Doping Modification Of Lithium Manganate And Process Design Of Lithium Ion Battery

In order to improve the cycle and high rate performance of spinel LiMn₂O₄, the synthesis and modification of LiMn₂O₄ were studied by using various electrochemical methods in combination with modern analytic techniques, such as XRD, SEM and so on. At the same time, in order to deeply study LiMn₂O₄ and perfect the evaluation system of LiMn₂O₄, the manufacturing technology of the power batteries were studied by using various electrochemical methods in combination with safety performance test and so on.The material of LiMn₂O₄ was synthesized by high temperature solid state method. The effects of synthesis conditions on the performances of LiMn₂O₄ were studied. The results show that the sample of LiMn₂O₄ with Li/Mn=1.15:2 prepared under 750℃ for 12-20 hours has both the good electrochemical performance and high tap density.The spinel LiMn₂O₄ is modified by the ion F- doped. The effect of the different amounts of F" on the performances of LiMnO4-xFx was investigated. The results show that LiMn2O3.94F0.06 delivers the best electrochemical performances. The initial discharge specific capacity of LiMn2O3.94F0.0e is 109.0 mAh/g at 0.1C rate. As at the 1C rate, the discharge specific capacity of LiMn203.94F0.06 is 104.4mAh/g, and the capacity retention is 98.18% after 40 cycles. To the best of our knowledge, we modify the spinel LiMn₂O₄ by co-dopedof Al3+ and La3+ firstly. The effect of the different amounts of Al3+ and La3+ on the performances of LiAlx1Lax2Mn2-x1-x2O4 was investigated. The results show that LiAl0.02La0.02Mn1.96O4 displays the best electrochemical performances. Its initial discharge specific capacity is 102.3mAh/g at 0.1C rate And its discharge capacity at 0.2C,1C,2C and 5C rate is 99.2%,96.3%,94.8% and 87.8% of that at 0.1C rate,respectively. Finally its cycling performance is good.The 183665AR Li-ion power batteries were used by the commercial LiMn₂O₄ as cathode material. We has investigated the effect of different raw materials, different cathodes’surface density, different compaction density, different contents of conductive agent and different weight ratio between cathode and anode material on the battery electrochemical performances. The results showed that the battery consisted of LiMn₂O₄ （produced by Manufacturer B） as cathode material and AGP-3 as anode material has the best comprehensive performance with the cathode surface density of 3.3g·dm-2, the cathode compaction density of 2.8g·cm-3, the cathode conductive agent content of 5% and the cathode material’s weight of 1:1.05 to that of anode material.