Abstract The use of electrolyte-based nanofluid is a new approach for enhancing the performance of Vanadium Redox Flow Batteries (VRFBs). This paper, for the first time in the literature, presents an experimental study to comprehensively investigate the rheological behaviour, electrical conductivity, and thermal conductivity of a newly prepared electrochemical graphene oxide (EGO)/ vanadium (IV) electrolyte-based nanofluid in different weight concentration and bulk temperatures. SEM, FT-IR and X-ray Diffraction (XRD) characterizations were performed and different functional groups, smooth 2D layered structures, and low crystallinity were detected in our tailored oxidation EGO which are amongst the enhancing features for VRFBs electrode materials. It was observed that the optimum weight concentration of nanoparticles in the electrolyte-based nanofluid is 0.05 wt% with strong colloidal stability, enhanced electrical and thermal conductivities, and an optimal viscosity. The maximum feasible enhancements in electrical and thermal conductivities that were achieved were 12%, and 4%, respectively, which can positively affect the performance of flow battery in terms of electrochemical activity on the electrode surface and thermal management of the flow battery system. In addition, the rheological evaluation showed that the behaviour of the electrolyte-based nanofluid tends to change from Newtonian to non-Newtonian for weight concentrations higher than 0.05%. The results obtained from rheological behaviour can provide useful insights in choosing an optimum pumping system of the flow batteries working with electrolyte-based nanofluid.