Boosting Energy Storage via Confining Soluble Redox Species onto Solid-Liquid Interface

An upswell in the demand for both high energy density and large power density has triggered extensive research in developing next-generation energy storage systems (ESSs), including redox-enhanced electrochemical capacitors, metal-sulfur (Li-S and Na-S) batteries, and metal-iodine (Li-I-2, Na-I-2, etc.) batteries, which involve a liquid reaction pathway that decouples the reaction kinetics from the sluggish ion diffusion in the solid phase. Development is plagued at present by the shuttle effects of soluble redox species (SRSs) resulting in poor cycling stability and rapid self-discharge. Based on the shuttle mechanisms of SRSs, it is crucial to build an atomic or molecular relationship between the electrode surface and SRSs, that is, solid-liquid interface. Here, a timely review of current advances towards the confinement of SRSs in ESSs through solid-liquid interfacial manipulation at the atomic/molecular level is presented. Particularly, the immobilization mechanisms of SRSs around electrode materials within a series of successful examples are highlighted. The corresponding promising research avenues and challenges via interfacial manipulations are also outlined. With this work as a background, new insights into promising strategies that effectively confine the SRSs around electrodes are discussed, with the aim to facilitate vertical leaps in the performance of next-generation ESSs.

Automated summary

This review article discusses the current advances in confining soluble redox species (SRSs) in energy storage systems through solid-liquid interfacial manipulation at the atomic/molecular level. Successful examples of immobilization mechanisms of SRSs around electrode materials are highlighted, along with outlining promising research avenues and challenges in interfacial manipulations. The aim is to facilitate vertical leaps in the performance of next-generation energy storage systems.