High current density, efficient cycling of Zn ~(2+) in 1-ethyl-3-methylimidazolium dicyanamide ionic liquid: The effect of Zn ~(2+) salt and water concentration

摘要

The electrodeposition and dissolution of Zn ~(2+) have been investigated in 1-ethyl-3-methylimidazolium dicyanamide [emim][dca] ionic liquid to support the development of Zn-based secondary batteries. Cyclic voltammetry indicates that the zinc salt dissolved in the ionic liquid (IL) is a critical factor in the observed Zn/Zn ~(2+) electrochemistry. The Zn ~(2+) salt anions were found to have varying interaction strengths with the dissolved Zn ~(2+) species in the order dicyanamide > sulfate > chloride > acetate. The concentration of water was found to be a crucial parameter for obtaining a uniform, dendrite free morphology when depositing zinc at a potential of - 2.15 V vs. Fc ~(0/+). When deposited on glassy carbon, Zn(dca) _2 in [emim][dca] displays high current densities and efficiencies appropriate for use in energy storage applications and has been found to allow the deposition of zinc metal in uniform, non-dendritic morphologies.