Gelation of Cathode Electrolytes for Improved Structural Integrity and Enhanced Electrochemical Performance of Li-O_2 Batteries

摘要

Due to the significantly high theoretical energy density, lithium-oxygen (Li-O_2) batteries have been attracting much attention as next generation lithium secondary batteries. Nevertheless, there remain a lot of fundamental challenges to be solved for commercialization of Li-O_2 batteries, and the cycling performance of currently reported state-of-the-art Li-O_2 batteries is still very poor compared to commercially available Li-ion batteries. One of the critical problems for the Li-O_2 batteries is the leakage of excess liquid electrolytes from the cathode. During the cell operation, Li_2O_2 is deposited onto the surface of carbon electrodes, which forces the liquid electrolyte out of the cathode. As a result, the deficiency of liquid electrolytes induces deterioration of the cycling performance. Moreover, the formation of Li_2O_2 causes serious volume expansion of the carbon cathode, which leads to the structural disintegration of electrodes.