摘要
钴酸锂因其高体积能量密度、优异的倍率容量和良好的循环性能,是3C类电子产品的主导正极材料,且目前实际应用的钴酸锂材料克容量约为理论容量的65%,还具有进一步开发的潜力。采用溶胶–凝胶法对正极材料LiCoO_(2)进行锂离子导体材料LiAlSiO_(4)包覆,研究了LiAlSiO_(4)及热处理温度对材料结构、形貌和电化学性能的影响。结果表明:热处理过程中Al^(3+)可进入LiCoO_(2)晶格,形成固溶体LiCoO_(2)Al_(x)O_(2)LiAlSiO_(4)在钴酸锂颗粒表面形成惰性的包覆层,有效地改善了钴酸锂材料在高电压下的循环和倍率性能。当热处理温度为600℃时,LiAlSiO_(4)包覆的钴酸锂材料综合性能达到最优。该样品在2.75~4.55 V的电压范围内,0.5 C倍率下室温放电比容量为209.3 m A·h/g,50次循环后的放电比容量为201.6 m A·h/g(容量保留率96.3%),且在8 C倍率下依然能释放出160.0 m A·h/g的比容量。
Lithium cobalt oxide is a leading cathode material for 3C electronic products because of its high bulk energy density,excellent rate capacity and good cycle performance.The existing gram capacity of lithium cobalt oxide material in practical application is approximately 65%of the theoretical capacity,and this material has a potential for further development.In this paper,a lithium ion cobalt oxide cathode material was coated with lithium ion conductor material LiAlSiO_(4)by a sol–gel method.The effects of LiAlSiO_(4)and heat treatment temperature on the structure,morphology and electrochemical properties of the material were investigated.The results show that during the heat treatment,Al^(3+)enters the LiCoO_(2)lattice to form a solid solution LiCoO_(2)Al_(x)O_(2),and an inert coating layer is formed on the surface of the lithium cobalt oxide particles LiAlSiO_(4)coating,effectively improving the cycle and rate performance of the lithium cobalt oxide material at a high voltage.The optimum overall performance of the lithium cobalt oxide material coated with LiAlSiO_(4)can be obtained at a heat treatment temperature of 600℃.In a voltage range of2.75–4.55 V,the specific discharge capacity at room temperature at 0.5 C rate is 209.3 m A·h/g,and the discharge specific capacity after 50 cycles is 201.6 m A·h/g(at a capacity retention rate of 96.3%),and the specific capacity is 160.0 m A·h/g at 8 C.
作者
申斌
徐星
刘万民
秦牡兰
王伟刚
SHEN Bin;XU Xing;LIU Wanmin;QIN Mulan;WANG Weigang(College of Materials and Chemical Engineering,Hunan Institute of Engineering,Xiangtan 411100,Hunan,China;State Key Laboratory of Advanced Chemical Power Sources,Guizhou Meiling Power Sources Co.Ltd.,Zunyi 563003,Guizhou,China)
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2022年第5期1201-1208,共8页
Journal of The Chinese Ceramic Society
基金
湖南省教育厅科研项目(19A111,20C0490)
湖南省自然科学基金(2021JJ30183)。
关键词
锂离子电池
钴酸锂
硅酸铝锂
高电压
包覆改性
lithium-ion battery
lithium cobalt oxide
lithium aluminum silicate
high voltage
coating modification
