ScholarWorks@성균관대학교

초록

Rechargeable zinc-air batteries are promising candidates for next-generation energy storage systems due to their high theoretical energy density, cost-effectiveness, and environmental compatibility. However, conventional aqueous alkaline electrolytes suffer from drawbacks, including hydrogen evolution, electrode corrosion, and limited electrochemical windows, hindering their long-term stability and application. We report a zinc-air flow battery using a non-aqueous acetonitrile (ACN)-based electrolyte with Zn(ClO4)2 salt. The low viscosity and moderate dielectric constant of ACN promote fast Zn2+ transport and facile desolvation, while spectroscopic analyses reveal strong Zn2+-ACN interactions forming a stable solvation structure. The dendritic Zn anode and carbon-based air cathode enhance interfacial kinetics, enabling reversible Zn plating/stripping and oxygen electrochemistry. In coin-cell tests, the Zn(ClO4)2-ACN electrolyte shows a low polarization gap (Delta V approximate to 0.92 V at 0.1 mA cm-2) and durable cycling over 360 h. A Flow-cell architecture allows evaluation under high-current and application-relevant conditions. The optimized flow battery delivers a peak power density of 53.3 mW cm-2 and stable operation for 200 h with a nearly ideal coulombic efficiency. These results demonstrate that ACN-based organic electrolytes can overcome the limitations of aqueous systems, offering a scalable pathway for developing practical Zn-air flow batteries with ACN-based organic electrolytes.

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