Intermediate-Temperature Proton Exchange Membranes Based on Cerium Ultraphosphate Composited with Polybenzimidazole

Abstract

We report the rational fabrication and structural, thermal, mechanical, and electrochemical characterization of a new type of intermediate-temperature (IT) polymer-inorganic composite (PIC) proton exchange membranes (PEMs) that are made of cerium ultraphosphate (CeP5O14—CUP) as the solid-state proton conductor composited with a high-temperature (HT) polybenzimidazole (PBI) as the polymeric binder. Flexible PBI-CUP PIC membranes with the thickness of ~135 μm and CUP mass fraction of up to 75 % were prepared by solution-casting without additional acid-doping (e.g., phosphoric acid). The proton conductivity of the fabricated IT-PIC-PEMs was up to 5.80 × 10-2 S cm-1 as measured from a prototype IT PEM fuel cell (PEMFC) operated at 200°C in the humidified hydrogen and air environment. This type of IT-PIC-PEMs also demonstrated sufficient mechanical strength and flexibility, excellent thermal stability (up to 350°C), and very good durability of the proton conductivity (within the test duration of 500 h). The present experimental study shows the promising future of the IT-PIC-PEMs for applications in various IT electrochemical processes including IT-PEMFCs, IT-electrolyzers, etc.

Thermally processed Ni-and Co-struvites as functional materials for proton conductivity

“…In combination with their high compatibility with other cell components (electrodes, electrolytes, seals) and low cost, M-dittmarites are promising proton-conducting materials. 77,78…”