Proton-Conducting Polyelectrolyte Membranes Containing Graphene Dots for Moisture Electric Generators

Polyelectrolyte membranes used in moisture-electric generators (MEGs) typically face the challenge of producing high voltage but low current. In this study, a PSSA/PVA/GDs membrane (PPGM) was developed by incorporating graphene dots (GDs) into the poly(styrene sulfonic acid) (PSSA) and poly(vinyl alcohol) (PVA) composite system. The abundant oxygen-containing groups in GDs enhance hydrogen bonding and increase the cross-linking density, thereby improving the tensile strength of the PPGM to 25.77 MPa. Additionally, GDs endow the polyelectrolyte membrane with excellent hydrophilicity and a notable self-healing capability. The uniform dispersion of GDs, coupled with their excellent electrical properties, facilitates the formation of rapid proton transport channels, which, in turn, enhances the ionic conductivity to 1.41 S/m. Under a relative humidity (RH) of 83%, the membrane (1 cm 2 ) can deliver an open-circuit voltage ( V OC ) of 0.31 V and a high short-circuit current ( I SC ) of 23 μA, and the high electric current (approximately 23 μA) can be sustained for up to 120 min. The current output performance of this membrane exceeds that of the pristine PSSA/PVA membrane, and this work is anticipated to advance the application of a traditional polyelectrolyte membrane in the field of MEGs.