In this paper, K2FeO4 cathodes were coated with tetraphenylporphyrin (TPP) to improve their stability. Analyses involving a scanning electron microscope (SEM), an energy dispersive spectrometer (EDS) and Fourier transform infrared spectroscopy (FT-IR) indicated that the K2FeO4 cathodes were successfully coated with the TPP overlayer. Discharge performance tests were conducted after soaking the cathodes in a 10 M KOH electrolyte for 0-6 h. The discharge properties of the 8 wt%TPP coated K2FeO4 cathodes indicated that they were stable, and their discharge capacity increased to 160 mAh g(-1), from 75 mAh g(-1) for the uncoated electrodes after soaking in a 10 M KOH electrolyte solution for 6 h. In addition, adding 5 wt% sodium bismuthate (NaBiO3) to the tetraphenylporphyrin coated K2FeO4 electrode can further improve its discharge performance by increasing the discharge capacity from 275 mAh g(-1) to 316 mAh g(-1). (C) 2012 Elsevier Ltd. All rights reserved.