In this work, lithium-modified silica nanosalt (Li202) is solution-synthesized and used as a gel-forming additive in 1.5 M tetraethylammonium tetrafluoroborate (TEABF(4))/acetonitrile (ACN) electrolyte solution for the supercapacitor with activated carbon electrode. The electrochemical properties of the supercapacitor adopting the Li202 (5 wt.%) are investigated using linear sweep voltammetry, cyclic voltammetry, and complex impedance spectroscopy. By the addition of the Li202, the electrochemical stability of the electrolyte is improved over 4.0 V (corresponding to the current density below 0.6 mA cm(-2)) and higher specific capacitances at the scan rates of 10-500 mV s(-1) are obtained. Thus, the Li202 can be considered as a promising electrolyte additive to enhance the supercapacitive properties of activated carbon electrode. (C) 2015 Elsevier B.V. All rights reserved.