90% or above.
材料成本評估(以c-SiOxMLG@Si@Gr為例)：電費以1度電3塊錢計算，目前生產粉體為每批次1kg實驗室級。高溫爐900oC，使用功率4000W，時間8小時，耗用電費144元/公斤-樣品。純度99.99%之氮氣使用成本~16元/公斤-樣品。機械球磨，使用功率400W，時間6小時，耗用電費~7元/公斤-樣品。氫氧化鈉、檸檬酸、葡萄糖、去離子水等化學藥品~10元/公斤-樣品。0.7μm-Si粉成本340元/公斤-含量佔c-SiOxMLG@Si@Gr產品之16%。石墨負極材料成本300元/公斤-含量佔c-SiOxMLG@Si@Gr產品之83%。自製多層石墨烯成本600元/公斤-含量佔c-SiOxMLG@Si@Gr產品之1%。因
此生產c-SiOxMLG@Si@Gr每公斤材料成本為486元，但此部分還以實驗室材料成本計算，若放量進行試量產採用工業級量產之材料製作，成本可再降低。
Material cost assessment (take c-SiOxMLG@Si@Gr as an example): The electricity fee is calculated at 3 yuan per kilowatt-hour, and the current production of powder is 1kg laboratory grade per batch. The high temperature furnace is 900oC, the power is 4000W, the time is 8 hours, and the electricity consumption is 144 yuan/kg-sample. The cost of using nitrogen with a purity of 99.99% is ~16 yuan/kg-sample. Mechanical ball mill, use power 400W,
目前市場上較好且具產能的SiOx(commercial)為日本大廠所生產之產品，其價格約在3000元/公斤與85%石墨混合(比較例5)之負極材料其單價為705元/公斤。此外，Si/SiOx/Gr(commercial)為商售之550mAh/g之產品，其單價為1200元/公斤。而本專利所提出之生產方式，材料成本為486元/公斤，僅為SiOx(commercial)混石墨單價的69%及Si/SiOx/Gr(commercial)單價的41%，但特性相較兩者商業化產品，本專利之樣品皆較佳。總體來說，以550mAh/g之樣品來比較，使用本專利所生產之負極材料，成本下降40~60%，首圈庫倫效率提升0.6~5.3%，0.5C速率下充放電循環100圈後電容量保持率提升5~6%。 SiOx (commercial), which is currently on the market and has a good capacity, is a product produced by a large Japanese factory, and its price is about 3000 yuan/kg mixed with 85% graphite (comparative example 5), and its unit price is 705 yuan/kg . In addition, Si/SiOx/Gr (commercial) is a commercial product of 550mAh/g, and its unit price is 1200 yuan/kg. The production method proposed in this patent has a material cost of 486 yuan/kg, which is only 69% of the unit price of SiOx (commercial) mixed graphite and 41% of the unit price of Si/SiOx/Gr (commercial). Chemical products, the samples of this patent are all better. In general, compared with the sample of 550mAh/g, using the anode material produced by this patent, the cost is reduced by 40~60%, the first cycle of coulombic efficiency is increased by 0.6~5.3%, and the charge and discharge rate is charged after 100 cycles at 0.5C. The capacity retention rate is increased by 5 to 6%.
在生產設備部分，使用之高溫爐僅需900℃於氮氣氣氛，相較於900~1700℃真空爐並且需精準控制其生產壓力之設備建置成本也較低。另外，不需要使用二次碳包覆之技術，於合成過程中即把碳源混入，減少CVD設備或其他碳包覆所需之設備成本。 In the production equipment part, the high-temperature furnace used only requires 900°C in a nitrogen atmosphere. Compared with the 900~1700°C vacuum furnace and requires precise control of the production pressure, the equipment construction cost is also lower. In addition, there is no need to use secondary carbon coating technology, and the carbon source is mixed in during the synthesis process, reducing the cost of CVD equipment or other equipment required for carbon coating.
上述之實施例僅為例示性說明本創作之特點及功效，非用以限制本創作之實質技術內容的範圍。任何熟悉此技藝之人士均可在不違背創作之精神及範疇下，對上述實 施例進行修飾與變化。因此，本創作之權利保護範圍，應如後述之申請專利範圍所列。 The above-mentioned embodiments are merely illustrative to illustrate the characteristics and effects of this creation, and are not intended to limit the scope of the essential technical content of this creation. Anyone familiar with this technique can, without violating the spirit and scope of creation, comment on the above-mentioned facts. The examples are modified and changed. Therefore, the scope of protection of the rights of this creation should be listed in the scope of patent application described later.
1‧‧‧複合材料 1‧‧‧Composite materials
2‧‧‧核心 2‧‧‧Core
4‧‧‧複合材料層 4‧‧‧Composite material layer
41‧‧‧孔洞 41‧‧‧Hole
6‧‧‧外殼 6‧‧‧Shell
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