Chemical synthesis of battery grade super-iron barium and potassium Fe(VI) ferrate compounds

The chemical preparation of high purity potassium and barium ferrates for alkaline electrochemical storage are presented. The synthesized salts are used to demonstrate a variety of high capacity super-iron (Zn anode) alkaline AAA cell configurations which utilize these Fe(V) salts. Results of 500 days, full stability, of the synthesized K2FeO4 are presented. Synthetic pathways yielding 80-100 g of 96.5-99.5% pure K2FeO4 and BaFeO4 are presented, and the products of these syntheses are demonstrated to provide a high energy electrochemical discharge in a variety of AAA alkaline cells. BaFeO4 super-iron alkaline AAA cells provide over 0.8 W h during 2.8 Omega discharge, yielding over 200% higher capacity than conventional alkaline batteries. The barium super-iron cell configurations studied provide higher capacity than the potassium super-iron alkaline cell configurations studied. (C) 2001 Elsevier Science B.V. All rights reserved.