Wednesday, 4 October 2017
Prince George's Exhibit Hall D/E (Gaylord National Resort and Convention Center)
Potassium-ion battery (PIB) has recently attracted great attention not only as a low-cost alternative to lithium, but also as a high-voltage contender considering the significantly negative potential of the K+/K redox couple, which is close to or even lower than that of Li+/Li depending on the solvent [1-3]. However, the large ionic radius of potassium limits the number of potassium-based compounds that can practically be utilized as high capacity materials. As shown in Fig. 1, a vast number of polyanion-based frameworks exhibit high voltages, prime among them being vanadium-based compounds (viz., KVPO4F, KCoSO4F, KNiSO4F and KVOPO4 ) that show voltages exceeding 4 V vs. K. Equally important as the high voltage is high capacity, that is difficult to achieve considering the high molecular weight of most of the K-containing polyanion frameworks. This has motivated an impetus to develop high capacity oxide-based cathode materials for PIB. We will highlight potential potassium-rich manganese- and iron-based oxides, while underpinning promising polymorphs of phosphate-and sulphate-based polyanion cathode frameworks.
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