锂空气电池中锰氧化物催化剂与过氧化锂的界面结构及其催化机理的理论模拟

项目名称： 锂空气电池中锰氧化物催化剂与过氧化锂的界面结构及其催化机理的理论模拟

项目编号： No.21503182

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 马忠云

作者单位： 湘潭大学

项目金额： 21万元

中文摘要： 锂空气电池因其具有很高的理论能量密度而受到极大的关注，但是也面临充放电效率低、可逆性差、功率密度小等严峻挑战，而在正极中应用高效的催化剂是有效提高电池实际性能的一个重要途径。本项目拟运用第一性原理模拟计算为主要手段，研究以MnO2为代表的锰氧化物催化剂与Li2O2的界面结构及其催化机理。我们首先构建不同的台阶式界面结构模型，然后运用密度泛函理论(DFT)和热力学计算，研究MnO2催化剂参与下Li2O2在表面上和界面的分解和形成的反应机理，给出反应能量曲线，考察不同的界面结构与催化性能的关系；并探讨MnO2的表面O缺陷的作用以及O2的迁移与脱附机制，揭示催化剂作用的本质。预计所得结果将为理性设计更高效的催化剂和电极结构提供理论指导。

中文关键词： 密度泛函理论计算；二氧化锰；锂空气电池；界面反应；表面电子结构

英文摘要： Li-air batteries have attracted great interests for their ultra-high theoretical energy density, however, they also are facing substantial challenges, such as low efficiency of charging and discharging, poor reversibility, and low power density. Better practical performances of the battery could be achieved by applying the high-efficient catalysts in the cathode. In this project, we plan to employ the first-principles methods to investigate the interfacial structures between the manganese-oxide catalysts represented by MnO2 and the Li2O2,and the corresponding catalytical mechanism. First of all, the models with different stepped-interfacial strucutres are built based on the single crystal surfaces.Then we perform the density functional theory-based method and the thermodynamic calculations to explore the process of Li2O2 decomposition and formation on the suface and the interface in the presence of MnO2, meanwhile obtain the energy profiles. Moreover, we will study the interfacial strucutre and catalytic properties as well as O2 diffusion and desorption from the surface. Finally the origins of the catalyst are decuced. The conclusions of this modeling will provide a guide to rational design the more effective catalysts and the electrode structures that could be used directly in the new battery systems.

英文关键词： density functional theory calculation;manganese-dioxide;lithium air battery;interfacial reaction;surface electronic structure