Like military applications, medical batteries have stringent safety, high specific energy, moderate specific power, and low affordability requirements. Some industrial and experimental batteries use solid electrolyte due to the potential for increased safety. Thin, lightweight solid electrolytes with low lithium reactivity show promise for safe, stable, high specific energy Li-S batteries. One example of a battery that perform well under various safety tests such as overcharge, shock, and puncture tests are Li-S batteries from OXIS Energy TM with specific energies and specific powers of 300 to 400 Wh kg -1 and 57 to 73 W kg -1 , respectively . A nail penetration test was performed on an OXIS TM Li-S cell and a Lithium Cobalt Oxide (LCO) cell with similar capacities (4000 mAh) . When punctured, the OXIS TM Li-S cell had a small temperature rise of 1.4 • C and retained 98% of its voltage after 1 minute, whereas the LCO cell temperature rose by 300 • C, dropped to 0 V, and began releasing gas into the test chamber. In another test, a 5.56 mm bullet was shot through a fully charged OXIS TM Li-S cell which continued to operate, although at reduced capacity, and showed no fire or observable temperature variation. The cell meets various specifications for short-circuit, overcharge, crush, and shock tests corresponding to one or both of the UN38.3 and IEC62133 safety codes.