Computational Simulations and Strategies for Optimal Hydrogen Storage Materials Design

Abstract

Hydrogen, as the most abundant element in the universe, holds immense potential as the fuel of the future due to its high energy density per unit weight and its environmentally friendly nature. This article offers a comprehensive overview of recent theoretical advancements in hydrogen storage, outlining a general framework for achieving practical hydrogen uptake. We examine the fundamental interaction mechanisms, emphasizing orbital hybridization, polarization induced by external electric fields, and multipole Coulomb interactions between metal atoms and dihydrogen. Special focus is placed on calcium metal, which exhibits a transition from electrostatic to Kubas-type orbital interactions as multiple hydrogen molecules adsorb. The processes of hydrogen dissociation and spillover on sorbent surfaces, catalyzed by metals, are also discussed. We present the formalism by Lee et al. [Phys. Rev. Lett. 97, 056104 (2006)] as a method for calculating maximum hydrogen adsorption per site under varying temperatures and pressures, facilitating estimates of reversible hydrogen delivery. General computational strategies are reviewed, highlighting potential sources of error, such as neglecting zero-point vibrational energies, basis set superposition errors, and inaccuracies due to inappropriate density functionals. Additionally, we address practical challenges in designing optimal hydrogen storage materials for real-world applications, including nanostructure breakdown under intense electric fields, metal clustering, and oxygen blockage of metal functional sites. The article concludes by suggesting strategies to bridge the gap between computational simulations and experimental results, guiding the design of next-generation hydrogen storage materials.