The commercialization of rechargeable zinc-air batteries (ZABs) is significantly impeded by their high charging voltage and low energy efficiency. In this work, we apply soluble KI to ZABs as a reaction modifier to change the oxidation pathway in the charging process from oxygen evolution reaction to I- oxidation reaction (IOR), which enjoys lower oxidation potential and faster kinetics. In addition, we surprisingly find that commercial cost-effective XC72R carbon delivers satisfactory bifunctional IOR and oxygen reduction reaction activity. Density functional theory calculation is provided to demonstrate the IOR mechanism by XC72R carbon. Finally, the KI-modified ZABs with XC72R exhibit a low charging voltage of 1.79 V, improved energy efficiency of 65.3% (2.0 V and 60% for conventional ZABs with noble-metal catalysts), and long cycle life of over 120 h at 5 mA cm-2. Further characterizations have illuminated the reason behind the extended battery cycle life as well. This work can significantly facilitate the future use of rechargeable ZABs in energy storage.
|Journal||Energy and Fuels|
|Publication status||Accepted/In press - Dec 2022|
ASJC Scopus subject areas
- Chemical Engineering(all)
- Fuel Technology
- Energy Engineering and Power Technology