Uniform AlF_3 thin layer to improve rate capability of LiNi_(1/3)Co_(1/3) Mn_(1/3)O_2 material for Li-ion batteries  

作　　者：王海燕 唐爱东 黄可龙 刘素琴 

机构地区：[1]School of Chemistry and Chemical Engineering,Central South University

出　　处：《Transactions of Nonferrous Metals Society of China》2010年第5期803-808,共6页中国有色金属学报（英文版）

基　　金：Project(50542004) supported by the National Natural Science Foundation of China;Project(1960-71131100017) supported by Graduate Degree Thesis Innovation Foundation of Central South University,China

摘　　要：LiNi1/3Co1/3Mn1/3O2 was coated with uniform nano-sized AlF3 layer by chemical precipitation method to improve its rate capability.The samples were characterized by X-ray diffractometry (XRD),transmission electron microscopy (TEM),energy dispersive spectroscopy (EDS),charge-discharge cycling,cyclic voltammetry (CV),and electrochemical impedance spectroscopy (EIS).Uniform coated layer with a thickness of about 3 nm was observed on the surface of LiNi1/3Co1/3Mn1/3O2 particle by TEM.At 0.5C and 2C rates,1.5% (mass fraction) AlF3-coated LiNi1/3Co1/3Mn1/3O2/Li in 2.8-4.3 V versus Li/Li+ after 80 cycles showed less than 3% of capacity fading,while those of the bare one were 16.5% and 45.9%,respectively.At 5C rate,the capacity retention of the coated sample after 50 cycles maintained 91.4% of the initial discharge capacity,while that of the bare one decreased to 52.6%.EIS result showed that a little change of charge transfer resistance of the coated sample resulting from uniform thin AlF3 layer was proposed as the main reason why its rate capability was improved obviously.CV result further indicated a greater reversibility for the electrode processes and better electrochemical performance of AlF3-coated layer.LiNi1/3Co1/3Mn1/3O2 was coated with uniform nano-sized AlF3 layer by chemical precipitation method to improve its rate capability.The samples were characterized by X-ray diffractometry （XRD）,transmission electron microscopy （TEM）,energy dispersive spectroscopy （EDS）,charge-discharge cycling,cyclic voltammetry （CV）,and electrochemical impedance spectroscopy （EIS）.Uniform coated layer with a thickness of about 3 nm was observed on the surface of LiNi1/3Co1/3Mn1/3O2 particle by TEM.At 0.5C and 2C rates,1.5% （mass fraction） AlF3-coated LiNi1/3Co1/3Mn1/3O2/Li in 2.8-4.3 V versus Li/Li＋ after 80 cycles showed less than 3% of capacity fading,while those of the bare one were 16.5% and 45.9%,respectively.At 5C rate,the capacity retention of the coated sample after 50 cycles maintained 91.4% of the initial discharge capacity,while that of the bare one decreased to 52.6%.EIS result showed that a little change of charge transfer resistance of the coated sample resulting from uniform thin AlF3 layer was proposed as the main reason why its rate capability was improved obviously.CV result further indicated a greater reversibility for the electrode processes and better electrochemical performance of AlF3-coated layer.

关 键 词：Li-ion battery LINI1/3CO1/3MN1/3O2 coating uniform thin AlF3 layer rate capability 

分 类 号：TM912[电气工程—电力电子与电力传动]