【摘要】 通过溶胶-凝胶法并结合热处理工艺制备LiFePO4粉体,采用XRD、SEM及恒电流充放电技术等方法,研究了煅烧时间对LiFePO4粉体结构、形貌及电化学性能的影响。结果表明:以聚丙烯酸(PAA)、硝酸铁、硝酸锂和磷酸二氢铵为原料,在一定温度下合成了稳定的溶胶和凝胶,经650℃煅烧得到LiFePO4粉体。随着煅烧时间的延长,粉体颗粒逐渐增大,晶型趋于完整;煅烧16 h获得的LiFePO4颗粒大小均匀,晶型完整且没有明显团聚现象。1C倍率下首次放比电容量达到140 mAh/g,经100次循环后仍高于130 mAh/g,容量保持率高达93%,表现出良好的充放电稳定性。更多还原

【Abstract】 LiFePO4 powder was synthesized by sol-gel and heating treatment process.The influences of sintering time on the microstructure,morphology and electrochemical performance were explored by XRD,SEM and galvanostatic charge-discharge.The results show that the stable sol and gel were prepared by PAA,FeNO3,LiNO3 and NH4H2PO4 in water solution.The LiFePO4 can be obtained under sintering at 650 ℃.With the increase of calcination time,LiFePO4 particle becomes larger and the crystal structure is more integrity.The LiFePO4 powder prepared by heating treatment gel at 650 ℃ for 16 h exhibits uniform distribution,high crystallinity,low agglomeration and high electrochemistry performance.The first discharge capacity reaches 140 mAh/g at the rate of 1C,and the capacity remains 130 mAh/g after 100 cycles.The capacity retention ratio reaches 93%,which can prove that LiFePO4 has stable cycle performance.更多还原