Advances in Fe(VI) charge storage: Part I. Primary alkaline super-iron batteries

Recent advances in super-iron batteries, based on an unusual Fe(VI) cathodic charge storage, are presented. Fe(VI) cathodes that have been demonstrated in super-iron batteries include the synthesized Fe(VI) compound with three-electron cathodic charge capacity Na2FeO4, K2FeO4, Rb2FeO4, Cs2FeO4 (alkali Fe(VI) salts), alkali earth Fe(VI) salts BaFeO4, SrFeO4, and also a transition Fe(VI) salt Ag2FeO4 which exhibits a five-electron cathodic charge storage. This paper focus on the primary alkaline Fe(VI) charge storage in aqueous electrolyte systems. Primary alkaline super-iron batteries exhibit a higher capacity than conventional alkaline batteries. Configuration optimization, enhancement and mediation of Fe(VI) cathode charge transfer of primary Fe(VI) alkaline batteries are summarized. Composite Fe(VI)/Mn(IV or VII), Fe(VI)/Ag(II) and zirconia coating stabilized Fe(VI)/Ag(II) cathode alkaline batteries are also illustrated.