Enhanced Proton Conductivity from Phosphoric Acid-Incorporated 3D Polyacrylamide-Graft-Starch Hydrogel Materials for High-Temperature Proton Exchange Membranes

摘要

To enhance anhydrous proton conductivity of high-temperature proton exchange membranes (PEMs), we report here the realization of H_3PO_4-imbibed three-dimensional (3D) polyacrylamide-graft-starch (PAAm-g-starch) hydrogel materials as hightemperature PEMs using the unique absorption and retention of crosslinked PAAm-g-starch to concentrated H_3PO_4 aqueous solution. The 3D framework of PAAm-g-starch matrix provides enormous space to keep H_3PO_4 into the porous structure, which can be controlled by adjusting crosslinking agent and initiator dosages. Results show that the H_3PO_4 loading and therefore the proton conductivities of the membranes are significantly enhanced by increasing the amount of crosslinking agent and initiator dosages. Proton conductivities as high as 0.109 S cm~(-1) at 180℃ under fully anhydrous state are recorded. The high conductivities at high temperatures in combination with the simple preparation, low cost, and scalable matrices demonstrate the potential use of PAAm-g-starch hydrogel materials in hightemperature proton exchange membrane fuel cells.