溶胶-凝胶法合成3LiMnPO4·Li3V2(PO4)3及其电化学性能研究

Synthesis and Electrochemical Performance of 3LiMnPO_4·Li_3V_2(PO_4)_3 by Sol-Gel Method

以柠檬酸为络合剂,聚乙二醇(PEG)为表面活性剂,偏钒酸铵、乙酸锰、磷酸二氢铵、氢氧化锂为原料,采用溶胶-凝胶法合成了xLiMnPO4·y Li3V2(PO4)3锂离子电池复合正极材料。采用X射线衍射(XRD)、扫描电镜(SEM)对其晶体结构和微观形貌进行表征,结果表明在700℃下烧结15 h合成的3LiMnPO4·Li3V2(PO4)3为结晶良好的两相结构,颗粒粒径相对较小且分布均匀。电化学性能研究表明,3LiMnPO4·Li3V2(PO4)3在室温0.2 C倍率下首次充放电容量分别为148.2 m Ah/g和141.5 m Ah/g,循环50次后放电容量为136.7 m Ah/g。

xLiMnPO4· yLi3V2（PO4）3composite as a cathode material for lithium ion batteries was synthesised via a sol-gel method using citric acid as chelating agent,PEG as surface active agent and ammonium vanadate,manganous acetate,ammonium dihydrogen phosphate,lithium hydroxide as raw materials. Crystalline structure and morphology of the composite were characterized by X-ray diffraction（XRD）,scanning electron microscope（SEM）. The results indicate that the 3LiMnPO4·Li3V2（PO4）3composite Is well crystallized as a two-phase structure at annealing temperature of 700 ℃ for 15 h. The3 LiMnPO4·Li3V2（PO4）3microparticles have relatively small particle sizes with uniform distribution.The initial charge and discharge capacity of 3LiMnPO4·Li3V2（PO4）3are 148. 2 m Ah /g and 141. 5m Ah /g at rates of 0. 2 C under room temperature,respectively. After 50 cycles,the discharge capacity still remains 136. 7 m Ah /g.