Electrochemical Investigations of Li2Fe0.8-xMn0.2MxSiO4 (M = Mg2+, Zn2+) Cathodes for Lithium Ion Batteries

[摘要] The Mn2+ and Mg2+ (or Zn2+) co-doped Li2Fe0.8-xMn0.2MxSiO4 (x = 0.05 and 0.1) are synthesized by a solid-state reaction route. Compared with the single doped Li2Fe0.8Mn0.2SiO4, the co-doped samples show improved cycling performance. The capacity retention can stay above 50% after 50 cycles, which is significantly higher than 30.4% for Li2Fe0.8Mn0.2SiO4. This phenomenon could be attributed to the increased structural stability caused by the incorporation of the electrochemically inactive M2+ ions. However, except for Li2Fe0.75Mn0.2Mg0.05SiO4, the other samples show decreased capacities, especially in the case of the Mn/Zn co-doping. Further tests indicate that the promotion of Li+ diffusivity may be a

[学科分类] 化学（综合）

[关键词] Â chemically modified electrode;lithium battery;applied electrochemistry;composite and nanocomposite materials