The work is structured as follows. First, we describe the measuring equipment, the experimental procedures and the protocols employed to prepare the electrolyte samples and measure their physical properties. In a second part, we present the density and viscosity data as well as their changes with all the aforementioned parameters. We also provide multivariate regression fits that capture the variation of the electrolyte properties in all parameter space. This paper comes with Supplementary Information materials, mainly describing the quantification of the sulfate and vanadium concentrations. The Supplementary Information also contains additional density and viscosity plots and details about the empirical regression of viscosity. Finally, as part of our open science commitment, we provide the raw density and viscosity data in csv format.