Widely used conductive carbon is found to be a major capacity contributor towards the sodium storage while used in electrode composition, in conjunction with NaClO4-PC electrolyte. Experimental studies show that the surface adsorbed sodium is present, confirmed by microscopic and XRD analysis. This unexpected property towards sodium storage in electrode conceals the electrochemical contributions expected from an active material. As the conductive carbon is a desirable component in sodium battery development, therefore this contribution needs to be optimized with respect to Coulombic efficiency. In order to investigate and optimize the unwanted capacity contribution from carbon containing electrode, we introduce an electrolyte system comprise of NaClO4-TEGDME, a low-cost electrolyte over extensively used PC-based compositions. This electrolyte composition controls the reversible capacity contribution to a minimum from the conductive carbon, and showed up to similar to 97% reversibility with adequate stability till 100 cycles, within the potential range from 0.1 to 3 V. A detailed experimental analysis has been carried out to establish the electrolyte composition against conductive carbon. (C) 2017 Elsevier B.V. All rights reserved.