橄榄石LiFePO4复合正极材料的合成及其电化学性能研究

采用固相反应法在惰性气氛中合成了橄榄石型LiFePO₄/C复合正极材料,考察了焙烧温度对目标材料性能的影响.采用XRD、SEM、TG-DSC、激光粒度分布以及电化学测试等手段对该材料进行了结构表征和性能测试.结果表明,完美的结晶、较小的粒径以及与导电剂的良好接触是产物具有优良电化学性能的保证.于750℃下制得产物的结构完整,表面形貌较好,粒经分布均匀,具有良好的电化学性能.在室温及0.05 C充放电倍率下,该材料的首次放电容量为142.5 mA.h/g,循环50次后,未见明显衰减.

Synthesis and Electrochemical Performance of Olivine LiFePO 4-based Composite Cathode Materials

Olivine LiFePO₄/C composite cathode materials were synthesized by a solid state method in an inert atmosphere.The effects of the calcined temperature on the properties of as-synthesized cathode materials were investigated.The crystal structure and the electrochemical performance were characterized by XRD,SEM,TG-DSC,laser particle-size distribution measurement and electrochemical performance testing.The results demonstrate that pure and well-crystallized powders,smaller particle size and intimate carbon contact are necessary for optimizing electrochemical performance.The material calcined at 750 ℃ had a complete olivine structure,uniform surface morphology,better particle-size distribution and excellent electrochemical performances.The initial discharge capacity,namely 142.5 mA·h/g,was obtained at room temperature and 0.05 C charge-dischange rate.After 50 cycles,there was no obvious capacity fade.