Reversible Li-Oxygen battery based on Liquid Crystal Electrolyte

Abstract

Next generation, high-capacity secondary batteries such as advanced Li-ion, Li-S, and alkali anode based oxygen (metal-oxygen) batteries have been successfully proposed from many different research groups. Among the high capacity secondary battery candidates, metal-oxygen batteries are of interest not only due to their ultra-high capacity based on Li metal anode with light oxygen cathode but also due to their compatibility with battery powered transportation system such as hybrid/electric vehicle. However, previous reports implied that metal-oxygen batteries showed critical limitation because of irreversible electrochemical process during the battery operation. One of the most urgent problems is that metal-oxygen battery formed detrimental Li dendrite on the surface during the discharge-charge process that significantly erodes the cell performance. Here, we investigated newly designed electrolyte using the liquid crystal materials for metal-oxygen battery. This well aligned liquid crystal electrolyte shows retardation of rapid growth of Li dendrite on metal surface, giving rise to a longer cycle life with high Coulombic efficiency in symmetry cell architecture. Furthermore, we successfully demonstrated Liquid crystal electrolyte based Li-O2 battery with OER/ORR ratio of over than 80 % without CO2 evolution.