An Investigation of Proton Conductivity in Zeolite Beta Composite Membranes: Towards Quasi-Solid-State Proton Batteries

Zeolite composite membranes provide a compelling path toward stable quasi-solid proton electrolytes. This study evaluates the through-plane proton conductivity of H-form Zeolite Beta/polyvinylidene fluoride (H-Beta:PVDF) membranes post-activation in aqueous sulfuric acid. Membranes were characterized via electrochemical impedance spectroscopy between blocking electrodes and modeled using an Rs + (Rb∥CPEb) equivalent circuit where Rs is the series resistance, Rb is the bulk resistance, and CPEb is the bulk constant phase element. Apparent ionic conductivities ranged from 2.31 × 10−6 to 1.53 × 10−5 S cm−1. Bulk CPE exponents were observed between 0.42 and 0.87, suggesting non-ideal impedance responses.