Lithium-thionyl chloride (Li-SOCl₂) batteries are primary (non-rechargeable) batteries known for their high energy density, long shelf life, and wide operating temperature range. They use lithium as the anode and thionyl chloride as both the cathode and electrolyte. These batteries are commonly used in applications requiring reliable, long-lasting power, such as industrial sensors, military equipment, medical devices, and remote monitoring systems.