废旧磷酸铁锂的高效回收再利用

Efficient recycle and reuse of spent lithium iron phosphate

将磷酸铁锂(LiFePO_(4))回收料煅烧除杂,再用柠檬酸溶液预处理,补加磷酸铁(FePO_(4))等原料,引导合成反应,恢复性能。用XRD、SEM和恒流充放电测试,对材料进行分析。将LiFePO_(4)回收料在空气中、450℃下煅烧除杂,得到除碳料;用5g 1.4%柠檬酸溶液松解500 g除碳料晶粒;再按m(除碳料)∶m(FePO_(4))=4∶1补加磷酸铁,搅拌、研磨并干燥;在氮气保护下、770℃保温10 h,制得LiFePO_(4)。样品在2.0~4.2V循环,0.2C、1.0C首次放电比容量分别为159.86 mAh/g、150.06 mAh/g。

The recycled material of lithium iron phosphate(LiFePO_(4))was calcined to remove impurities,then pretreated with citric acid solution.The raw materials such as iron phosphate(FePO_(4))were added to guide the synthesis reaction and restore the performance.XRD,SEM and galvanostatic charge-discharge tests were used to analyze the samples.The carbon removal grains were obtained by calcining the recycled LiFePO_(4) at 450℃in air.500 g carbon removal grains were released by 5 g 1.4%citric acid solution,then iron phosphate was added according to m(carbon removal grains)∶m(FePO_(4))=4∶1 to carbon removal grains,then stirred,ground and dried.LiFePO_(4) was finally prepared by keeping temperature at 770℃for 10 h under the protection of nitrogen.When charged-discharged in 2.0-4.2 V,the initial discharge specific capacities of the sample at 0.2 C and 1.0 C were 159.86 mAh/g and 150.06 mAh/g,respectively.