二次煅烧制备LiFePO4/C正极材料及其性能研究

通过高温固相还原FePO4.2 H2O的方法制备橄榄石结构的LiFePO4正极材料,分别采用蔗糖和Fe粉为还原剂,在二次煅烧的工艺下考察不同温度及煅烧时间等因素对材料电化学性能的影响,得出最佳工艺组合。结果表明Fe粉为还原剂性能优越,在700℃煅烧8 h得到的样品最佳,X射线衍射光谱法(XRD)和扫描探针显微镜(SEM)的测试也显示在该工艺下合成样品具有较好的晶体结构。同时两种方法合成的样品在0.05 C时的最大放电比容量分别达到152 mAh/g和156 mAh/g,且具有良好的循环稳定性。

Synthesis of LiFePO4/carbon cathode material by two-stage calcination method

LiFePO4/carbon cathode material with ordered olivine structure was synthesized from amorphous FePO4· 2H2O through a solid phase using sucrose and Fe as the reducing agent.The effects of factors such as synthesis temperature and time on the electrochemical performance ofLiFePO4/C were systematically investigated to optimize the synthesis techniques with the two-stage calcination.The results indicate that the best sample is synthesized at 700 ℃ for 8 h using ball-milling with water,and XRD and SEM observations show that this sample composite has good crystallinity.The samples synthesized by these two ways shows a high discharge specific capacity of 152 mAh/g and156 mAh/g at rates of 0.05 C,and exhibits an excellent cycling performance.