Structural Basis for High-rate Capability of Cathode Material Li_(0.1)Fe_(0.9)Mg_(0.1)PO_4
- 2009年第15卷 
应用高温固相反应合成锂离子电池正极材料LiFePO4和LiFe0.9Mg0.1PO4.不同浓度的K2S2O8水溶液氧化LiFe0.9Mg0.1PO4制备部分脱锂两相混合物Li0.4Fe0.9Mg0.1PO4及完全脱锂单相化合物Li0.1Fe0.9Mg0.1PO4.X射线衍射物相分析(XRD),选区电子衍射(SAED)和高分辨原子图像(HRTEM)测试表明,脱锂相Li0.1Fe0.9Mg0.1PO4是单相化合物,没有发生相分离.点阵参数计算表明,LiFe0.9Mg0.1PO4体系嵌锂相和脱锂相的晶格错配度与LiFePO4体系相比有所降低,这正是锂离子电池正极材料LiFe0.9Mg0.1PO4具有高倍率循环充放电比容量的结构基础.Cathode materials LiFePO4 and LiFe0.9Mg0.1PO4 for lithium ion batteries were synthesized by a solid state reaction. Chemical oxidation to obtain Li0.4Fe0.9Mg0.1PO4 and Li0.1Fe0.9Mg0.1PO4 was carried out by reacting LiFe0.9Mg0.1PO4 with K2S2O8 solution of different concentration. Li0.1Fe0.9Mg0.1PO4 was confirmed to be a single phase compound with no impure phases,investigated by X-ray diffraction (XRD),selected area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM) techniques. Calculated lattice parameter results showed decreased lattice misfit between lithiated LiFe0.9Mg0.1PO4 and delithiated Li0.1Fe0.9Mg0.1PO4,compared lattice misfit between LiFePO4 and FePO4. It was considered the decreased lattice misfit as the structural basis for optimized high-rate capability of cathode material LiFe0.9Mg0.1PO4 for lithium ion batteries.