Lithium anode primary batteries display numerous outstanding characteristics including high energy density, long shelf life, low self-discharge, and ability to function under a broad temperature operating range. This has led to the design and implementation of lithium primary cells for a variety of applications in the commercial, military, space, and medical fields. The development of these primary batteries has required understanding and resolution of complex reaction mechanisms as well as optimized electrode and cell designs to meet the needs of the target applications. Notably, a variety of cathode materials have been paired with lithium metal anodes including carbon monofluoride (CFx), manganese oxide (MnO₂), thionyl chloride (SOCl₂), and sulfur dioxide (SO₂). A specific application of primary lithium battery systems is to power implantable medical devices. These primary systems utilize lithium metal anodes with cathodes such as iodine, manganese oxide, carbon monofluoride, silver vanadium oxide, and hybrid cathodes. While the specific performance requirements of applications vary, lithium batteries can provide the solutions for single use power source needs.