Hybrid-electrolytes metal-air batteries

Abstract

<p>Single-electrolyte metal-air batteries still have some unsolved problems, such as the limited conductivity of organic Li-air and Na-air batteries, and the limited voltage output of aqueous Al-air, Zn-air, and Mg-air batteries. To tackle this, hybrid electrolytes with different reaction environments on different electrode sides have been proposed, including the “organic-aqueous” and the “acid-alkaline” configuration. The former case protects the Li and Na anode from corrosion while improving the oxygen reaction kinetics, which also has improved discharge stability due to the better dissolution of reaction products in an aqueous electrolyte. However, the current density and cycling lifetime are still limited at the moment. The latter case utilizes the Nernst Equation to change the equilibrium potential of different electrodes, leading to improved voltage and power output for the Al-air, Zn-air, and Mg-air batteries. Nevertheless, the long-term durability of the dual-pH system is still the major obstacle to its practical application. In the future, more advanced electrode/electrolyte materials and battery structures should be developed to break these limitations, while other novel hybrid-electrolyte configurations are also worth investigating.<br></p>