LiMn_(2-2x)Co_xCr_xO_(3.95)F_(0.05)正极材料的合成表征及表面包覆  

Surface modification of cathode material LiMn_(2-2x)Co_xCr_xO_(3.95)F_(0.05) for lithium ion batteries

作　　者：资利云[1] 李敏[1] 李荣华[1] 王文继[1] 

机构地区：[1]福州大学化学化工学院,福建福州350002

出　　处：《福州大学学报（自然科学版）》2007年第6期914-919,共6页Journal of Fuzhou University(Natural Science Edition)

基　　金：福建省自然科学基金资助项目(U0750008);福建省科技三项资助项目(K04012)

摘　　要：采用溶胶-凝胶法合成了锂锰尖晶石正极材料LiMn2-2xCoxCrxO3.95F0.05(x=0.05、0.1),并用沉淀法在其表面包覆2%的TiO2.XRD和ESEM分析表明掺杂样品以及掺杂之后再包覆TiO2的样品依然保持尖晶石结构,样品颗粒大小分布都较均匀.电化学性能测试显示LiMn2O4的首次放电容量为124.4 mA.h/g,50次循环后容量损失43.2%,而多元掺杂样品LiMn1.9Co0.05Cr0.05O3.95F0.05和LiMn1.8Co0.1Cr0.1O3.95F0.05的初始放电容量分别为114.7和103.4 mA.h/g,100次循环后容量损失为9.7%和4.1%.LiMn1.9Co0.05Cr0.05O3.95F0.05包覆2%TiO2和LiMn1.8Co0.1Cr0.1O3.95F0.05包覆2%TiO2样品的初始放电容量为109.3和96.6 mA.h/g,100次循环后容量损失为5.0%和3.5%,经过改性后材料的循环性能得到改善.LiMn2-2xCoxCrxO3.95F0.05 was prepared by the sol -gel method and coated with 2% TiO2 by preciptitation way. The results of XRD and ESEM indicated that the doped samples and coated TiO2 samples kept spinel structure, as well as patiticles of the samples are well - distributed. From the charge and discharge measurement, the loss of capacity for LiMn2O4 was 43.2% after 50 cycles with a first discharge capacity of 124.4 mA· h/g. For multi - doped samples, the discharge capacity of LiMn1.9Co0.05Cr0.05O3.95F0.05 and LiMn1.8Co0. 1Cr0.1O3.95F0.05 respectively was 114.7 and 103.4 mA · h/g, the loss of capacity was 9.7% and 4.1% after 100 cycles. The discharge capacity of 2% TiO2 coated LiMnl.9Co0.05Cr0.05O3.95 F0.05 and 2% TiO2 coated LiMnl.8Co0. 1Cr0.1 O3.95 F0.05 respectively was 109.3 and 96.6 mA · h/g, the loss of capacity was 5.0% and 3.5% after 100 cycles. Material circulation performance was obviously improved by modified LiMn2O4.

关 键 词：正极材料 包覆 掺杂 锂离子电池 

分 类 号：O646.1[理学—物理化学]