钴钛共掺杂对LiNiO2正极材料电化学性能的影响

本文采用溶胶-凝胶法制备了钴和钛共掺杂的层状LiNi_0.82Co_0.15Ti_0.03O₂正极材料,研究了离子掺杂对LiNiO₂材料电化学性能的影响。XRD和XPS分析显示,钴和钛共掺杂可以抑制Li+和Ni2+离子在Li层的混排现象。电化学测试结果表明,钴单元素掺杂可以显著提高LiNiO₂材料的倍率性能,而钛单掺杂则提高了材料的循环稳定性。进一步地,通过钴钛共掺杂的协同作用,可以使LiNiO₂材料的倍率性能和循环稳定性同时得到极大的提高。在200 mA/g的电流密度下循环200次,LiNi_0.82Co_0.15Ti_0.03O₂材料的容量保持率高达94.4%,而未掺杂的LiNiO₂材料容量保持率仅为57.1%;且在1000 mA/g的电流密度下,放电比容量仍能维持在100 mAh/g左右。

Effect of Co/Ti co-doping on electrochemical performance of LiNiO2cathode materials

In this paper,we have synthesized Co-Ti co-doped layered LiNi_0.82Co_0.15Ti_0.03O₂ cathode material by a sol-gel method.The effects of the element-doping on the structure and electrochemical properties of the layered LiNiO₂cathode material were studied.XRD and XPS analyses showed that the cation mixing of Li⁺and Ni²⁺ions in the Li layer in the LiNiO₂crystal lattice can be effectively suppressed by a Co-Ti co-doping.By measuring the electrochemical properties of different as-synthesized LiNiO₂based materials,it is found that the rate performance of LiNiO₂cathode materials can be significantly improved by single element Co-doping,while the cycle stability of LiNiO₂cathode materials can be enhanced by single element Ti-doping.Furthermore,the rate capability and cycle stability of LiNiO₂were improved through the synergistic effect of Co-Ti co-doping.The capacity retention of LiNi_0.82Co_0.15Ti_0.03O₂ cathode material was still as high as 94.4%after 200 cycles at the current density of 200 mA/g,while the capacity retention of undoped LiNiO₂material was only 57.1%.At the same time,the discharge capacity of Co and Ti co-doped LiNiO₂cathode materials can still be maintained at 100 mAh/g under the current density of 1000 mA/g.