Preparation And Modification Of LiNi_0.6Co_0.2Mn_0.2O₂ Ternary Cathode Material

The high energy density of the lithium ion battery allows it to release more energy in the same volume,which plays a key role in its application in electronic products and other devices.The LiNi_xCo_yMn_zO₂ ternary material has good cycle performance,resulting in a slow capacity decay,and a long life during cycling.Meanwhile,ternary cathode material can also work in a high-pressure environment and a wide temperature range.All these advantages make people full of expectation for its commercial application.This article mainly focuses on the effects of precursor preparation,calcining conditions,additive and coating modification material performance,and the realization of LiNi_0.6Co_0.2Mn_0.2O₂cathode material with excellent comprehensive performance.The contents are as follows:The precursor is prepared by using three different preparation methods:Na₂CO₃ as precipitant,NaOH as precipitant,and sol-gel method.Then the precursor is mixed with lithium carbonate at a certain ratio and ground.The mixtures are heated up to 500? for 5h,and then heated up to 850? for 15h.Finally,a cathode electrode material sample was obtained.Based on the XRD and SEM patterns of the three samples and their corresponding precursors,it can be concluded that all the three methods can produce a highly crystalline material structure.By comparing the first charge and discharge curve,the cycle rate performance,and the cyclic voltammetry and electrochemical resistance impedance analysis,the results show that the discharge capacity and capacity retention rate of the samples obtained by Na₂CO₃precipitation are relatively high.Based on the preparation of precursors by Na₂CO₃ precipitation,the calcining temperature was studied.From the structure,morphology,electrochemical test and other results,it was found that the obtained cathode material under the calcining conditions of holding at 500? for 5h and holding at 850? for 15h.has stable structure,complete morphology,specific discharge capacity of189.7m Ah/g,Coulomb efficiency of 97.96%,and high capacity retention rate.It is the best calcining condition for preparing LiNi_0.6Co_0.2Mn_0.2O₂ material.Subsequently added with ZrO₂ and GO,the structure stability and conductivity of the material can be improved,resulting in a great enhancement of the reversibility of its redox reaction,and an improvement of the material's cycle performance.In order to further enhance the high-rate cycle stability of the material,the SiO₂ and rGO protective films are coated on the surface of the material to suppress the adverse reaction between the cathode electrode material and the electrolyte.The experimental results also prove that this method is successful.The cycle performance of LiNi_0.6Co_0.2Mn_0.2O₂@Si O₂@r GO has been greatly improved both at 0.5C and 1C rates.The capacity at high rates decays slowly within 100 cycles and the cycle life is long.