Preparation Of LiMn₂O₄ Cathode Material By Homogeneous Method And The Doping Modification Studies

With the rapid development of cutting-edge technology,people’s demand for mobile energy storage devices has gradually increased.Today,energy shortage and environmental protection are gradually being paid attention to.Lithium-ion batteries are attractive for using in the field of mobile power source with the favorable properties of high energy density,long cycle life,easy to produce industrially and no memory effect.Cathode material of lithium-ion batteries is the main component of lithium-ion batteries,occupying the main cost and main content.The properties of cathode materials will directly affect the indexes of lithium-ion batteries.Cathode materials occupy a core position in lithium-ion batteries.The spinel manganic acid lithium（LiMn₂O₄）has been considered to be a promising cathode material because of its high voltage,good safety,abundant raw materials,non-toxicity and environmentally friendly.However,the practical application is limited by capacity fading and bad rate performance.To improve the discharge capability,researches have conducted a lot of research,bulk doping and changing particle size are effective approaches to improve the electrochemical performance of LiMn₂O₄materials.In this study,LiMn₂O₄ materials were prepared via homogeneously precipitation method.The influence of the amount of urea,the amount of urease,calcination time and bulk doping on morphology,structure and electrochemical properties of LiMn₂O₄materials were investigated,and obtained superior process for the preparation of LiMn₂O₄by homogeneously precipitation method.LiMn₂O₄ was prepared by homogeneous precipitation and co-precipitation,respectively,compared with the co-precipitation method,the performance of synthesized by homogeneously precipitation method was much better.The initial discharge capacities of LiMn₂O₄ prepared by homogeneously precipitation method were 108.36 m Ah·g^-1at0.5C-rate.The LiMn₂O₄ prepared by homogeneously precipitation method was doped with Mo⁶⁺,the changes of electrochemical properties under different doping levels were discussed.The results showed that when the Mo⁶⁺doping amount was 0.03 with good rate capacity,the doped material discharge capacities were 43 m Ah·g^-1 at 5C（2 times of raw LiMn₂O₄ material）.The LiMn₂O₄ prepared by homogeneously precipitation method was doped with La³⁺,the changes of electrochemical properties under different doping levels were discussed.The results show that LiMn₂O₄ with a doped amount of 0.03 has high cycling performance,The specific capacity of the first discharge reached 113.4 m Ah·g^-1 at 0.5 C,and the capacity retention rate was 84.7%after 50 cycles.