Prediction of gas solubility in battery formulations

This paper describes the development of a thermodynamic model for predicting solubilities of nine gases (H-2, N-2, CO, Ar, O-2, CH4, C2H4, C2H6, CO2) in battery electrolyte formulations composed of five organic carbonates (cyclic and linear) and lithium salts (LiPF6) between 283 and 363 K and < 1 MPa. The PSRK equation of state by Holderbaum and Gmehling [Fluid Phase Equilib. 70 (1991) 251-265] was combined with the NRTL expression for activity coefficients [H. Renon, J.M. Prausnitz, AlChE J. 14 (1968) 135-144] and used for correlating available gas solubility data. The prediction ability of the PSRK model was tested by correlating gas solubility data in propylene carbonate and predicting the gas Henry's constants in other carbonates. The PSRK predictions of missing combinations and multicomponent systems and were validated by experimental measurements. The PSRK model is shown to predict gas solubilities in ternary battery formulations with accuracy within 10%. The prediction of gas solubility was also tested using the quantum mechanical/COSMO-RS method by Klamt and Eckert [Fluid Phase Equilib. 172 (2000) 43-72]. The COSMO-RS method did not require any prior experimental information and produced quantitatively correct results for binary gas + carbonate systems. (c) 2004 Elsevier B.V. All rights reserved.