Study On The Preparation And Energy Storage Characteristics Of Ternary Cathode Materials For Lithium Batteries

The rapid economic development has also led to the exhaustion of traditional energy sources and the aggravation of environmental pollution.People urgently need to develop renewable clean energy.This led to the rapid development of lithium-ion batteries.However,traditional cathode materials such as lithium cobalt oxide,lithium manganate are difficult to meet the requirements of power batteries.Therefore,we need to find a cathode with high specific capacity,low cost,and better safety material.The ternary cathode material lithium nickel cobalt manganese oxide has become our research hotspot due to its ultra-high specific capacity.However,some shortcomings of ternary lithium nickel cobalt manganese oxide itself limit its commercial application,such as poor cycle stability and high current discharge capability.Therefore,improving its cycle stability and high-current charging and discharging capabilities has become the main research content of this article.（1）The rod-shaped cobalt-manganese metal oxide precursor was successfully synthesized by the oxalic acid co-precipitation method,and then the ternary lithium nickel cobalt manganese oxide(LiNi_0.6Co_0.2Mn_0.2O₂)was obtained after high-temperature sintering with a lithium nickel source through ball milling.The effect of different sintering temperatures on the electrochemical properties of the material was systematically studied.The experimental results show that the sample sintered at a high temperature of 850℃ has the best electrochemical performance.The sample sintered at a high temperature of850℃ has the highest initial discharge specific capacity of 149.2 mAh/g at 0.5 C.After200 cycles of charge and discharge After cycling,its discharge specific capacity is still134.5 mAh/g,and the capacity retention rate is 90.1%.（2）On the basis of the previous experiment,Al³⁺was introduced when synthesizing the rod-shaped cobalt-manganese metal oxide precursor.After high-temperature sintering with a lithium nickel source by ball milling,the Al-doped ternary lithium nickel cobalt manganese oxide was successfully synthesized lithium.The influence of different Al doping levels on the electrochemical performance of ternary lithium nickel cobalt manganese oxide was explored.The experimental results show that Al doping not only retains the good cycle stability before undoping,but also greatly improves the initial discharge capacity and better high-current charge and discharge capabilities.When the Al doping amount is 1%,the best electrochemical performance is shown.At 0.5 C,the initial discharge specific capacity of the material is 157.6 mAh/g,and the discharge specific capacity of the material after 100 cycles is 153.3 mAh/g.The electrochemical performance under a long cycle of 200 cycles was explored.After 200 cycles,the specific discharge capacity of the material was 148.9 mAh/g,which retained 94.5%of the initial specific discharge capacity,and had good cycle stability.The discharge specific capacity of the material at 3 C is 143 mAh/g,which is an increase of 14.9 mAh/g compared to the capacity before doping.（3）Similar to Experiment 2,Ce⁴⁺was introduced into the rod-shaped cobalt-manganese metal oxide precursor,and the Ce-doped ternary lithium nickel cobalt manganese oxide was successfully synthesized after high-temperature sintering with a ball-milled mixed lithium-nickel source.The influence of different Ce doping amount on the electrochemical performance of ternary lithium nickel cobalt manganese oxide was explored.The experimental results show that as the amount of doping increases,the electrochemical performance of the material first becomes better and then becomes worse,with the best electrochemical performance when doped at 2%.Under 0.2 C,0.5 C,1 C,2C,3 C,the specific discharge capacity of the material is 161.8 mAh/g,155.4 mAh/g,149.8 mAh/g,141 mAh/g,134.5 mAh/g,and when the current density returns 0.2 C,the discharge capacity of the material is 160.4 mAh/g,which has good reversibility.