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.