Electrodeposition and stripping of zinc from an ionic liquid polymer gel electrolyte for rechargeable zinc-based batteries

Abstract

In this paper, we report on zinc deposition and stripping in an ionic liquid polymer gel electrolyte on gold and copper substrates, respectively. The ionic liquid-based polymer gel electrolyte is prepared by combining the ionic liquid 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate ([Py1,4]TfO), with Zn(TfO)2 and poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP). The ionic liquid polymer gel electrolyte exhibits good conductivity (2.2 mS cm−1) and good mechanical stability. Zinc deposition and stripping in the ionic liquid polymer gel electrolyte were studied by cyclic voltammetry, potentiostatic, and galvanostatic cycling (charging/discharging) experiments. The gel electrolyte exhibits a promising electrochemical stability and allows a quasi-reversible zinc deposition/stripping. The morphology of the zinc deposits after 10 cycles of zinc deposition/stripping is compact and dense, and deposits without any dendrite formation can be obtained. The quasi-reversibility of the electrochemical deposition/stripping of zinc in this ionic liquid polymer gel electrolyte is of interest for rechargeable zinc-based batteries.