锆掺杂以提升LiNi0.5Co0.2Mn0.3O2正极材料的高温电化学性能

Enhanced Electrochemical Performance of LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2 Cathode Materials at Elevated Temperature by Zr Doping

为解决LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2正极材料在高温下循环性能差的问题,本文通过固相法对材料进行锆掺杂改性,研究了不同掺杂量对LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2晶体结构和电化学性能的影响。研究表明,当锆掺杂量为1%(x)时,可以降低LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2结构中的Li+/Ni2+离子混排,有助于材料电化学性能的提高,尤其是高温循环性能。在25°C、3.0-4.3 V下,Li(Ni_(0.5)Co_(0.2_Mn_(0.3)_(0.99)Zr_(0.01)O_2在1C循环95次后容量保持率为92.13%,优于未掺杂样品(87.61%)。在55°C下,Li(Ni_(0.5)Co_(0.2)Mn_(0.3)_(0.99)Zr_(0.01)O_2在1C循环115次后容量保持率仍有82.96%,远高于未掺杂样品(67.63%)。因此,少量锆掺杂对提升LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2的高温循环性能有积极作用。

In order to ameliorate the severe capacity fading of LiNi0.5Co0.2Mn0.3O 2 cathode materials at elevated temperatures, a Zr-doping strategy was performed via a solid-state method, and the influence of the doping content on the structural and electrochemical properties of LiNi0.5Co0.2Mn0.3O2 was studied. The results indicate that the Li^＋/Ni^2＋ cation mixing can be reduced and the electrochemical performance, especially the hightemperature cycling performance, can be improved when the doping content of zirconium is 0.01. After 95 cycles,the capacity retention of Li（Ni0.5Co0.2Mn0.3）0.99Zr0.01O2 is 92.13% at 1C between 3.0 and 4.3 V, which is higher than that of the LiNi0.5Co0.2Mn0.3O2（87.61%）. When cycling at 55 ℃, Li（Ni0.5Co0.2Mn0.3）0.99Zr0.01O2 exhibits a capacity retention of 82.96% after 115 cycles at 1C, while that of the bare sample remains at only 67.63%. Therefore,a small amount of zirconium doping is notably beneficial to the electrochemical performance of LiNi0.5Co0.2Mn0.3O2 at elevated temperatures.