Investigations of ionic liquid electrolytes for Li-Air batteries

Ionic liquids are molten salts at room temperature that possess many unique properties1. There has been continued increase of interest in ionic liquids because their properties make them attractive for many applications including electrocatalysts, electrodeposition, biosensors, and electrolytes for ionic and electronic devices, including batteries and capacitors2. Their low volatility, high ionic conductivity, and large electrochemical window make them ideal candidates for next generation electrolytes for primary and secondary lithium batteries. The lithium-O2 battery, with a theoretical specific energy of 5200 Wh/Kg3, ten times as high as Li-ion technology, faces many challenges in development before it can become a practically viable power source. The role of electrolyte is crucial in this system and in particular it is necessary to understand reversible O2 electrochemistry in the electrolyte. Therefore, we have been investigating a series of advanced non-aqueous electrolytes for the Li-O2 battery in our Laboratory at Northeastern University Center for Renewable Energy Technology. Our recent studies on the influence of non-aqueous solvents on the electrochemistry of oxygen in the rechargeable lithium-air battery showed that the solvent and the supporting electrolyte cations in the electrolyte act in concert to influence the nature of reduction products and the rechargeability4.