Mapping a stable solvent structure landscape for aprotic Li-air battery organic electrolytes

Electrolyte instability is one of the greatest impediments that must be overcome for the practical development of rechargeable aprotic Li-air batteries. In this work, we establish a comprehensive framework for evaluation of the stability of potential organic electrolytes for aprotic Li-air batteries that is based on four key descriptors: Bond dissociation energy, deprotonation free energy (i.e., Acidity), Nucleophilic substitution free energy, and Electrochemical oxidation/reduction. These parameters were calculated for several classes of organic compounds. The chemical stability of the molecules was studied experimentally under conditions designed to mimic the aprotic Li-air battery environment (heating in the presence of excess KO2 and Li2O2). In general, the calculated and experimental data agreed well for alkanes, alkenes, ethers, aromatics, carbonates, and S-containing and N-containing compounds. Using this dataset, we identified functional groups and other structural features of organic molecules that may be suitable for aprotic Li-air battery electrolyte design.