Polyethersulfone/polyvinylpyrrolidone/boron nitride composite membranes for high proton conductivity and long-term stability high-temperature proton exchange membrane fuel cells

Abstract

Proton exchange membranes have excellent proton conductivity and long-term endurance vital for high-temperature proton exchange membrane fuel cells (HT-PEMFCs). Herein, a polyethersulfone (PES)/polyvinylpyrrolidone (PVP)/boron nitride (BN) (PES–PVP–BN) composite membrane was fabricated successfully. The well-dispersion of BN nanosheets in the PES–PVP–BN composite membrane was demonstrated by scanning electron microscopy and energy dispersive X-ray spectrometry mapping. Benefiting from the interaction force between BN nanosheets with phosphoric acid (PA), the PA doping level (ADL) and conductivity of the blend membrane have been improved. In addition, the interaction force between the PVP@BN system and PA has been demonstrated by theoretical calculations, which enhances the anchoring effect of BN to PA compared with the PES–PVP membrane significantly. Thus, the PES–PVP–0.5% BN composite membrane exhibited the best proton conductivity (107.42 mS cm−1) and peak power density (359 mW cm−2) at 160 °C under the same device operation conditions. Furthermore, the PES–PVP–0.5% BN composite membrane exhibited outstanding long-term stability during a 100 h test, demonstrating the PES–PVP–BN composite membrane as a candidate material for HT-PEMFC applications.