Study On The Solid State Synthesis And Doping Modification Of Lithium Manganate As Anode Material Of Lithium Ion Battery

The anode material which is one of the important components of the lithium ion battery system is the biggest bottlenecks that restrict the popular application of lithium ion battery.It is the key for improving its performance and reducing costs of lithium ion battery.The spinel LiMn₂O₄ is one of the most promising anode materials in the 21th century because of its high working voltage,safty performance,low production cost,and friendly with environment.In this paper,the development of lithium ion battery was summarized,and we analyzed the present research status of lithium ion battery at domestic and abroad. Aimed at the defects such as low theoretical specific capacity and poor electrochemical cycle performance of spinel LiMn₂O₄ anode material,we studied the synthesis technology and doping modification method of spinel LiMn₂O₄ anode material.The spinel LiMn₂O₄ anode material was synthesized by solid state reaction method.We used tap density of powder sample as the experimental inspection target.The effects of the ratio of atom lithium and manganese,reaction temperature and reaction time on structure,microcosmic morphology and electrochemical property of the spinel LiMn₂O₄ anode material were studied though orthogonal regression experimental design methods,and the results showed that the prime craft work conditions to prepare the spinel LiMn₂O₄ anode material are as following:Using LiOH·H₂O and MnO₂(EMD)as raw materials,The temperature of reaction was 750℃,the time of reaction was 24h,and n_Li/n_Mn=1.05:2.The optimize product is the pure spinel phase lithium manganate,the initial discharge specific capacity of the pure spinel LiMn₂O₄ anode material is 118.91 mA·h/g.The discharge specific capacity could still retain about 108.03 mA·h/g after 10 cycles and the specific capacity retention rate is 90.85%.Lithium manganese oxides of Li_1.05M_0.04Mn_1.96O₄(M=Co,Ni) were prepared with Co(CH₃COO)₂·4H₂O·Ni(CH₃COO)₂·4H₂O as dopant.The effects of the doping elements on structure,microcosmic morphology and electrochemical property lithium manganese oxides were investigated,and the results indicated that Li_1.05M_0.04Mn_1.96O₄(M=Co,Ni) exhibited a pure cubic spinel structure,Co and Ni doping could improve the microcosmic morphology of particles,the doped spinel LiMn₂O₄ anode materials exhibit good electrochemical cycle performance,but the initial discharge specific capacity of the doped anode material is lower than the pure spinel LiMn₂O₄ anode material.Co doped LiMn₂O₄ to Li_1.05Co_0.04Mn_1.96O₄ the initial discharge specific capacity is 114.55 mA·h/g.The discharge specific capacity could still retain about 107.71 mA·h/g after 10 cycles and the specific capacity retention is 94.03%.Ni doped LiMn₂O₄ to Li_1.05Ni_0.04Mn_1.96O₄ the initial discharge specific capacity is 113.38 mA·h/g.The discharge specific capacity could still retain about 108.93 mA·h/g after 10 cycles and the specific capacity retention is 96.08%.