Hydrogen Storage Materials Based on Single-Layer Aluminum Nitride Nanostructures

Using the first-principles method based on density functional theory, we study the hydrogen storage properties of Li-doped single-layer aluminum nitride nanostructures (AlN). For the pristine AlN sheet, each Al atom adsorbs one H2 with an average binding energy of 0.14 eV/H2. The hydrogen blinding energies and storage capacities can be markedly increased by doping Li atoms onto the AlN sheet. The charge analysis shows that there are charges transferring from the Li atoms to the AlN sheet, thus the charged Li atoms can polarize hydrogen molecules and enhance the interaction between hydrogen molecules and the AlN sheet. In the fully loaded cases, the Li-doped AlN sheet can contain up to 8.25wt% of molecular hydrogen with an average binding energy of 0.20 eV/H2.