High Voltage Electrolyte for Lithium-Ion Cells

For plug-in hybrid electric vehicles (PHEVs) to become commercially viable, the energy content of their batteries must be increased and battery cost must be decreased. This project will develop an electrolyte that will allow lithium-ion cells for PHEV and HEV batteries to operate at higher voltage. At higher voltage, the batteries would be able to deliver higher power and energy. In Phase I, the feasibility of the high voltage electrolyte was demonstrated by improved cycling of high voltage lithium-ion cells and by increased oxidative and thermal stability. In Phase II, the electrolyte formulation(s) will be optimized, and selected combinations of cathode material and novel electrolyte formulation will be tested for pulse power capability. An electrolyte and cathode chemistry will be selected for assembly in graphitic carbon anode lithium-ion cells, which will be tested for performance and stability, and compared to control cells built with standard electrolyte. Commercial Applications and other Benefits as described by the awardee: Improved lithium-ion batteries would have the potential to extend the electric-vehicle range of PHEVs and HEVs while also reducing battery mass and size. These improvements would increase both the environmental benefits and the consumer appeal of these vehicles.