Mg-Y共掺杂高电压钴酸锂正极材料的合成及其性能研究

The synthesis of Mg-Y doped Cobalt Oxide cathode material and the studies on its performance in high voltage

摘要:

将Co₃O₄、Li₂CO₃、Mg(OH)₂和Y₂O₃按一定化学计量比称取并混合均匀后,采用高温固相法合成LiCo_1-x-yMg_xY_yO₂正极材料并探究了Mg-Y共掺杂对钴酸锂高电压性能的影响。采用X射线衍射(XRD)和扫描电镜(SEM)分别表征其晶体结构和形貌。LiCo_1-x-yMg_xY_yO₂正极材料高电压性能测试,结果表明选择Mg掺杂量为0.2wt%下,当Y掺杂量的质量百分数为0.10%wt时,在3.0-4.6V电压范围内0.5C下的初始放电比容量为212.3mAh/g,循环50圈的容量保持率为96.28%。4C大倍率下,未掺杂Y元素样品容量保持率为54.92%,相比之下Y掺杂后容量保持率提高为60.43%。

关键词:锂离子电池;正极材料;钴酸锂;掺杂改性

Abstract:

In order to improve the lifetime of the Lithium-ion battery, Mg-Y co-doped LiCoO2 was prepared by high temperature solid phase synthesis, with Co3O4, Li2CO3, Mg(OH)2 and Y2O3 as raw materials. The structure and morphology were characterized by X-ray diffraction (XRD) and scanning electron microscpoe (SEM). The battery achieved best electrochemical performance when the cathode is doped with 0.10wt% yttrium and 0.20wt% magnesium. The results of electrochemical performance showed that the initial discharge capacity was 212.3 mAh/g at 0.5C, 3.0-4.6V and with the outstanding capacity retention of 96.28% after 50 cycles at 3.0-4.6V. The discharge capacity of co-doped LiCoO2 at 4.0C remained 60.43% of the discharge capacity at 0.2C, while that of Mg only doped LiCoO2 is only 54.92%.

Key words:lithium-ion battery; cathode material; LiCoO₂; doped