包覆碳掺CoLiFePO4正极的电化学性能研究

Electrochemical Performances of C-Coating and Co-Doping LiFePO_4

应用水热法在200℃下合成了橄榄石结构LiFePO4正极材料,合成过程中添加蔗糖作为包覆用碳源,并同时掺Co.实验表明,包覆碳掺Co能更有效地改善LiFePO4电极的电化学性能.样品可后退火处理,400℃退火LiFePO4样品结晶度和颗粒尺寸均影响其电化学性能.包覆碳掺Co LiFePO4样品可使颗粒细化,改善电极倍率性能.

Phospho-olivine LiFePO4 cathode materials were prepared by hydrothermal reaction at 200 ℃.Sucrose was added as C-coating resource and Co was doped into the crystal lattice of LiFePO4.In order to investigate the improvements in the electrochemical properties of Co-doped LiFePO4,three samples,LiFePO4,C-coated LiFePO4 and C-coating-Co-doped LiFePO4,were synthesized under the same preparation conditions.Charge/discharge studies reveal that the Co-doped LiFePO4/C composite annealed at 400 ℃ exhibits marked improvement of specific capacity by diminishing the particle sizes and enhancement in the degree of crystallinity.The C-coating and Co-doped into the LiFePO4 crystal lattices improve the rate performance through the reduction of the particle sizes.