【摘要】 用水热法制备LiFe_0.95M_0.05PO₄（M=Mg,Ni,Co）,研究了掺杂对材料电化学性能的影响.结果表明,液相Fe位掺杂合成的LiFe_0.95M_0.05PO₄具有纯相橄榄石结构、结晶良好、粒径均匀;Fe位掺杂可增强材料的可逆性和导电性,提高其1C倍率下的电化学容量和循环稳定性;LiFe_0.95Mg_0.05PO₄,LiFe_0.95Ni_0.05PO₄和LiFe_0.95Co_0.05PO₄三种材料的1C倍率首次放电比容量分别为133.1 mAh·g^-1,128.4 mAh·g^-1和135.2 mAh·g^-1;三种掺杂离子中Co²⁺掺杂的效果最好,0.1C和1C倍率放电循环30次后的容量衰减率仅为5.7%和9.5%.更多还原

【Abstract】 LiFe_0.95M_0.05PO₄（M=Mg,Ni,Co） were synthesized by hydrothermal process with Fe-site doping in liquid phase.The samples of LiFe_0.95M_0.05PO₄ were characterized by XRD,FTIR and SEM methods.The effect of Fe-site doping on electrochemical properties of the samples was investigated.The results show that the electrochemical capacity and cyclic stability of LiFe_0.95M_0.05PO₄ at 1C are enhanced. Under 1C rate,the first discharge capacity of LiFe_0.95Mg_0.05PO₄,LiFe_0.95Ni_0.05PO₄ and LiFe_0.95Co_0.05PO₄ exhibit 133.1 mAh·g^-1,128.4 mAh·g^-1 and 135.2 mAh·g^-1,respectively.In three doping ions,the result of Co²⁺ doping is the best.The capacity fading rates of LiFe_0.95Co_0.05PO₄ are 5.7%at 0.1C and 9.5% at 1C after 30 cycles.Such a significant improvement of electrochemical performance at 1C rate should be related to the enhancement of the reversibility and conductivity of LiFePO₄ doped by bivalent cation in Fe-site.更多还原