Design of highly conductive iongel soft solid electrolytes for Li-O2 batteries

Li-O2 batteries show high energy storage potential, but there remain many material challenges that must be solved to fully develop them into a robust technology. The reactivity of the electrolyte against lithium metal as the anode or with oxygen superoxide radicals in the cathode is the main problem that may be alleviated by the use of ionic liquids and solid electrolytes. In this work, iongel solid flexible electrolytes with facile preparation are designed based on five variations of the successful N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide ionic liquid. These iongels show an outstanding ionic conductivity of 7.8 x 10-3 S & BULL;cm-1 at 25 & DEG;C, excellent performance against lithium metal and reduced dendritic growth, even at a high current density rate of 2 mA & BULL;cm-2. Tests on Li-O2 cells show a 100% capacity retention for 25 cycles with limited capacity. Hence, this work provides a plausible pathway to tackle the design of effective lithium protection methods and efficient solid electrolytes for Li-O2 batteries.