Oxygen is a crucial component in emerging technologies in energy conversion and storage. For example, Li–O2 battery is regarded as one of the most promising energy storage systems 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 parasitic reactions of electrolyte and carbon electrode induced by the high charging potential cause the decay of capacity and limit the battery life. Here, a K–O2 battery is report that uses K+ ions to capture O2- to form the thermodynamically stable KO2 product. This allows for the battery to operate through the 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. In addition, I will report our recent detailed studies of the side reactions that limit the cycle life of the K–O2 battery, and discuss the use of O2-blocking membrane electrolytes to address these challenges. Furterhmore, I will report on a high capacity anode material for use in potassium oxygen and potassium-ion batteries. An antimony-based electrode exhibits a reversible storage capacity of 650 mAh/g (98% of theoretical capacity, 660 mAh/g) corresponding to the formation of a cubic K3Sb alloy. Application of this anode material in the form of a K3Sb-O2 cell displays relatively high operating voltages, low overpotentials, increased safety and interfacial stability, effectively demonstrating its applicability to the field of metal oxygen batteries. Finally, I will discuss the system consideration and its potential for transportation electrification and grid storage.

One electron at a time: Rechargeable K-O2 and K-ion-O2 batteries

251st National Meeting (2016)

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