A Graphite Intercalation Composite as the Anode for the Potassium-Ion Oxygen Battery in a Concentrated Ether-Based Electrolyte.

Nowadays, alkali metal-oxygen batteries such as Li-, Na-, and K-O2 batteries have been investigated extensively because of their ultrahigh energy density. However, the oxygen crossover of oxygen batteries and the intrinsic drawbacks of the metal anodes (i.e., large volume changes and dendrite issues) have still been unsolved key problems. Here, we demonstrate a novel design of the K-ion oxygen battery using a graphite intercalation composite as the anode in a highly concentrated ether-based electrolyte. Instead of the metal K anode, the potassium graphite intercalation compound as the anode is depotassiated/potassiated in a binary form below 0.3 V (vs. K+/K); correspondingly, the discharged product KO2 is formed/decomposed at the carbon nanotube cathode, and an all-carbon full cell exhibits impressive cycling stability with a working voltage of 2.0 V. Furthermore, the utilization of graphite intercalation chemistry has been demonstrated to be applicable in Li-O2 batteries as well. Therefore, this study may provide a new strategy to resolve the key problems of the alkali metal-oxygen batteries.