Application of a conversion electrode based on decomposition derivatives of Ag₄[Fe(CN)₆] for aqueous electrolyte batteries

The lack of stable electrode materials for water-based electrolytes due to the intercalation and conversion reaction mechanisms encourage scientists to design new or renovate existing materials with better cyclability, capacity, and cost-effectiveness. Ag₄[Fe(CN)₆] is a material belonging to the Prussian blue family that can be used, as its other family members, as an electrode material with the intercalation/deintercalation reaction or conversion-type mechanism through Ag oxidation/reduction. However, due to the instability of this material in its dry state, it decomposes to AgCN and a Prussian blue residual complex. A possible reason for Ag₄[Fe(CN)₆] decomposition is discussed. Nevertheless, it is shown that the decomposition products of Ag₄[Fe(CN)₆] have electrochemical activity due to the reversible oxidation/reduction of Ag atoms in water-based electrolytes.