Solid Phase Synthesis Of Nickel-based Lithium Ion Battery Cathode Material

Ni-rich layered cathode materials have been attracted more attention due to it's high specific capacity,stable cycle performance and a better safety performance.In this paper,In the present work high temperature soild state synthesis method wad used to prepare LiNi_0.5Co_0.2Mn_0.3O_2,LiNi_0.6Co_0.2Mn_0.2O_2,LiNi_0.8Co_0.1Mn_0.1O₂?called 523,622,811?.Element-doping was also investigated.This thesis mainly work as follows.LiNi_0.5Co_0.2Mn_0.3O₂,LiNi_0.6Co_0.2Mn_0.2O₂ and LiNi_0.8Co_0.1Mn_0.1O₂ was synthesized by sintering the mixture of as-prepared precursor and Li₂CO₃ Or Li OH·H₂O.Their structural and electrochemical properties were investigated.1?LiNi_0.5Co_0.2Mn_0.3O₂ cathode material synthesized by Li₂CO₃ sintered at 800 ⁰C delivered an initial discharge capacity of 155.4 mAh·g^-1 at 0.1 C rate between 3 and 4.3 V and more than 98.8%of that was retained after 100 cycles.LiNi_0.6Co_0.2Mn_0.2O₂ cathode material synthesized by Li₂CO₃ sintered at 700 ⁰C delivered an initial discharge capacity of180.9 mAh·g^-1 at 0.1 C rate between 3 and 4.3 V and more than 98.6%of that was retained after 100 cycles.We tested a part of Li Ni_0.5Co_0.2Mn_0.3O₂ sample under 3⁴.5V.It synthesized by Li₂CO₃ sintered at 700 ^oC delivered an initial discharge capacity of 154mAh·g^-1at 0.1 C rate between 3 and 4.5 V and more than 90.9%of that was retained after100 cycles.2?LiNi_0.5Co_0.2Mn_0.3O₂ cathode material synthesized by LiOH·H₂O sintered at 800^oC delivered an initial discharge capacity of 165.9 mAh·g^-1at 0.1 C rate between 3 and 4.3 V and more than 88.8%of that was retained after 100 cycles.LiNi_0.6Co_0.2Mn_0.2O₂ cathode material synthesized by LiOH·H₂O sintered at 800 ^oC delivered an initial discharge capacity of 172 mAh·g^-1 at 0.1 C rate between 3 and 4.3 V and more than 92.7%of that was retained after 100 cycles.LiNi_0.8Co_0.1Mn_0.1O₂ cathode material synthesized by LiOH·H₂O sintered at 800 ^oC delivered an initial discharge capacity of 184.3 mAh·g^-1 at0.1 C rate between 3 and 4.3 V and more than 75.1%of that was retained after 100 cycles.3?Because of the lithium loss,We usually provide excess lithium to reduce the synthesis of loss.This paper synthesized Li _XNi_0.5Co_0.2Mn_0.3O₂,Li _XNi_0.6Co_0.2Mn_0.2O₂,Li_XNi_0.8Co_0.1Mn_0.1O₂?X=1.00,1.02,1.00,1.02,1.08 and 1.10?to study the overdose of lithium.The results showed that the battery performance is good when the lithium salt excess 2%⁴%,and too low or too high lithium salt content can make the battery performance decline.4?We make lithium carbonate as lithium source to synthesis LiNi_0.6Co_0.2Mn_0.2O₂samples doping La?Ce?Ti?Zr and Cr?molar ratio was 1:0.05?.After doping discharge capacity has a certain decline for the first time.The Ti-doping is effective in improving its comprehensive electrochemical performance,when lithium carbonate was used as the Li-source.The initial discharge capacity is 154.1 mAh/g,after 100 cycles it is 148 mAh/g more than 96%of that was retained and after 500 cycles it is 100.5 mAh/g more than65.2%of that was retained.