Design Principles for Aqueous Na-Ion Battery Cathodes

Here, we develop design rules for aqueous sodium-ion battery cathodes through a comprehensive density functional theory study of the working potential and aqueous stability of known cathode materials. These design rules were applied in a high-throughput screening of Na-ion battery cathode materials for application in aqueous electrolytes. Five promising cathode materials, NASICON-Na3Fe2(PO4)3, Na2FePO4F, Na3FeCO3PO4, alluadite-Na2Fe3(PO4)3, and Na3MnCO3PO4, were identified as hitherto-unexplored aqueous sodium-ion battery cathodes, with high voltage, good capacity, high stability in aqueous environments, and facile Na-ion migration. These findings pave the way for practical cathode development for large-scale energy-storage systems based on aqueous Na-ion battery chemistry.