Deep Eutectic Solvent (DES)-based Electrolytes for Nanomaterials-based Supercapacitors

Current supercapacitors have a very long cycle life, high charge/discharge rates, high specific power, but relatively low specific energy compared to batteries. The theoretical energy and power of supercapacitors is determined by their capacitance, working voltage windows, and conductivities of electrode materials/electrolytes as a function of temperature. With recent advances in nanomaterials-based electrodes, the electrolyte primarily limits the performance of supercapacitors. Organic electrolyte-based supercapacitors are approaching their energy and power limits. Therefore, a safe cost-effective electrolyte with high conductivity and wide voltage windows over wide temperature ranges is needed for next-generation supercapacitors. Lynntech proposes to develop low-cost deep eutectic solvents (DESs) to widen the operational and storage temperature ranges while improving the electrode/electrolyte interface for high energy and high power supercapacitors. During Phase I, Lynntech will develop advanced electrolytes based on appropriate eutectic mixtures utilizing DESs. The ionic conductivity, viscosity, and electrochemical stability will be evaluated over a wide temperature range. A preliminary cell fabrication and testing will be performed. During Phase II, Lynntech will fabricate and evaluate the prototype supercapacitors based on the optimal electrolytes and graphene-based electrodes, and deliver prototypes to the Army for validation. The large scale synthesis of electrolytes and electrode materials will also be explored.