Thermal batteries are designed to activate at high temperatures (~500℃), therefore, the electrodes used in these systems are typically made into pellet form using compression molding techniques that do not involve polymer binders. However, the compression molding technique poses limitations in scaling up the electrode area without increasing thickness for high-power properties. Additionally, the tape casting method has been studied as a way to solve with, but too low a loading level is still an obstacle to practical use. This study fabricated a film cathode of high loading level (35.79 mAh·cm^-2) using the tape casting method for these problem. As utilized fabricated cathode, it investigated the influence of electrode thickness and density on electrochemical performance. Furthermore, a film cathode with a larger area but the same amount of active material as the pellet was fabricated, enabling the design of high-power cells with the same energy density. We expect that the fabricated film cathode with a high loading level and scalable area will enable the development of various thermal battery designs.

Powder compaction technology is widely used to prepare thermal battery components. This method, however, is limited by the size, thickness, and geometry of the battery components. This limitation leads to excessive cell capacity, overweight, and higher cost of the pellets, which decreases the specific capacities and delays the activation time of thermal batteries. FeS₂ thin-film cathodes were fabricated by tape-casting technology and analyzed by SEM and EDS in this paper. The residual organic binder of the FeS₂ thin-film cathodes decreased with the temperature of the heat treatment, which improved the specific capacity because of the lower resistance. Specific capacities of the FeS₂ thin-film cathodes decreased because of the higher residual binder and the restrictive reaction of active materials with molten salts as the thickness increased. FeS₂ thin-film cathodes showed much higher specific capacity (1,212.2 As/g) than pellet cathodes (860.7 As/g) at the optimal heat-treatment temperature (230℃).