二次金属空气电池中氧析出/氧还原电催化过程的阴离子调控机制研究

Electrically rechargeable metal-air batteries demonstrate high energy density, low cost, and environmental friendliness, of which development makes curve-road overtaking entirely possible in next-generation energy storage systems for portable devices and electronic vehicles. Nevertheless, due to the existing of scaling relationships among the oxygen-containing intermediates, the catalytic activity of bi-functional oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) is limited and is difficult to be prominently improved with only cation regulation in transition metal compounds. Anion regulation of active sites is of great significance for the construction of favorable electronic structures, while it is still in infancy stages and lacks investigations of the underlying mechanism...With the aim of solving the bottleneck problem, this project focuses on a critical scientific issue of the influence of anion regulation on the electron occupancy in high energy anti-bonding dγ orbits and low energy dξ orbits of cooperated transition metal cations, which plays a predominant role in OER/ORR electrocatalysis. Through controllably regulating anion properties, probing the electron filling in cationic dγ and dξ orbits, and investigating the relationship between the regulated electron distribution in different energy-level d orbits of cation active sites and the OER/ORR electrocatalytic performance, the anion regulation mechanism of oxygen electrocatalysis is built for electrically rechargeable metal-air batteries. The investigation of the project can provide new insights on the design of favorable electronic structures for bi-functional electrocatalysis and the development of high-performance rechargeable metal-air batteries.

二次金属空气电池能量密度高、成本低且环境友好。该电池体系的开发，有望实现我国下一代电动设备的弯道超车。然而，受制于正极氧析出/氧还原反应的氧电催化过程中，不同含氧中间体吸附能之间的比例限制关系，单纯调变过渡金属阳离子，难以充分优化氧电催化行为。配位阴离子性质的调控，会影响阳离子活性位d轨道的分裂及电子的分布状态，对于氧电催化过程至关重要，但尚处探索初期，缺乏清晰的机制加以指导。. 针对上述瓶颈问题，本项目拟围绕阴离子调控过渡金属高能dγ及低能dξ轨道电子分布对其氧析出/氧还原电催化行为的影响这一关键科学问题展开。通过对过渡金属化合物中阴离子性质的可控调变、阴离子调控下金属高能dγ及低能dξ轨道电子分布情况的表征分析，并关联其电化学行为，揭示二次金属空气电池中氧析出/氧还原电催化过程的阴离子调控机制。为氧电催化活性位的设计及高性能、高安全性二次金属空气电池的构筑提供理论依据。

本项目以高性能二次金属空气电池需求为背景，针对其正极氧析出/氧还原反应催化位点阴离子调控机制缺乏认识的现状，围绕阴离子调控过渡金属电子结构对氧析出/氧还原电催化行为的影响这一关键科学问题展开。对过渡金属化合物中阴离子性质的可控调变、阴离子调控下阳离子活性位点电子分布情况，以及对电化学催化行为的影响进行研究，用以揭示二次金属空气电池中氧析出/氧还原电催化过程的阴离子调控机制。本项目按照预设计划研究内容展开，实现了过渡金属阳离子位点的电子结构可控调变、并且关联电化学行为，探明了二次金属空气电池中氧析出/氧还原电催化过程的阴离子调控机制，为高性能、高安全性二次金属空气电池的构筑提供了理论支撑。