层状正极材料LiMnO_2制备及电化学性能研究

Study on the synthesis of layered cathodic material LiMnO_2 and its electrochemical performance

利用水热混合碱法制备出了一种结构较稳定的层状正交LiMnO2,并对其电化学性能、晶型进行了研究。结果表明该方法制备出的正极材料结构属于O3式碱青铜结构,其晶格参数分别为a=0.2808nm,b=0.5748nm,c=0.456nm,与标准数值相差很少。充放电曲线表明开始时容量下降很快,而后下降就趋于平缓,容量几乎为恒定值,同时XRD显示材料在充放电过程中存在着结构的转变,经过充放电后材料中出现了杂质,材料的比容量在前15次循环中比容量下降了24mAh·g-1(占初始放电比容量的17.1%)。

An orthorhombic layered lithium manganese oxide was synthesized by mixed-alkaline hydrothermal reaction, and its electrochemical performance and crystal structure were studied. Results show that the products belong to O3 bronze structure, the lattice parameters are a=0.280 8 nm, b=0.574 8 nm, c=0.456 nm. Charge-discharge curves described that specific capacity fade was quick at the beginning, and then it became slow. After 15 cycles its specific capacity only dropped24 mAh·g-1(17.1% of the initial discharge specific capacity ).