MXene-ReinforcedInterpenetrating Network Hydrogelfor Dendrite-Free Zinc Anodes

Abstract

Aqueous zinc-ion batteries (AZIBs) have become highly promising candidates for large-scale energy storage applications due to their inherent safety, cost-effectiveness, and environmentally friendly properties. Nevertheless, issues like the growth of zinc dendrites, undesirable side reactions at interfaces, and uneven ion distribution pose significant barriers to their widespread commercial adoption. Hydrogel electrolytes, with their cross-linked 3D networks, offer a solution by suppressing dendrite growth and preventing short circuits. Traditional fabrication approaches based on hydrogel synthesis and subsequent electrolyte immersion often yield inhomogeneous salt distribution profiles, consequently introducing substantial variations in electrochemical properties across different production batches. To address this, we developed an in situ synthesis strategy for MXene-reinforced polyacrylamide–poly(vinyl alcohol) (PAM–PVA) interpenetrating network (IPN) hydrogel electrolytes, which effectively regulates microstructure to inhibit dendrite formation. The composite hydrogel electrolytes exhibit exceptional mechanical properties (∼300% tensile strain), enabling robust resistance to dendrite penetration. Moreover, the synergistic interaction between MXene’s 2D lamellar structure and zinc trifluoromethanesulfonate (Zn(OTf)₂) enhances ion transport uniformity and optimizes interfacial reactions. Electrochemical evaluations reveal exceptional durability: Zn//Zn symmetric cells maintain stable operation for more than 1900 h at 1 mA cm^–2 without dendritic formation, whereas Zn//MnO₂ full cells retain 70.4% of their capacity after 1500 cycles at a current density of 2 A g^–1. This work provides insights into the structure–activity relationship of MXene-reinforced hydrogels. It elucidates the mechanistic role of MXene-based composite hydrogels in suppressing zinc dendrite formation, thereby establishing both a theoretical framework and a practical methodology for designing high-performance electrolytes for AZIBs. These findings provide critical advances toward developing reliable and scalable aqueous zinc-ion battery systems suitable for practical grid-scale energy storage implementations.