Tri-Electrolyte Aluminum/Air Cell with High Stability and Voltage Beyond 2.2 V

Abstract Aluminum/air battery with remarkably high theoretical energy density is a promising candidate for the increasingly diverse applications in modern society. However, the self-corrosion of Al is one great challenge and limits the practical operating voltage around 1.2 to 1.6 V. Here, a tri-electrolyte aluminum/air cell (TEAAC) is firstly developed to integrate polymer ion-exchange membranes, organic electrolyte, alkaline anolyte, and acidic catholyte, reaching an open-circuit voltage of 2.2 V, which is among the highest reported value for Al/air cells. The adoption of organic alkaline anolyte maintains fairly-good electrochemical activity of aluminum while significantly suppresses the self-corrosion reaction. The acid-base neutralization is avoided with the proper arrangement of two ion-selective membranes. The TEAAC demonstrates stable and robust performance through long-time discharge tests and shows good mechanical rechargeability. The new cell design also allows to use low-cost commercial grade aluminum. This work provides an alternative route for cost-effective and reliable Al/Air battery system.