In Situ Integrating Highly Ionic Conductive LDH-Array@PVA Gel Electrolyte and MXene/Zn Anode for Dendrite-Free High-Performance Flexible Zn-Air Batteries

Low interfacial ion transfer kinetics and structure instability of solid-state electrolytes are the bottleneck which seriously limits the working life and energy density of flexible zinc-air batteries (ZABs). Herein, an optimized electrode-electrolyte integrated MXene/Zn-layered double hydroxides (LDH)-array@PVA structure is developed via an electrochemical Zn deposition, in situ LDH growth, polymer infiltration, and crosslinking route, integrating anode and gel polymer electrolyte (GPE) for high-performance flexible ZABs. The highly orientated hydrophilic CoNi-LDH arrays sufficiently crosslink with poly(vinyl alcohol) (PVA) chains, which effectively decreases the crystallinity degree of the PVA polymer and provides fast ionic diffusion channels to reduce the ionic transport barrier, endowing LDH-array@PVA GPE with significantly improved ionic conductivity, water retention capability, and mechanical flexibility. Moreover, the optimized anode-GPE integrated interface of MXene/Zn-LDH-array@PVA demonstrates excellent interfacial compatibility and stability, effectively reduces the interfacial impedance, and promotes the interfacial ionic transfer kinetics, enhancing a uniform zinc deposition without dendrite formation. The optimized ionic transfer kinetics and stable anode-GPE integrated interface bring the MXene/Zn-LDH-array@PVA-based flexible ZAB a long cycling life up to 50 h, and a high power density of 92.3 mW cm(-2). The rationally designed in situ crosslinking and integration strategies provide enlightening pathways for the design of high-performance flexible ZABs.

Automated summary

In this study, an optimized electrode-electrolyte integrated MXene/Zn-layered double hydroxides (LDH)-array@PVA structure is developed to improve the working life and energy density of flexible zinc-air batteries (ZABs).