Synergetic effects of inorganic sepiolite filler and electroactive polyaniline on the physical and charge transport properties of polyaniline-layered phosphonated PVA–sepiolite membranes

at 5% of sepiolite content. The storage modulus and loss tangent showed membrane stability up to 80 °C, with the storage modulus as high as 320 MPa. In the EIS, equivalent circuit modelling was used to study various resistive and capacitive processes at the electrode/membrane interface and through the membrane bulk. SEP content increased bulk membrane capacitive charging owing to higher water retention in the membranes. Surface PANI layering significantly improved the charge transport, reduced the overall resistance, and increased the capacitance by 2-3 orders of magnitude across both electrode and bulk phases. This work validates a strategy for developing robust PEM system for PEMFCs by precisely adjusting physical and charge transport properties.