Lithium Ion Power Battery Cathode Material LiMn2 O 4 Synthesis And Its Performance Studies

Recently,LiMn₂O₄ is considered to be the most promising new generation as cathode material for lithium ionbatteries,owing to its high voltage,high abundance,low-cost,safety and environmental friendly.However,there are still some problems,such as lower initial capacity,capacity loss during cycling,especially at elevated temperature?55??etc.Those problems are limiting the further marketization of LiMn2O4.In this study,optimization of synthesis process and doping have been adopted to improve the performance of LiMn2O4.The EMD were mixed with Li2CO3 in anhydrous ethanol to synthesize the spinel LiMn2O4 cathode materials by solid state methodassisted with wet ball-milling.The influence of balling time,calcination temperature on the electrochemical performance of LiMn2O4 were investigated systematically.Under the appropriate process steps,the as-prepared LiMn2O4 was modified by Al3+ and?Li+ Al3+?internal doping.The structure,morphology and element content of LiMn2O4 were characterized by XRD,FESEM and ICP.The electrochemical performance was tested by charge-discharge,cycling volt-ampere?CV?and electrochemical impedance spectroscopy?EIS?.The results show that LiMn2O4 materials with different crystallographic size and morphologies can be synthesized via solid state method assisted with wet ball-milling.The 4 hours sample has good crystallinity,spherical morphology and the best electrochemical performance.Calcination temperature has influence in electrochemical performance of LiMn2O4.The LiMn2O4 Calcinated at 800? has the best electrochemical performance.Al³⁺ internal doping can effectively enhance the high temperature?55??electrochemical performance of LiMn2O4.LiMn2O4 doped with Al3+?x=0.1?has the best electrochemical performance.The high-temperature initial discharge capacity is 106.7 mAh·g-1 at 1C?1C=110 mAh g-1?,and still remains 83.7 mAh·g-1 after 100 cycles with the rention of 78.4%.?Li+ Al3+?internal doping can effectively inhiting Jahn-Teller,improving rate performance.LiMn2O4 doped with Al3+?x=0.1?and Li+?y=0.02?has the best rate performance.The discharge capacity is 111.5 mAh·g-1,106.8 mAh·g-1,102.5 mAh g-1,97.6 mAh g-1,94.4 mAh·g-1 and 106 mAh g-1 at 0.5 C?1 C?2 C?4 C?6 C and 0.5C,respectively.