Defence R&D Canada (DRDC) is investigating lithium-ion polymer cells for possible future use in army communications and soldier systems, because of their high specific energy. Military operation requires good performance at −20°C but the standard commercial lithium-ion polymer cells yield only approximately 30% of their room temperature capacity at this temperature. The standard electrolyte is known to be poorly conducting at −20°C, so DRDC has been working with a Canadian company to produce a cell containing an electrolyte that gives good low temperature performance. Prototype cells have been built and cycled under various conditions. The performance of these cells and the standard cells is discussed.