锂离子正极三剑客之一:钴酸锂
1,LiCoO2的一种组成办法
900℃
2Co3O4+3Li2Co3+1/2O2 ——— 6LiCoO2+3CO2 ↑
8hr
2,LiCoO2的结构对锂离子电池循环功能影响
LiCoO2归于α-NaFeO2型结构,它具有二维层状结构,适合锂离子的脱嵌。LiCoO2中含有微量Fe,Ni等,當Li+有序化/無序化轉變時,Fe,Ni等雜質將替代Co晶格上的Co原子,則層狀結構變壞,影響也LiCoO2的充放電功能.
LiCoO2粒度巨细對初次放電容量影響不大,而粒度散布越寬,其循環性越差;當D50(粒度尺度)=5.19μm且会集粒度散布在3-8μm時,LiCoO2達到最佳的放電容量及循環性.
當粒度散布較寬時,LiCoO2多孔電極孔隙度則差,影響其對電解液的毛細效果,使其阻抗較大;别的,當充至極限電位時,大颗粒LiCoO2外表Li+會過脫嵌而破壞层狀結構.這兩種原因使粒度散布寬的LiCoO2循環性差.
3,德国MERCK公司LiCoO2的标准:
形状:Lithium Cobalt Oxide
色彩:黑色粉末(Black Powder)
ParTIcle Size:D50≈36μm
Specific Surface Area:2m2/g(BET)
Tap Density:2Kg/l
Specific Capacity:min 130mAh/g(3 Cycle,3.3–4.3 vs. Li)
Cell Design:
Cell Type :Button Cell (Dia. 20mm)
Anode :Lithium Metal
Electrolyte: Liquid Battery Electrolyte ,EC:DMC=50:50 wt%,1M LiPF6
Cathode: AcTIve Powder : Carbon Black : PTFE=85:10:5 mix
Cathode Current Collector: Aluminium Foil
Test CondiTIons: Charge :C/7; Discharge : D/7
PotenTIal Range; 3.3—4.3V vs.Li