LiFe_(1-x)Mn_xPO_4正极材料的合成及结构与性能

Research on the synthesis, microstructure and performance of LiFe_(1-x)Mn_xPO_4 cathode materials

采用高温固相法、优化操作后合成出LiFe1!xMnxPO4复合正极材料,利用X射线衍射(XRD)分析其结构,扫描电镜(SEM)观察其形貌,恒电流法测定其电化学性能。研究结果表明:合成所得LiFe1!xMnxPO4材料为单一橄榄石型晶体结构,晶型完整、杂相少;对比室温下不同倍率充放电结果发现,LiFe0.8Mn0.2PO4具有较好的电化学性能,在0.5C倍率下首次放电比容量达到134.7mAh/g,循环30次后比容量为127.3mAh/g,循环可逆性能良好。

The lithium ferric manganese phosphate composite cathode materials for lithium-ion battery were prepared by high temperature solid-state reaction in which composite conditions were optimized in order to improve the electrochemical performance of LiFe（1-x）MnxPO4. The crystalline structure, morphology of particles and electrochemical performance of the sample were investigated by X-ray diffraction, scanning electron microscopy and constant current charge-discharge experiments. The results show that LiFe（1-x）MnxPO4 （x=0-0.6） is simple pure olive-type phase with little impurity. LiFe0.8Mn0.2PO4 is found with the best electrochemical properties and good cyclic stability in room temperature, whose first specific discharge capacity is 134.7 mAh/g and still has 127.2 mAh/g after 30 cycles at 1/2 C rate.