Oxygen reduction and evolution are crucial processes in energy conversion and storage. For example, Li–O2 battery is regarded as a promising energy storage system for future applications. However, its energy efficiency is greatly undermined by the large overpotentials of the discharge (formation of Li2O2) and charge (oxidation of Li2O2) reactions. The traditional strategy of using catalysts increases cost and complexity of the system. Here, I will present our systematic investigation of a K–O2 battery that uses K+ions to capture superoxide (O2–) to form the thermodynamically stable KO2 product. This allows for the battery to operate through the facile one-electron redox process of O2/ O2–. Without the use of catalysts, the battery shows a low discharge/charge potential gap of less than 50 mV at a modest current density. This invention has elegantly solved the kinetic challenge in oxygen reduction/evolution without using any catalysts. I will also discuss the main challenge in a K–O2 battery, which is the side reactions at the K metal electrode. and strategies in enhancing its stability. The progress in electrolyte chemistry for reversible dendrite-free K plating and stripping is of general interest to the emerging potassium secondary batteries.

Superoxide batteries based on one-electron reduction of oxygen

2019 Fall National Meeting

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