Morphology of the Discharge Product in Non-aqueous Lithium-Oxygen Batteries: Furrowed Toroid Particles Correspond to a Lower Charge Voltage

A type of discharge particle morphology that closely resembles furrowed toroid particles, which are formed at high operating oxygen pressures, was discovered. It was also found that the charge voltage required to decompose furrowed toroid particles was lower than that to decompose toroid-shaped particles. Combined experimental and density functional theory investigations showed that the formation of furrowed toroid particles could be attributed to an increase in the proportion of the intermediate discharge product LiO2, which gravitates toward adsorbing onto the surface of the Li2O2 crystal layers rather than onto the carbon substrate. Moreover, the increased proportion of LiO2 in the discharge product particles was found to improve the effective electrical conductivity, which thereby lowered the charge voltage. The findings suggest that the charge voltage can effectively be reduced and the efficiency of the battery can be improved by creating discharge products in the morphology of furrowed toroid particles.