Supercapacitors (also known as ultracapacitors, double-layer capacitors or electrochemical capacitors) are under consideration for a range of applications where high power density and long cycle life are required. This technology enables operation at more extreme temperatures (-40 C to +65 C) relative to other energy storage options such as commercially available lithium-ion cells. There are emerging applications in the aerospace, automotive and energy sectors where even wider temperature limits will be required to support high reliability power needs. Efforts are under way to design supercapacitor cells to operate at -70 C or below, as well as temperatures exceeding +100 C, while still retaining the other desirable attributes of supercapacitors. This talk will focus on current work to develop and screen new wide temperature components (electrodes, electrodes, separators) for operation in these environments, and demonstrating their performance in prototype cells.