The phase relationship in the LiFeO2-LiCoO2-NiO ternary system were determined and used to find compositions that would reduce the resistivity of LiFeO2-containing cathodes to levels low enough for molten carbonate fuel cells. There was no solubility limit in the NiO-LiFeO2 binary system; a continuous solution was formed, Two regions of homogeneity were found in the LiFeO2-LiCoO2 binary, 0 to 13 and 87 to 100 mol % LiCoO2. Similarly, two regions of homogeneity were found in the LiCoO2-NiO binary, 0 to 18 and 94 to 100 mol % LiCoO2. The resistivities of these materials indicate that addition of Ni and Co to the LiFeO2 lattice decreases the resitivity from about 300 Omega cm to about 1 to 10 Omega cm at 650 degrees C, Using both Ni and Co additives together reduces the resistivity of LiFeO2 and its sensitivity to CO2 partial pressure. Cell tests indicate that solid solutions LiFeO2-LiCoO2-NiO system posses electrocatalytic activity. The cell displayed a potential of 0.79 V at 160 mA/cm(2). The data indicate that LiFeO2-LiCoO2-NiO cathodes hold promise for Fuel-cell cathodes.