Synthesis Of Lithium-ion Battery Cathode Material LiFePO₄ And LiMn₂O₄ By Comprehensive Utilization Of Potassium Permanganate Residue

With the growing shortage of global energy and resources,the development of new energy and comprehensive utilization of mineral resources have become the focus of worldwide attention.In this paper,we propose a new idea to synthesize lithium-ion battery cathode material LiFePO4 and LiMn2O4 from potassium permanganate residue.Meanwhile,the physical and chemical processes and theories of the potassium permanganate residue hydrometallurgy and materials preparation are studied.The elements of potassium permanganate residue are selectively leached by sulfuric acid and leaching at atmospheric pressure.Under the optimum conditions,the elements such as calcium and silicon are left in the filter residue,almost no leaching;valuable elements are enriched in lixivium,Iron leaching rate of 40%or more,manganese leaching rate of 90%or more.Under the conditions of reaction temperature 95℃,pH=2.5 and reaction time 10 h,79.8%Fe was converted to ammonium jarosite.Mn was separated from the filtrate in the form of Mn3O4,the stirring time was 1 h,and the removal rate of manganese was up to 97.47%at the reaction temperature of 60℃,and the effective separation of the valuable elements in the filtrate was realized.The LiFePO4/C was prepared by using ammonium jarosite as the iron source,Li2CO3 as the lithium source,organic saccharide as the carbon source and NH4H2PO4 as the phosphorus source.A well-crystallized,single olivine structure of lithium iron phosphate was obtained.The effects of different carbon sources and carbon contents on the electrochemical performance of Li-ion batteries were investigated.It was found that the addition of C was glucose and the mole ratio of C to ammonium jarosite was 1.3:1,the electrochemical performance of the battery was optimized.The first discharge specific capacity can reach 145 mAh/g at 0.1 C.The LiMn2O4 cathode material was prepared by calcination of Mn3O4 as the manganese source and Li2CO3 as the lithium source.The orthogonal experiment was carried out to determine the optimal roasting process:the ratio of lithium to manganese was 1.08:2,the calcination temperature was 800℃ and the calcination time was 8 h.The initial discharge specific capacity of lithium manganate prepared at this condition was 113 mAh/g at 0.1 C rate.The method can separate the valuable elements in the waste residue of potassium permanganate and prepare the energy storage material with high added value,which provides a new way for the waste residue produced by the potassium permanganate production enterprise.