Validation of the reaction thermodynamics paths associated with LiK(BH4)2 by detection of metastable reaction paths from first-principles calculations

Abstract

LiK(BH4)2, with a 10.65 wt% H2 capacity, is a promising hydrogen storage candidate material. We describe all the possible metastable paths for three reactant mixtures associated with LiK(BH4)2, using first-principles thermodynamic calculations. However, with the first-principles calculations inherent disadvantage is absent from the vibrational entropy contribution to the prediction of the reaction mechanism, which indicates that the reaction mechanism of the reaction path prediction may not be the most stable. The study focuses on examining the possible metastable paths for the three reactants, using first-principles calculations. The objective of this study is to find the minimum free energy path among all the possible paths of the three reactants mixture. A clear conclusion is that the minimum free energy path predicted from first principles thermodynamic calculations is the most stable reaction paths at an appropriate H2 pressure range for all cases. An additional aim of paper is to assess whether the predicted mechanisms can be unambiguously described under the DFT uncertainty.