Breaking intramolecular hydrogen bonds of polymer films to enable dendrite-free and hydrogen-suppressed zinc metal anode

Abstract

Zn-based energy storage devices such as Zn ion hybrid capacitor (ZICs) and Zn ion batteries (ZIBs) have attracted extensive attention due to the advantages of low cost, chemical stability, and high capacity of Zn metal anode. However, the Zn anode faces the difficulties of inevitable dendrite growth and hydrogen evolution reaction (HER) during cycling. Herein, we construct guar gum film, as artificial solid electrolyte interphase, on the Zn metal to suppress the dendrite grown and promote Zn deposition. Meanwhile, the Zn2+ desolvation process is enhanced by regulating the hydrogen bonding inside the film. As a result, the Zn anode coated with guar gum with rich free hydroxyl groups (RFH-GG@Zn) remains a low overpotential (45 mV) after an alternant plating/stripping process for more than 2,500 h. The application of RFH-GG@Zn promotes the cycling performance and rate ability of ZICs and ZIBs. This work aims to prepare high-performance Zn metal anodes by reducing intramolecular hydrogen bonding to enhance the protective effect of the coating on Zn anodes.