Abstract
The capability of Li-decorated (AlN)n (n = 12, 24, 36) nanocages for hydrogen storage has been studied by using density functional theory (DFT) with the generalized gradient approximation (GGA). It is found that each Al atom is capable of binding one H2 molecule up to a gravimetric density of hydrogen storage of 4.7 wt% with an average binding energy of 0.189, 0.154, and 0.144 eV/H2 in the pristine (AlN)n (n = 12, 24, 36) nanocages, respectively. Further, we find that Li atoms can be preferentially decorated on the top of N atoms in (AlN)n (n = 12, 24, 36) nanocages without clustering, and up to two H2 molecules can bind to each Li atom with an average binding energy of 0.145, 0.154, 0.102 eV/H2 in the Lin(AlN)n (n = 12, 24, 36) nanocages, respectively. Both the polarization of the H2 molecules and the hybridization of the Li-2p orbitals with the H-s orbitals contribute to the H2 adsorption on the Li atoms. Thus, the Li-decorated (AlN)n (n = 12, 24, 36) nanocages can store hydrogen up to 7.7 wt%, approaching the U.S. Department of Energy (DOE) target of 9 wt% by the year 2015, and the average binding energies of H2 molecules lying in the range of 0.1–0.2 eV/H2 are favorable for the reversible hydrogen adsorption/desorption at ambient conditions. It is also pointed out that when allowed to interact with each other, the agglomeration of Li-decorated (AlN)n nanocages would lower the hydrogen storage capacity.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.