Construction of Continuous Proton Transport Channels via Anchoring Strong Proton Conductor on Graphene Oxide in Sulfonated Poly (Ether Ether Ketone)

Abstract

Constructing continuous proton transport channels in proton exchange membranes (PEMs) has been considered as an efficient strategy to improve proton conductivity. In this work, a water-insoluble hybrid graphene oxide (HDGO) is prepared via the hydrothermal reaction between polydopamine-coated graphene oxide (DGO) and a strong proton conductor phosphotungstic acid (HPW), in which HPW is chemically bonded onto DGO. The two-dimensional structure of DGO and the strong acidity of HPW favor the rapid proton transport in the sulfonated poly(ether ether ketone) (SPEEK) membranes. As compared to that of the SPEEK control membrane, the proton conductivity of the SPEEK composite membrane containing 6 wt% HDGO increases from 0.035 to 0.061 S cm⁻¹ at 25°C, an increase of ~75%. The composite membrane containing 10 wt% HDGO exhibits ~49% lower area swelling ratio than the SPEEK control membrane. Meanwhile, the proton conductivity of the composite membrane remains stable during the 1440 h immersing in liquid water.