Summary
Fuel-cell membranes benefit from inorganic fillers that add mechanical strength and help retain proton conductivity, and zirconium phosphate/zirconium oxide (ZrP/ZrO2) nanofibres are attractive for this role. This work introduces a novel reactive coaxial electrospinning route to make them: a zirconium precursor and a phosphorus source are spun simultaneously from two separate solutions through a coaxial needle, which delays formation of the zirconium phosphate gel so that the reaction begins only at the interface between the two streams. The as-spun fibres are then calcined and treated with phosphoric acid, and the formation of ZrP/ZrO2 is confirmed by 31P MAS NMR, with fibre morphology depending on the solution parameters. When incorporated into the short-side-chain perfluorosulfonic acid ionomer Aquivion, the nanofibres yield composite membranes with a greater elastic modulus and yield point as well as higher proton conductivity, showing the promise of the approach for reinforced fuel-cell membranes.