钠离子电池锰基正极材料的元素替位掺杂改性研究进展

Research progress on element substitution doping modification of manganese-based cathode materials for sodium-ion batteries

为提高钠离子电池锰基过渡金属氧化物正极材料的容量保持率,有效抑制循环过程中不可逆相变的发生,采用过渡金属位替代(M′-M)、碱金属位Li替代(Li-A)、过渡金属位以及碱金属位Li双取代(Li-M、A)的锰基TMO制备过程,利用较低线性有序性对锰基TMO材料进行结构稳定改性。综合分析表明,锰基TMO材料经过不同元素过渡金属位替代、碱金属位替代、过渡金属位以及碱金属位Li双取代均不同程度抑制了Jahn-Teller效应。改性后的锰基TMO中过渡金属层间距和Na+扩散速率增大,容量保持率和结构稳定性得到显著提高,其中经碱金属Li元素掺杂后的锰基TMO容量保持率最高升至94.3%。

In order to improve the capacity retention rate of manganese-based transition metal oxide(TMO)cathode materials for sodium-ion batteries and effectively inhibit the occurrence of irreversible phase transitions during cycling,manganese-based TMO is prepared through using transition metal position substitution(M′-M),alkali metal position Li substitution(Li-A),transition metal position-alkali metal position Li double substitute(Li-M,A).The structure stability of manganese-based TMO materials is modified by means of lower linear order.Comprehensive analysis shows that the Jahn-Teller effect is inhibited to varying degrees by transition metal substitution,alkali metal substitution,transition metal position-alkali metal position Li double substitution of manganese-based TMO materials.Both the transition metal layer spacing and Na+diffusion rate in the modified manganese-based TMO increase,and the capacity retention rate and structural stability are significantly improved.Of which the capacity retention rate of manganese-based TMO after doping with alkali metal Li increases to 94.3%.