Metal-decorated Tri-graphene as a high-performance reversible hydrogen storage medium: A first-principles study

Due to a series of problems caused by the energy crisis, the development of safe and efficient new hydrogen storage materials has become the top priority of current research. In this work, based on the experimental preparation of T‑carbon (Zhang et al. Nat Commun 8, 683 (2017)) material, the [110] surface Tri-graphene (Tri-G) was intercepted. The first-principles method was used to study the hydrogen storage properties of Tri-G and metal-decorated Tri-G. The basic structure and stability of Tri-G are studied systematically, and the electronic properties of Tri-G and metal-decorated Tri-G are calculated respectively. Next, Tri-G is decorated with lithium (Li), sodium (Na), potassium (K), and calcium (Ca). Finally, H2 molecules are attached to each of these bases. The results showed that Tri-G and K@Tri-G could not stably adsorb hydrogen, while Li@Tri-G, Na@Tri-G and Ca@Tri-G could adsorb 24, 14 and 24 hydrogen molecules, and their hydrogen storage rates reached 13.99 wt%, 8.26 wt% and 12.77 wt%, respectively. Moreover, it can be seen that the desorption temperature of H2 is in the range of 255.55 K–281.11 K under the actual conditions of simulated temperature and pressure by Van't Hoff equation, which proves that Li/Na/Ca@Tri-G is an efficient and reversible hydrogen storage material. This study provides theoretical guidance for further expanding the application of carbon-based materials in the field of hydrogen storage.