摘要
Abstract
A doping-coating surface modification method was used to improve the cycle performance of the lithium-ion battery cathode material spinel LiMn2O4. Al was chosen as the doping element and AI(NO3)3 as the raw material. We investigated Al3* doping of 7.1%(atomic fraction) at the temperatures of 300,400, 500, 600, 700, 750, and 800 ℃. It was found that at increasing temperatures, the maximum specific capacity of the modified samples first increased and then decreased, with a maximum at 700 ℃. The fading rate increased initially with temperature as well, and then decreased, followed by a small rise with temperature. This is because the coated layer gradually reacted with the LiMnzO4 granule at elevated temperatures and became a completely solid solution layer by 750 ℃. The fading rate reached the minimum at the same time. Subsequently, the solid solution layer diffused into the LiMn2O4 granule, weakening the granule protection so that the fading rate slightly increased. Among these samples, the maximum specific capacity (133.6 mAh ·g-1) was for the sample treated at 700 ℃ for 5 h, and the fading rate was 3.4% after 50 cycles. It is shown that doping-coating surface modification with Al3+ may enable the commercial application of spinel LiMn2O4 cathode material for lithium-ion batteries.关键词
锂离子电池/正极材料/尖晶石型LiMn2O4/表面掺杂包覆改性/固溶体Key words
Lithium-ion battery/ Cathode material/ Spinel LiMn2O4/, Doping-coating surface modification/ Solid solution分类
化学化工
