基于氧活化的高稳定性锰基层状正极材料的合成及构效关系研究

氧活化作为一种电荷补偿方式，可以大大提高电极的能量密度，是发展高能量密度锂/钠离子电池的有效途径。然而，氧活化导致电压迟滞和晶体结构不稳定等问题。前期研究结果表明，材料的结构直接影响了氧活化的稳定性。在进一步对层状结构的研究中，申请人发现氧活化在O2和P3相的正极材料中较稳定。本项目在此研究基础上，对锰基层状结构的正极材料进行深入研究，通过合成不同层状结构的正极材料，探究氧活化在不同层状结构材料中的表现形式，揭示氧活化过程中所涉及的基本物理化学问题，考察激发氧活化反应的机理，设计基于锰元素的不同层状结构的锂/钠电正极材料，提高氧活化的可逆性、电极的循环稳定性和能量密度。通过密度泛函(DFT)计算和实验的结合，揭示不同的层状结构对氧活化反应的影响，克服因氧活化引起的关键障碍。同时为构筑高性能电极材料提供新的研究思路和强有力的理论支持。

As one type of charge compensation, oxygen activation increases the energy density of the cathodes obviously. And it is an effective way to develop lithium/sodium ion batteries with high energy density. However, the oxygen activation behavior induces severe problems such as voltage hysteresis and unstable crystalline structure. It is shown that the structure of cathodes directly affects the stability of oxygen activation. In additional studies, we have found that oxygen activation is stable in O2 and P3 type cathodes compared with other structures. In this project, we focus on the Mn-based cathodes with layered structure, developing cathodes with new layered structures to study the oxygen behavior in different layered structures. Meanwhile, the essential physical and chemical problems during oxygen activation will be explored for lithium and sodium-ion batteries, respectively. Then the mechanism of oxygen activation will be investigated. It is hoped that through the research of this project, some new cathodes will be developed, with high reversible oxygen activation, cycling stability, and high energy density; Furtherly, in combination with experiment and theoretical calculations, the mechanism of oxygen activation in different structure will be revealed. And then, we would like to overcome the key obstacle induced by oxygen activation. Research on the relationship between the structure design and oxygen activation will provide new research ideas and strong theoretical support for building better batteries with high energy density.