Li-ion is a relatively new battery technology that has been commercialized within the past 10 years for many consumer products, but especially for portable power. Li-ion operates by using a different principle to other battery technologies. This principle is called intercalation. Recently, work has been undertaken to explore the high power capability of this technology. The results indicate that present products can provide very high rate capability. Investigations are underway to improve this capability in anticipation of needs for defense and other advanced applications that will require compact high power sources (CHPS).