A flexible zinc–air battery with a high ionic conductivity gel polymer electrolyte and CoP-based bifunctional air cathode

A gel polymer-based electrolyte (GPE) is developed by infusing SiO₂ and cross-linking with polyethylene oxide (PEO) into a sodium polyacrylate (PANa)-bonded network, which significantly enhances the mechanical properties and ionic conductivity of GPE. Impressively, optimized GPE delivered room temperature ionic conductivity up to 353 mS/cm 2 and showed the elongation capability of over 500%, hence making it an efficient GPE for flexible electronics. An air cathode was also developed using a CoP-based electrocatalyst, which was confirmed through various characterization tools, including X-ray diffraction studies, X-ray photoelectron spectroscopic studies, and morphological analysis. Upon electrochemical analysis, the developed CoP-based electrocatalysts exhibited an OER overpotential of 1.47 V and an ORR half-wave potential of 0.65 V, which is comparable to that of standard RuO₂-Pt/C electrocatalysts. As developed CoP electrocatalysts surpassed standard electrocatalysts, the CoP-based air cathode was developed to create a flexible Zinc air battery (FZAB) with optimized GPE. The FZAB with optimized GPE and CoP-based air cathode exhibited an operating potential of 1.65 V, a peak power density of 93 mW/cm², and stability of over 95 h, which is also compared with RuO₂/Pt-C-based air cathode-based FZAB. The work here provides a promising approach to developing desirable hydrogel electrolytes for FZAB applications. • Developed a SiO₂-infused, PEO cross-linked PANa-based hydrogel electrolyte with enhanced ionic conductivity and mechanical strength. • Optimized GPE achieved room-temperature ionic conductivity of up to 353 mS/cm and an elongation capability of over 500%. • CoP-based electrocatalysts exhibited superior OER (1.47 V) and ORR (0.65 V) activity compared with RuO₂/Pt-C benchmarks. • The flexible zinc–air battery using optimized GPE and CoP air cathode delivered an OCP of 1.65 V, peak power density of 93 mW/cm², and stable cycling for over 95 h. • Demonstrated a promising strategy for developing durable, high-performance hydrogel electrolytes in flexible energy storage and electronics.