The high-capacity hydrogen storage of B6Ca2 and B8Ca2 inverse sandwiches

• Published in: International journal of hydrogen energy Vol. 46; no. 47; pp. 24225 - 24232
• Main Authors: Wang, Ying-Jin, Wang, Gui-Lin, Guo, Min-Min, Miao, Chang-Qing, Chen, Hua-Ping, Zhai, Hua-Jin
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 09.07.2021
• Subjects: Ca-doped boron cluster; Density functional theory; Hydrogen storage; Inverse sandwich; Ca-doped boron cluster; Density functional theory; Hydrogen storage; Inverse sandwich
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2021.04.206

The B6Ca2 and B8Ca2 clusters adopt interesting inverse sandwich architectures, featuring a prolate B6 (or perfect B8) ring jammed with two capping Ca atoms. Both clusters show the high thermodynamic stability due to the double (σ and π) electronic delocalization. In present paper, we computationally studied the hydrogen storage of them. The results suggest that each Ca site in B6Ca2 and B8Ca2 clusters could store up six H2, yielding a gravimetric density of 14.2 wt% for B6Ca2 and 12.6 wt% for B8Ca2. The average adsorption energy for H2-adsorbed B6Ca2 and B8Ca2 complexes is within the scope of 0.12–0.15 eV per H2 at wB97XD level, hinting that two clusters could reversibly store and release hydrogen, which is positively confirmed by the Born-Oppenheimer molecular dynamics simulations. Both B6Ca2 and B8Ca2 nanoclusters are feasible hydrogen storage media under the ambient condition. The B6Ca2 and B8Ca2 inverse sandwiches possess high-capacity hydrogen storage and release. Each Ca site can adsorb six H2, yielding a gravimetric density of 14.2 wt% for B6Ca2 and 12.6 wt% for B8Ca2. [Display omitted] •The B6Ca2 and B8Ca2 inverse sandwiches have the high thermostability with the double electronic delocalization.•The B6Ca2 and B8Ca2 inverse sandwiches exhibit the high-capacity hydrogen storage and release.•The gravimetric density is as high as 14.2 wt% for B6Ca2 and 12.6 wt% for B8Ca2.•The Ca-doped boron nanostructure can be used as hydrogen storage material.