A new fabrication method of an intermediate temperature proton exchange membrane by the electrospinning of CsH2PO4

A novel method for the fabrication of an intermediate temperature proton conducting composite membrane was developed. Cesium dihydrogen phosphate, CsH2PO4 (CDP), was electrospun to obtain a highly interconnected proton conducting fibre mat. CsH2PO4 was heat treated above its dehydration temperature (Tdehy ∼ 230 °C) in order to induce a partial polymerisation. The partially polymerised material produced a viscous aqueous solution which could be electrospun in the absence of a carrier polymer, thus leading to pure inorganic fibres. The electrospun fibre mats were characterised in terms of composition, structure and morphology by XRD, MAS NMR and SEM and their proton conductivity determined by electrochemical impedance spectroscopy. The electrospun fibres (CDPf) showed a maximum proton conductivity of 8 × 10−3 S cm−1 at 250 °C.