LiFe_0.95Ni_0.02Mn_0.03PO₄/C的合成及电化学性能

吴 强，王先友，舒洪波，杨顺毅，王英平，杨秀康，白艳松，魏启亮

(湘潭大学 化学学院 环境友好化学与应用教育部重点实验室，湘潭 411105)

摘 要：采用高温固相法合成Ni²⁺、Mn²⁺共掺杂的LiFe_0.95Ni_0.02Mn_0.03PO₄/C正极材料。通过X射线衍射(XRD)、扫描电镜(SEM)、电化学阻抗谱(EIS)和电化学测试技术等研究材料的结构、形貌和电化学性能。结果表明：Ni²⁺和Mn²⁺共掺杂后的LiFe_0.95Ni_0.02Mn_0.03PO₄/C材料仍然具有LiFePO₄/C橄榄石型晶体结构，且掺杂后材料的放电比容量和循环性能都得到显著改善。在0.1C和1C下放电时，未掺杂LiFePO₄/C的首次放电比容量仅分别为153和140 mA·h/g，而Ni²⁺、Mn²⁺共掺杂的LiFe_0.95Ni_0.02Mn_0.03PO₄/C材料首次放电比容量分别为165和145 mA·h/g，且在1C下循环100次后容量保持率仍然为97.6%。

关键词：锂离子电池；正极材料；金属离子共掺杂；电化学性性能

Synthesis of LiFe_0.95Ni_0.02Mn_0.03PO₄/C and its electrochemical properties

WU Qiang, WANG Xian-you, SHU Hong-bo, YANG Shun-yi, WANG Ying-ping, YANG Xiu-kang, BAI Yan-song, WEI Qi-liang

(School of Chemistry, Key Laboratory of Environmentally Friendly Chemistry and Applications,
Ministry of Education, Xiangtan University, Xiangtan 411105, China)

Abstract:LiFe_0.95Ni_0.02Mn_0.03PO₄/C cathode material co-doped by Ni²⁺ and Mn²⁺ ions, was prepared by high temperature solid phase method. The structure, morphology and electrochemical properties of the as-prepared material were characterized by XRD, SEM, EIS and charge-discharge methods. The results show that the as-prepared LiFe_0.95Ni_0.02Mn_0.03PO₄/C keeps the olivine structure of LiFePO₄/C, and the discharge specific capacity and cyclic stability are obviously enhanced. The initial discharge capacities of LiFePO₄/C without doping are only 153 and 140 mA·h/g at 0.1C and 1C, respectively. While the initial discharge capacities of LiFe_0.95Ni_0.02Mn_0.03PO₄/C co-doped with Ni²⁺ and Mn²⁺ are 160 and 145 mA·h/g at 0.1C and 1C, respectively. Besides, the capacity retention still has 97.6% after 100 cycles.

Key words:lithium-ion battery; cathode material; metal ions co-doping; electrochemical properties