磷酸铁锂烧结工艺对磷化铁生成的影响

Effects of lithium iron phosphate calcination condition to formation of iron phosphorus

通过XRD分析,研究预烧、煅烧环境对制备磷酸铁锂（LiFePO4）时磷化铁（Fe2P）杂质的影响。预烧中生成大量的还原性气体及煅烧温度,对Fe2P的生成有重要影响。在预烧和煅烧过程中,对LiFePO4的深度还原是Fe2P形成的唯一原因。含有Fe2P的LiFePO4的动力学特性更高。4 kg/批下制备的LiFePO4前驱体在箱式炉中预烧,再在管式炉中800℃下煅烧20 h,产物在2.0--4.2 V循环,0.1 C首次放电比容量为152 m Ah/g,2.0 C放电比容量可达133 m Ah/g。

XRD analysis was used to investigate the effects of pre-heating and calcination conditions to iron phosphoms（Fe2P） impurity when preparing lithium iron phosphate （ LiFePO4 ）. The large quantities of reduetive gas and the calcination temperature had great effects to the form of Fe2 P. Further reducing of LiFePO, in pre-heating and calcination process was the only reason for the formation of Fe2P. The LiFePO4 which contained Fe2p had higher kinetic characteristics, when LiFePO4 precursor prepared in 4 kg/batch was pre-heated in box furnace then calcinated at 800 ℃ for 20 h, the 0. 1 C initial specific discharge capacity was 152 mAh/g when the product was cycled in 2.0 -4.2 V, the 2.0 C specific discharge capacity could reach to 133 mAh/g.