钠离子电池用高稳定性锰基层状正极材料研究

钠离子电池资源丰富、价格低廉，是大规模储能技术的理想选择。锰基层状氧化物由低成本元素组成，并且可逆容量大、结构灵活可调，因此作为钠离子电池正极材料具有极大的应用前景。然而，层状锰基氧化物当暴露于空气或电化学循环时，常常遇到严重的化学稳定性和电化学稳定性的问题。本项目旨在为锰基层状材料的稳定性问题提供解决方案，从而改善材料的电化学储钠性能。本项目将深入研究锰基层状材料在湿态空气中的水或二氧化碳化学嵌入材料的微观机制，揭示不同电解液体系对锰溶解的影响，采用多种体相掺杂和表面修饰优化锰基层状材料的组成和微观结构，另外也通过构筑多相共生结构，增强充放电过程中的结构稳定性。本项目力争发展具有高环境稳定性的钠离子电池用锰基层状正极材料，也可为高性能电极材料的设计提供新思路。

Sodium-ion batteries (SIBs) are promising in large-scale energy storage due to the low cost and abundance of sodium. Manganese-based layered oxides have been one of the most popular cathodes due to the high reversible capacity via use of earth-abundant elements. However, Mn-based layered oxides always meet the serious issues of chemical and electrochemical stability, when exposed to moisture air or electrochemically cycled in organic electrolyte. This project will mainly focus on finding solution to elevate the chemical and electrochemical stability of Mn-based layered oxides and then improve sodium storage performance. We will carry out in-depth investigation on the mechanism for chemically inserting H2O or CO2 into Mn-based layered oxides, reveal the relationship between various electrolytes and manganese dissolution in electrochemical cycling process, employ bulk doping and surface modification to further optimize the composition and microstructure of Mn-based layered oxides, additionally construct the multiphase intergrowth to enhance the structural stability of Mn-based layered oxides during charging and discharging. Consequently, this project will develop highly stable Mn-based layered oxides for superior sodium storage performance and provide new insight into the design of high-performance electrodes for SIBs.