Predicting the stability of aprotic solvents in Li-air batteries: pKa calculations of aliphatic C-H acids in dimethyl sulfoxide

Superoxide is a strong base that can induce base-catalyzed autoxidation of weakly acidic solvents. We report on the performance of several computational protocols for predicting pK(a) values for a wide range of aliphatic C-H acids in DMSO. Calculations at the MP2/CBS level with CCSD(T)/aug-cc-pVDZ corrections and solvent effects calculated using the SVPE model provide the best overall performance (rms deviation is 0.65 pK(a)). The B3LYP, M06, and M06-2X functionals can also achieve high accuracy (<1 pK(a)) by employing empirical corrections to fit the experimental data. Computational results provide a convenient means of screening for suitable solvents in Li-air batteries. (C) 2013 Elsevier B.V. All rights reserved.