Network-reinforcing HACC-co-PAM hydrogel electrolytes for suppressed zinc dendrite growth and high-performance zinc-ion batteries

Abstract

Zinc-ion batteries (ZIBs) are regarded as one of the most promising energy storage technologies due to their low cost and high safety. However, their practical applications are severely hindered by uncontrolled zinc dendrite growth and detrimental side reactions. Herein, this study integrates a quaternized chitosan (HACC) network with a polyacrylamide (PAM) network to fabricate a dual-network hydrogel electrolyte (HACC-co-PAM). The intermolecular network is formed via hydrogen bonds between the –NH₂ and the –OH group, as well as coordination bonds between (CH₃)₃N⁺ Cl⁻ and ZnSO₄. The covalently crosslinked PAM network serves as the second network. Electrostatic interactions between the functional groups (carbonyl and –OH) in HACC-co-PAM and Zn²⁺ homogenize the Zn²⁺ flux. The abundant functional groups on HACC-co-PAM form an interwoven hydrogen bond network and form strong interactions with water to inhibit side reactions. The growth of Zn dendrites is effectively suppressed. The HACC-co-PAM electrolyte exhibits an exceptional ionic conductivity of 16.8 mS cm⁻¹ and remarkable plasticity with 590% strain. The symmetric Zn–Zn cell operates stably for 550 hours at 1 mA cm⁻², while the Zn–MnO₂ cells deliver a specific capacity of 160 mA h g⁻¹ after 100 cycles. This work provides valuable insights into the design of advanced hydrogel electrolytes for high-performance ZIBs.