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The electrochemical reduction of CO 2 to formic acid or formate is a promising process for addressing technological challenges of transporting and storing energy produced by intermittent renewable energy sources. However, this electrochemical CO 2 conversion process requires high overpotentials to activate CO 2 into “an energetically unfavorable” radical anion intermediate on metal electrodes under the aqueous electrolyte systems. For our present study, we introduce a novel solvent additive such as 1-ethyl-3-methylimidazolium dicyanamide ([Emim][N(CN) 2 ]) ionic liquid into the aqueous solution to increase the electrochemical reduction activity of CO 2 for the formic acid formation, to increase the CO 2 solubility, and to suppress the competitive hydrogen evolution reaction. Cyclic voltammetry is performed in an [Emim][N(CN) 2 ] aqueous solution on a Sn powder electrode to determine the onset potential of CO 2 electrolysis and its electrochemical stability. In addition, CO 2 electrolysis is carried out by chronoamperometry measurements at various fixed potentials and electrolyte concentrations to understand their effects on the faradaic efficiency for the conversion of CO 2 into the formic acid. The maximum faradaic efficiency obtained during electrolysis with a 0.5 M concentration of [Emim][N(CN) 2 ] is 81.9% towards the formation of formic acid at −1.2 V vs. RHE and at the overpotential of 1.08 V. [ABSTRACT FROM AUTHOR]