锂源对LiFePO4组织结构及电化学性能的影响

摘要

利用不同的锂化合物Li2CO3、LiOH.H2O、LiNO3、LiF作为锂源,采用二步固相法合成了LiFePO4/C,研究了不同锂源对LiFePO4组织结构和电化学性能的影响。结果表明,在相同的合成工艺条件下,采用4种不同锂源合成的LiFePO4的电化学性能表现出明显差异。采用LiOH.H2O合成的LiFe-PO4的电化学性能最佳,0.1C下的放电比容量为161mAh/g,1C下的放电比容量达117mAh/g,且0.5C下循环容量无衰减。采用不同锂源合成的LiFePO4电化学性能差异的原因与LiFePO4的颗粒大小、粒径分布、团聚程度及是否存在杂相有直接关系。%LiFePO4/C composites were synthesized by two step solid reaction process using Li2CO3,LiOH·H2O,LiNO3,LiF as Lisources.It was found that LiFePO4/C composites prepared with different Li-containing compounds exhibited obvious differences in the microstructure and electrochemical performance.LiFePO4/C synthesized by LiOH·H2O showed the best electrochemical property,with a high discharge capacity of 161mAh/g at 0.1C,117mAh/g at 1C and excellent cycle stability.The different electrochemical performances of LiFePO4/C composites by different Lisources may be contributed to their difference in the particle size,particle size distribution,degree of agglomeration and purity.