Reactivity of TiS2 Anode towards Electrolytes in Aqueous Lithium‐Ion Batteries

Abstract

AbstractAqueous rechargeable batteries are appealing alternatives for large‐scale energy storage. Reversible cycling of high‐energy aqueous batteries has been showcased using highly concentrated aqueous electrolytes, which lead to a significantly suppressed water activity and formation of a stable solid‐electrolyte interphase (SEI). However, the high salt concentration inevitably raises the cost and compromises the environmental sustainability. Herein, we use layered TiS2 as a model anode to explore the feasibility of cycling aqueous cells in dilute electrolytes. By coupling three‐electrode cycling data with online electrochemical mass spectrometry measurements, we depict the potential‐dependent gas evolution from the cell in the absence of a stable SEI. We offer a comprehensive mechanistic understanding of the complex interfacial chemistry in dilute electrolytes, taking into account material reactivity and interfacial compatibility. Design strategies and research directions of layered‐type electrodes for sustainable aqueous batteries with dilute electrolytes are recommended, based on the scientific discovery presented in this work.