HIGH-PERFORMANCE LITHIUM-OXYGEN BATTERIES WITH LOW CHARGE OVERPOTENTIALS ENABLED BY ELECTROLYTE ADDITIVES

Abstract

Aprotic Li-O2 batteries (LOBs) with high theoretical energy density are expected to be promising energy storage systems. However, to realize the practical applications, LOBs confront cathode clogging and high charge overpotential by insoluble and insulating Li2O2. In this thesis, we aim to develop electrolyte additives to address these issues comprehensively for high-performance LOBs. Firstly, we investigated the Li+ complexation of a crown ether-based compound. Its strong adsorption ability towards Li+ increases the solubility of Li2O2 and facilitates the generation of discharge products in the solution pathway. In addition, the generated complex adsorbs reactive O2¯ to alleviate parasitic reactions. Secondly, dibenzo-24-crown-8 aldehyde derivative (DB24C8A) was introduced as an effective trifunctional electrolyte additive to boost the performance of LOBs. Lastly, we report a facile introduction of Cl− additives to reduce the charge overpotential through the Cl−/Cl3− redox couple. Moreover, it can modulate discharge products from Li2O2 to LiOH.