New Electrode and Electrolyte Configurations for Lithium-Oxygen Battery

Cathode configurations reported herein are alternative to the most diffused ones for application in lithium-oxygen batteries, using an ionic liquid-based electrolyte. The electrodes employ high surface area conductive carbon as the reaction host, and polytetrafluoroethylene as the binding agent to enhance the oxygen reduction reaction ( ORR)/oxygen evolution reaction ( OER) reversibility. Roll-pressed, self-standing electrodes ( SSEs) and thinner, spray deposited electrodes ( SDEs) are characterized in lithium-oxygen cells using an ionic liquid ( IL) based electrolyte formed by mixing lithium bis(trifluoromethanesulfonyl) imide ( LiTFSI) salt and N,N-diethyl-N-(2-methoxyethyl)-N-methylammonium bis( trifluoromethanesulfonyl) imide ( DEMETFSI). The electrochemical results reveal reversible reactions for both electrode configurations, but improved electrochemical performance for the self-standing electrodes in lithium-oxygen cells. These electrodes show charge/discharge polarizations at 60 degrees C limited to 0.4 V, with capacity up to 1 mAhcm(-2) and energy efficiency of about 88%, while the spray deposited electrodes reveal, under the same conditions, a polarization of 0.6 V and energy efficiency of 80 %. The roll pressed electrode combined with the DEMETFSI-LiTFSI electrolyte and a composite LixSn-C alloy anode forms a full Li-ion oxygen cell showing extremely limited polarization, and remarkable energy efficiency.