【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.更多还原

【Abstract】 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 LiMn1.9Co0.05Cr0.05O3.95F0.05 and 2% TiO2 coated LiMn1.8Co0.1Cr0.1O3.95F0.05 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.更多还原