Abstract
We present the first demonstration of an ionic liquid electrolyte under a realistic flow environment for applications in redox-flow batteries based on the Zn2+/Zn0 redox couple. An electrolyte mixture containing Zn(dca)2 and 3wt% H2O in 1-ethyl-3-methylimidazolium dicyanamide, [Emim][dca], ionic liquid was used to study the effects of Zn2+ concentration and flow rate on the Zn2+/Zn0 electrochemical performance as well as its impact on the morphology of the Zn deposit. An optimized Zn2+ concentration and flow rate were determined by using an in-house-designed 3D-printed flow-cell prototype. Surface characterization through SEM revealed that both the concentration and flow rate directly impact Zn morphology under flow conditions. The electrolyte mixture with a higher Zn(dca)2 concentration (18mol%) showed favourable results; voltammetry showed higher peak current densities (100mA/cm2 discharge current density) and more positive Zn electrodeposition potentials (-1.33V vs Ag/AgOTf) coupled with higher cycling efficiency (45±3%) compared to those obtained with the lower Zn concentration system (9mol%, -1.44V vs Ag/AgOTf, 48mA/cm2 discharge current density and 33±3% cycling efficiency).
Original language | English |
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Pages (from-to) | 1051-1058 |
Number of pages | 9 |
Journal | ChemElectroChem |
Volume | 4 |
Issue number | 5 |
DOIs | |
Publication status | Published - May 2017 |
Keywords
- Flow conditions
- Flow rate
- Morphology
- Redox flow
- Zinc