Tamirat Andebet Gedamu, Guan Xuze, Liu Jingyuan, Luo Jiayan, Xia Yongyao
Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Institute of New Energy, Fudan University, Shanghai 200433, People's Republic of China.
School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
Chem Soc Rev. 2020 Oct 19;49(20):7454-7478. doi: 10.1039/d0cs00489h.
Redox mediators (RMs) play pivotal roles in enhancing the performance of electrochemical energy storage and conversion systems. Unlike the widely explored areas of electrode materials, electrolytes, separators, and electrolyte additives, RMs have received little attention. This review provides a comprehensive discussion toward understanding the effects of RMs on electrochemical systems, underlying redox mechanisms, and reaction kinetics both experimentally and theoretically. Our discussion focuses on the roles of RMs in various electrochemical systems such as lithium-ion batteries, Li-O2 batteries, Li-S batteries, decoupling electrolysis, supercapacitors, and microbial fuel cells. Depending on the reaction regions where the RMs become active, we can classify them into bulk, solid-solid interfacial, solid-liquid interfacial, and cell-unit RMs. The prospect of developing RMs with effective charge transfer properties along with minimal side-effects is an exciting research direction. Moreover, the introduction of an efficient RM into an electrochemical system can fundamentally change its chemistry; in particular, the electrode reaction polarization can be considerably decreased. In this context, we discuss the key properties of RMs applied for various purposes, and the main issues are addressed.
氧化还原介质（RMs）在提升电化学储能与转换系统的性能方面发挥着关键作用。与电极材料、电解质、隔膜以及电解质添加剂等已被广泛研究的领域不同，氧化还原介质受到的关注较少。本综述对氧化还原介质在电化学系统中的作用、潜在的氧化还原机制以及反应动力学进行了全面的实验和理论探讨。我们的讨论聚焦于氧化还原介质在各种电化学系统中的作用，如锂离子电池、锂氧电池、锂硫电池、解耦电解、超级电容器和微生物燃料电池。根据氧化还原介质发挥作用的反应区域，我们可将其分为本体、固-固界面、固-液界面和电池单元氧化还原介质。开发具有有效电荷转移性能且副作用最小的氧化还原介质是一个令人兴奋的研究方向。此外，将高效的氧化还原介质引入电化学系统可从根本上改变其化学性质；特别是，电极反应极化可显著降低。在此背景下，我们讨论了用于不同目的的氧化还原介质的关键特性，并解决了主要问题。
