First principles study of hydrogen storage, electronic, thermodynamic, and mechanical aspects of Perovskite hydrides LiBH₃ (B = Cu, Zn, Cd)

Perovskite hydrides are emerging aspirants for hydrogen (H₂) storage and renewable energy potential. This article comprehensively addresses hydrogen storage capacity, desorption temperature, and physical aspects of LiBH₃ (B=Cu, Zn, Cd) using the WIEN2k code. The mechanical and thermodynamic stability is confirmed by Born mechanical criteria, total energy versus simulation time obtained through ab initio molecular dynamics (AIMD), and formation energy analysis. LiBH₃ compounds exhibit promise for H₂ storage perspectives, showcasing significant gravimetric H₂ storage capacities of 4.12 wt%, 4.02 wt%, and 2.48 wt% for LiCuH₃, LiZnH₃, and LiCdH₃. The temperature of H₂ desorption is 597.7 K, 435.5 K, and 530.9 K, respectively. The thermodynamic parameters elucidate the vibrational characteristics such as entropy, heat capacity, thermal expansion, Debye temperature at lower and higher temperatures, and various pressures. These characteristics further validate the thermodynamic stability of the studied hydrides. Moreover, the band diagram and density of states analysis confirm the metallicity of LiCuH₃ and LiZnH₃, whereas a band gap of 0.21 eV for LiCdH₃ substantiates the semiconductor with a narrow energy gap. These reported intriguing H₂ storage aspects may facilitate the development of effective hydrogen adsorption and release technologies.