Thermal batteries are normally constructed using pressed-powder anode, separator, and cathode pellets (discs). However, parts less than 0.010” thick are difficult to press from the starting powders. The use of plasma spraying to deposit thin pyrite films onto a stainless steel substrate was examined as an alternative to pressed-powder cathodes. The electrodes were tested under isothermal conditions and constant-current discharge over a temperature range of 400°C to 550°C using a standard LiSi anode and a separator based on the LiCIKCI eutectic. The plasma-sprayed cathodes were also evaluated in similar 5-cell thermal batteries. Cells and batteries using pressed-powder cathodes were tested under the same conditions for comparative purposes.