The Effects of Sulfonated Graphene Oxides (sGO) on Ion Conductivity and Permeability of the Vanadium Redox Flow Batteries Membranes Based on Sulfonated Poly(Ether Ether Ketone) Composite

Sulfonated graphene oxide (sGO) was used as a filler to enhance performance of sulfonated poly(ether ether ketone)(sPEEK) membrane. The sGO was firstly prepared by treating graphene oxides (GO) with sulfanilic acid at 70 °C for 20 h. The sGO was characterized by FTIR and XPS techniques. Composite membranes of various amount of sGO were fabricated via solution casting method. The properties of composite membranes were investigated by measuring ion exchange capacity (IEC), water uptake, ion conductivity and vanadium ion permeability. From the results, it was found that the IEC and water uptake of the membranes increased after adding the sGO. Ion conductivity of the sPEEK membrane also increased from 8.94*10-3 Scm-1 to 10.55*10-3 Scm-1. Moreover, permeability of vanadyl sulfate (VOSO4) through the composite membranes were decreased. These composite membranes exhibit great potential for vanadium redox flow batteries application.