从Li-O2电池到Li-CO2电池：反应机理的计算研究与正极催化剂的设计

Increasing requirements are needed for energy storage technology from electric vehicles and smart grids, and it is urgent to develop new energy storage systems such as Li-air batteries. In this proposal, by combining density functional theory (DFT) computations and molecular dynamics (MD) simulations with experiments, we aim to deeply investigate the fundamental physical chemical problems involved in the air cathode processes of Li-O2 and Li-CO2 batteries, explore the electrocatalytic mechanisms about the reduction and evolution reactions of O2 and CO2, design composite catalysts based on carbon nanomaterials and transition metal or oxide nanoparticles, improve the electrochemical reversibility and cyclic stability of Li-O2 batteries, clarify the effects of CO2 on the cell reactions, and overcome the key barriers from Li-O2 batteries to Li-air batteries. Also, we would elucidate the electrochemical reaction mechanism of Li-CO2 batteries, and design catalysts to enhance the kinetic performances, so as to realize the application of CO2 to energy storage devices, and provide a new strategy for the recycle and reuse of the greenhouse gas CO2.

电动汽车和智能电网等对储能技术提出了更高的要求，急需发展Li-空气电池等新的储能体系。本申请通过密度泛函理论(DFT)计算和分子动力学(MD)模拟与实验相结合，深入研究Li-O2和Li-CO2电池空气正极反应过程中涉及的基本物理化学问题，探索O2和CO2还原和析出反应的电催化机理，设计基于碳纳米材料与过渡金属或其氧化物纳米颗粒的复合催化剂，提高Li-O2电池的电化学可逆性和循环稳定性，揭示CO2对Li-O2电池反应的影响，克服从Li-O2电池过渡到Li-空气电池的关键障碍。同时揭示Li-CO2电池的电化学反应机理并设计催化剂改善其动力学性能，将CO2用作储能体系，为温室气体CO2的回收和利用提供新思路。

本项目通过计算与实验相结合研究了Li-O2电池和Li-CO2电池的电化学反应机理。基于对反应机理的深刻认识，设计了富氮碳材料及其与金属或金属氧化物纳米颗粒的复合材料等系列空气电极催化剂，显著改善了Li-O2电池综合性能。基于CO2电催化转化机理构筑了可充电Li-CO2电池，探索了石墨烯、碳纳米管及其与金属或金属氧化物纳米颗粒的复合材料用作空气电极催化剂，并尝试了LiBr用作电解液氧化还原介质，引领了CO2储能新体系的深入发展。已发表研究论文13篇和综述3篇，其中7篇发表在Adv. Mater.、Angew. Chem. Int. Ed.等影响因子10以上的期刊。论文发表后被SCI引用400余次，1篇论文进入ESI近10年高被引论文。