为了研究非金属元素包覆和金属元素掺杂对LiFePO4的电化学性能和振实密度的影响,用固相反应法制备了炭包覆的LiFePO4/C和铜掺杂的LiFe0.95Cu0.05PO4正极材料,并对所制材料进行了XRD、SEM、充放电循环、倍率性能和振实密度的测试。结果显示:LiFePO4/C和LiFe0.95Cu0.05PO4的循环平均容量分别达到147mAh/g和131mAh/g;在高倍率放电时,LiFe0.95Cu0.05PO4的容量衰减远大于LiFePO4/C。LiFePO4/C材料的各项电化学性能都优于LiFe0.95Cu0.05PO4材料,而LiFe0.95Cu0.05PO4材料的振实密度远大于LiFePO4/C材料的振实密度,前者是后者的1.5倍。
The effects of a carbon coating and copper doping on the electrochemical performance and tap density of a LiFePO4 cathode for lithium ion batteries were investigated by XRD,SEM,charge/discharge cycle tests,rate tests and tap density tests. Results showed that the average discharge capacity of LiFePO4/C and LiFe0.95Cu0.05PO4 were 147 mAh/g and 131 mAh/g respectively. The capacity fading rate of LiFe0.95Cu0.05PO4 was much larger than that of LiFePO4/C in a high-rate discharging test. The electrochemical performance of LiFePO4/C was better than that of LiFe0.95Cu0.05PO4 , but the tap density of the latter was 1.5 times as large as that of the former.