High Performance Electrolytes for Electrochemical Capacitors

79591 High performance, long-cycle-life energy storage devices are critical in advanced transportation technologies, e.g., electric vehicles (EV) and hybrid electric vehicles (HEV). Electrochemical capacitors (aka, supercapacitors or ultracapacitors) are being developed as power assists for HEVs. However, a major obstacle in this application limited performance and short lifetimes, determined by the poor properties of currently available electrolytes (including narrow electrochemical window, flammability, toxicity, volatility, thermal instability, and electrolyte depletion). This project will combine the unique properties of environmentally stable ionic liquids (high ionic conductivity, large electrochemical window, excellent thermal and chemical stability, non-volatility, non-flammability, non-toxicity, and negligible electrolyte depletion) with currently well-developed gel polymer electrolyte (GPE) technology to develop novel ionic liquid-incorporated gel polymer electrolytes (ILGPE). Phase I will evaluate commercially available ionic liquids, synthesize and characterize the ILGPEs, and use optimized ILGPEs to fabricate high performance and long-cycle-life electrochemical capacitors. Commercial Applications and other Benefits as described by the awardee: Environmentally friendly and stable ILGPEs should find application in high performance electrochemical capacitors, providing the long cycle life needed for HEVs. Other applications include portable power for consumer, medical, and the military and defense electronics. Moreover, these electrolytes can also benefit a wide range of solid-state electrochemical devices such as batteries, electrochromic devices, sensors, and photoelectrochemical solar cells with extended lifetimes.