The Investigation Of Preparation The Electrode Material Spinel LiMn₂O₄ And Doping Modification With Nickel And Cobalt

Rechargeable lithium ion batteries have attracted worldwide attention because its high energy invert efficiency, good to environment, easy to carry and convenient for using. The resource of Mn is abundance, cheap and has no contaminated to the environment. The intentions of this work mainly focus on using the research of preparation technics, compose condition to look for the advanced anode material which can convenient to compose, has great cycle capacity and discharge specific capacities.LiMn₂O₄ was synthesized in air atmosphere via by rheological phase reaction method and subsection calcined method in optimizing technology conditions. Meanwhile, the two kinds of elememt doped materials were also conducted on the basis of LiMn₂O₄ material. Use Thermogravimetry (TG) to confirm the temperature of calcine, X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) to observe structure and superficial morphology, Galvanostatic charge-discharge test to study electrochemical properties.The result show that the optimize product is spinel phase lithium manganate the first discharge specific capacities of the LiMn₂O₄ is 114.30mAh·g^-1. The discharge specific capacities could still retain about 105.10mAh·g^-1 after 50 cycles and the specific capacity retention is 92.0%. Ni doped LiMn₂O₄ to LiNi_0.05Mn_1.95O₄ the first discharge specific capacities is 108.82mAh·g^-1. The discharge specific capacities could still retain about 107.94mAh·g^-1, after 50 cycles and the specific capacity retention is 99.2%. Co doped LiMn₂O₄ to LiCo_0.15Mn_1.85O₄ the first discharge specific capacities is 110.31mAh·g^-1. The discharge specific capacities could still retain about 107.03mAh·g^-1, after 50 cycles and the specific capacity retention is 97.0%. The cycle performance of the material is improved obviously, has smooth surface, no edges and corners, the particles size is well distribution, has great superficial morphology and electrochemical properties. Combine the conclusion of structure and performance analysis with element Co and Ni, to Analyze the influence of them in crystal field stabilization energy, hydronium semidiameter, crystal lattice energy and oxidation value.