Theoretical calculations to identify and design transition metal-based additives for hydrogen storage materials

Abstract

This study demonstrates the successful design of transition metal boride-based additives to enhance the hydrogen absorption and desorption kinetics of hydrogen storage materials. Density functional theory (DFT) was used to predict a range of boride compounds, with (Ta:Ti)B2 and (Nb:Ti)B2 identified as promising candidates. In particular, the Nb1/2Ti1/2B2 and Ta1/2Ti1/2B2 compositions significantly improve the kinetic properties of the 2LiH-MgB2 (LiMgB) system. When small amount of these additives is incorporated into LiMgB, its kinetics is improved twice in comparison to the undoped material while maintaining stable reversibility. This substantial improvement is attributed to the presence of Nb1/2Ti1/2B2 and Ta1/2Ti1/2B2 nanoparticles, which act as heterogeneous nucleation sites for MgB2. The study highlights how computational methods can accelerate the design and discovery of optimal additive compositions for hydrogen storage, minimizing the need for extensive experimental testing.