Polymer electrolyte based on chemically stable and highly conductive alkali-doped polyoxadiazole for direct borohydride fuel cell

Solid electrolyte membranes based on alkali-doped poly (4, 4’-diphenylether-1, 3, 4-oxadiazole) were first introduced into direct borohydride fuel cell (DBFC). The membranes, with outstanding thermal and chemical stability, showed comparable ion conductivity to Nafion® 115 in alkaline solution and peak power density of 146 mW cm−2 at the temperature of 40 °C. Furthermore, no weight loss was observed after soaking the membrane in 3 M NaOH solution for 10 days, indicating its excellent chemical stability in alkaline conditions. These results revealed the great potential of alkali-doped polymer for DBFC application.

► Solid electrolyte membranes based on alkali-doped polyoxadiazole were first used in DBFC applications.
► The membrane showed good thermal stability and excellent endurance in alkaline solution.
► High ion conductivity was obtained via simple doping method.
► The alkali-doped membrane outmatched Nafion 115 in DBFC single cell tests.