Optimized preparation conditions of yttria doped zirconia coatings on potassium ferrate (VI) electrode for alkaline super-iron battery

To enhance the stability of potassium ferrate (VI) (K2FeO4) electrodes and their discharge capabilities in alkaline battery systems, yttria (Y2O3) doped zirconia (ZrO2) (denoted as Y2O3-ZrO2) coatings are utilized to protect the K2FeO4 electrode in alkaline electrolytes. The preparation conditions of Y2O3-ZrO2 coatings on K2FeO4 electrodes are investigated in detail and the optimum preparation conditions are determined. Results of discharge tests with open module batteries show that the Y2O3-ZrO2 coated K2FeO4 electrode (prepared under the optimum conditions) provides a superior discharge specific capacity than uncoated and ZrO2 coated K2FeO4 electrodes. Alternatively, to further explore the practical application of K2FeO4 electrodes, super-iron coin cells are assembled using a Y2O3-ZrO2 coated K2FeO4 electrode as the cathode and zinc foil as the anode. The discharge specific capacity and discharge specific energy of the coin cell with Y2O3-ZrO2 coated K2FeO4 cathode are 169.8 mA h g(-1), and 201.9 W h kg(-1) respectively, which are superior to the MnO2 coin cell. Therefore, the results indicate that Y2O3-ZrO2 coated K2FeO4 cathode is suitable for practical applications in alkaline battery systems. Consequently, the alkaline super-iron battery is expected to become a novel energy resource system that replaces present primary batteries in various electronic devices. (c) 2012 Elsevier Ltd. All rights reserved.