A highly-proton conductive poly(vinyl alcohol)/silica nanocomposite membrane for PANI@GNP symmetric supercapacitor separator

Abstract

Polyaniline (PANI) has potential as an anode and cathode for proton based batteries (PBs) owing to its high energy density (295 mAh g−1) and excellent reversible redox activity. Achieving proton electrolytes with fast single-proton conduction behavior, separator-required mechanical properties and good proton transport channel is essential but extremely challenging for the practical success of PBs. Herein, this proton separator is constructed with nano-silica grid points in polyvinyl alcohol (PVA) chains cross-linked by sulfuric acid. Results show that PVA/inorganic composite proton membrane (PIC-PM) can immobilize the sulfate anions and help dissociate H+, which leads to a high ionic conductivity (8.6 × 10−2 S cm−1). Moreover, PIC-PM shows enough toughness and mechanical strength to puncture resistance. When the PIC-PM was applied to assemble a PANI@GNP symmetric supercapacitor, it delivers a high capacity of 943.1 F/g at 0.5 A/g; a rate capability of 74.9 % with the current density increasing from 0.5 to 5 A/g; and a capacity retention rate of 84.3 % after 1000 cycles in a current density of 3.5 A/g.