In‐Situ Spontaneous Electropolymerization Enables Robust Hydrogel Electrolyte Interfaces in Aqueous Batteries

Abstract

Hydrogels hold great promise as electrolytes for emerging aqueous batteries, for which establishing a robust electrode‐hydrogel interface is crucial for mitigating side reactions. Conventional hydrogel electrolytes fabricated by ex‐situ polymerization through either thermal stimulation or photo exposure cannot ensure complete interfacial contact with electrodes. Herein, we introduce an in‐situ electropolymerization approach for constructing hydrogel electrolytes. The hydrogel is spontaneously generated during the initial cycling of the battery, eliminating the need of additional initiators for polymerization. The involvement of electrodes during the hydrogel synthesis yields well‐bonded and deep infiltrated electrode‐electrolyte interfaces. As a case study, we attest that, the in‐situ formed polyanionic hydrogel in Zn‐MnO2 battery substantially improves the stability and kinetics of both Zn anode and porous MnO2 cathode owing to the robust interfaces. This research provides insight to the function of hydrogel electrolyte interfaces and constitute a critical advancement in designing highly durable aqueous batteries.

Hydrogel-stabilized zinc ion batteries: progress and outlook

“…Chen et al describe a method for preparing hydrogel electrolytes by in situ electro-polymerization. 91 The hydrogel was generated spontaneously during the initial cycling of the battery and did not require an additional initiator for polymerization. The involvement of electrodes during hydrogel synthesis produced a well-bonded and deeply permeable electrode-electrolyte interface.…”

Competitive Tradeoff between Zn Deposition and Hydrogen Evolution Reaction on Zn-Metal Anode

“…Concentrated electrolytes can effectively regulate the solvation structure of Zn 2+ and reconfigure the hydrogen bonds of the electrolyte. It is generally believed that as the concentration of Zn 2+ increases, the number of water molecules coordinated with Zn 2+ decreases, which reduces the chemical reactivity of water, alleviates the HER, suppresses dendrite growth, and improves the electrochemical performance. − …”