PW9V3/rGO/SPEEK hybrid material: an excellent proton conductor

Abstract

To improve the proton conductive performance of heteropoly acids, sulfonated polyether ether ketone (SPEEK) and reduced graphene oxide (rGO) were introduced into a tungstovanadophosphoric acid (H₆PW₉V₃O₄₀, abbreviated as PW₉V₃) to prepare a hybrid film material. The results indicate that the Keggin framework of the PW₉V₃O₄₀⁶⁻ anion still remains in the hybrid material and confirm the homogeneous dispersion of PW₉V₃ on the surface of graphene sheets, which results in a better stability of PW₉V₃. The obtained PW₉V₃/rGO/SPEEK hybrid material exhibits appreciable proton conductivity of 6.2 × 10⁻² S cm⁻¹ at 17 °C and 70% relative humidity because the introduction of rGO and SPEEK into PW₉V₃ can help to form more hydrogen bonds in the HPA-based material. The conductivity of the PW₉V₃/rGO/SPEEK hybrid material enhances with the increase of temperature, and it shows Arrhenius behavior with the activation energy value of 18.7 kJ mol⁻¹, indicating that the proton conduction in this film occurs by a mixing mechanism. It is an alternative hybrid film material which may be applied in the field of proton exchange fuel cells.