摘要
研究钠离子电池(SIBs)对开发新能源和新储能方式具有重要意义。P2型层状氧化物Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2)正极材料具有容量和工作电压较高的优点,但在高电压下发生的P2-O2不可逆相变会导致体积急剧变化,容量迅速衰减。针对这个问题,本研究采用Cu和Mg协同取代的策略,通过固相反应法合成了P2-Na_(0.67)Ni_(0.18)Cu_(0.10)Mg_(0.05)Mn_(0.67)O_(2)(NCMM-10-05)正极材料。结果表明,掺入Cu和Mg有效抑制了P2-O2相变,转而形成了可逆程度更高的OP4相,提高了材料结构的可逆稳定性,且电化学性能得到了显著提升。在2.00~4.35 V(vs.Na^(+)/Na)电压窗口内NCMM-10-05初始放电容量为113mAh·g^(-1),在8C(1C=100 mA·g^(-1))电流密度下仍有64.1 mAh·g^(-1)的可逆容量,在1C电流密度下循环200圈后容量保持率可以达到88.9%。本研究探讨了Cu和Mg协同取代对P2型层状氧化物结构与电化学性能的影响,并通过原位X射线衍射(XRD)分析与密度泛函理论(DFT)计算进一步探究了Cu、Mg元素在结构演变中的具体作用,为合理设计具备Na+快速传输能力和高稳定性的SIBs正极材料提供了参考。
The research of sodium-ion batteries(SIBs)is of great significance for development of new energy and energy storage methods.As cathode material,P2-type layered oxide material Na_(2/3)Ni_(1/3)Mn_(2/3)O_(2) has attracted wide attention due to its excellent capacity and high working voltage.However,it suffers from undesired P2-O2 phase transition,which leads to a drastic change in volume and rapid capacity decay.Here,a P2-Na_(0.67)Ni_(0.18)Cu_(0.10)Mg_(0.05)Mn_(0.67)O_(2)(NCMM-10-05)cathode was synthesized through solid-state method with synergetic substitution of Cu and Mg.The results indicated that the incorporation of Cu and Mg suppressed irreversible P2-O2 phase transition when charging to high voltage and initialized OP4 phase formation,which improved reversible stability of structure.Thus the as-obtained material exhibited excellent electrochemical performance,which delivered an initial discharge capacity of 113 mAh·g^(-1) in the voltage range of 2.00-4.35 V(vs.Na^(+)/Na),a reversible capacity of 64.1 mAh·g^(-1) at 8C(1C=100 mA·g^(-1)),and a capacity retention of 88.9%after 200 cycles at 1C.The effect of Cu and Mg synergetic substitution on the structure and electrochemical properties of P2-type layered oxides was explored,and the specific roles played by Cu and Mg in the structural evolution were further investigated by in situ X-ray diffraction(XRD)analysis and density functional theory(DFT)calculations.This work provides a new insight into the rational design of highly stable cathode materials with rapid Na+transport capability for SIBs.
作者
朱志杰
申明远
吴涛
李文翠
ZHU Zhijie;SHEN Mingyuan;WU Tao;LI Wencui(School of Chemical Engineering,Dalian University of Technology,Dalian 116024,China)
出处
《无机材料学报》
北大核心
2025年第2期184-195,I0001-I0003,共15页
Journal of Inorganic Materials
基金
国家自然科学基金(22075038)。
关键词
钠离子电池
正极材料
P2型层状氧化物
协同取代
sodium-ion battery
cathode material
P2-type layered oxide
synergetic substitution
作者简介
朱志杰(2001-),男,硕士研究生.E-mail:374470898@mail.dlut.edu.cn;通信作者:李文翠,教授.E-mail:wencuili@dlut.edu.cn。
