Lithium-functionalized boron phosphide nanotubes (BPNTs) as an efficient hydrogen storage carrier

• Published in: International journal of hydrogen energy 2021-06, Vol.46 (39), p.20586-20593
• Main Authors: Cardoso, Günther Luft, Piquini, Paulo Cesar, Khossossi, Nabil, Ahuja, Rajeev
• Format: Article
• Language: English
• Subjects: Boron phosphide; Density functional theory; Hydrogen storage; Nanotubes
• ISSN: 0360-3199; 1879-3487; 1879-3487
• DOI: 10.1016/j.ijhydene.2021.03.146

In this work we have carried out extensive Density Functional Theory (DFT) and ab-initio Molecular Dynamics (AIMD) simulations to study the structural and electronic properties, thermal stability, and the adsorption/desorption processes of hydrogen H2 molecules on Lithium (Li) functionalized one-dimensional boron phosphide nanotubes (BPNTs), for possible use as materials of H2-storage media. Our results show that Li atoms can be adsorbed on the hollow sites of (7,7)-BPNT with binding energy ranging from 1.69 eV, for one Li, to 1.65 eV/Li for 14 Li atoms adsorbed on (7,7)-BPNT. These large energies of Li prevent the formation of clusters on the nanotube sidewall. The investigation of the electronic behavior showed that (7.7)-BPNT semiconductor turns metallic upon the Li-adsorption. Furthermore, the average binding energy of H2-molecules adsorbed on nLi@BPNT(mH2) systems (with n = 1, 2, 4, 6, 8, 14 and m = 1, 2, 3, 4, with m the number of H2 for each Li) lies within a range of 0.13–0.20 eV/H2 which is compatible to the required range for adsorption/desorption of H2-molecules at room conditions. A H2-storage gravimetric capacity up to 4.63% was found for 14Li@BPNT(4H2) system. In addition, AIMD simulation strongly indicates that given adequate monitoring of the temperature, the charge/release process of H2-molecules can be controlled. Our findings suggest that Li-functionalized (7,7) boron phosphide nanotubes can provide a valuable underlying material for H2-storage technologies and therefore must certainly be the subject of further experimental exploration. •DFT calculations on BP nanotube (7,7) (BPNT) - band gap of 1.056 eV.•Li adsorption on BPNT up to 25% coverage. Average bond energy of 1.65 eV.•Up tp 4H2 molecules bound to each Li atom with average bond energy of. 0.13 eV.•A maximum gravimetric capacity is 4.63%, but it can be increased.•MD calculations showed that 76% of the H2 are desorbed for T = 300 K.