Mg、Co共掺对钠离子电池正极材料中阴离子氧化还原过程的改性研究  

Modification of Mg and Co Co-doping on Anion Redox of the Layered Positive Electrode Material for Na-ion Batteries

作　　者：石澎 郭志强 郝一帆 刘校 周飞宇 徐淑银[1] SHI Peng;GUO Zhiqiang;HAO Yifan;LIU Xiao;ZHOU Feiyu;XU Shuyin(School of Physical Science and Technology,Inner Mongolia University,Hohhot 010021,China)

机构地区：[1]内蒙古大学物理科学与技术学院,呼和浩特010021

出　　处：《内蒙古大学学报（自然科学版）》2022年第2期179-186,共8页Journal of Inner Mongolia University：Natural Science Edition

基　　金：内蒙古自治区科技计划项目(2021GG0162);内蒙古自然科学基金项目(2021MS02013);国家自然科学基金(5216020082)。

摘　　要：钠离子电池具有潜在的高能量密度和明显的成本优势,近些年来受到广泛的研究和商业开发。其中,P2型层状氧化物材料因其制备简单、空气稳定性好而被认为是一种很有前景的正极材料,但实际可用可逆比容量较低。Mg掺杂可以触发阴离子氧O_(2)-/(O_(2))^(n-)的氧化还原反应,进而提供可观的容量。但在阴离子氧化还原过程中会产生不可逆相变,使其循环性能变差,并且充放电过程中存在着严重的电压滞后现象。本文采用Mg和Co共掺的手段来调节晶体结构和电子结构,提高比容量的同时,减少电压滞后,提升循环性能。优选得到了正极材料P2-Na_(0.67)Mg_(0.22)Co_(0.22)Mn_(0.56)O_(2),在1.5~4.5V的电压区间内,可逆比容量为198mAh·g^(-1)。相比于同体系的其他材料具有较好的循环稳定性和倍率性能,同时电压滞后现象得到明显改善,为设计新型层状氧化物正极材料提供了新思路。Sodium-ion batteries have been extensively studied for commercialization because of their potential high energy density and obvious cost advantage.P2 layered oxide is considered as a promising choice for cathode owing to its simple preparation and good air stability.However,its applicable specific capacity is low.Mg-doping can trigger anion redox of O^(2)/(O_(2))^(n-)and afford extra capacity.However,irreversible phase transitions occurred to result in worse cycle performance and serious voltage hysteresis.The strategy of Mg and Co co-doping is used to adjust the crystal and electronic structure,improve the electrochemical performance,and reduce the voltage hysteresis.Preferably,the positive electrode material P2-Na_(0.67)Mg_(0.22)Co_(0.22)Mn_(0.56)O_(2)is obtained,and the reversible capacity is 198 mAh·g^(-1)in the voltage range of 1.5~4.5 V.Compared with other materials in the same system,it shows higher cycle and rate performance,lower voltage hysteresis which can be attributed to enhanced kinetic performance after Co doping.These results provide a new idea for the design of new layered cathode materials.

关 键 词：钠离子电池 正极材料 阴离子氧化还原 电压滞后 Mg掺杂 Mg、Co共掺杂 

分 类 号：TM912[电气工程—电力电子与电力传动]