Exploration of Alkali‐Metal‐Modified Holey Graphdiyne as a High‐Capacity CH ₄ Fuel Storage System

Efficient CH 4 storage remains a central challenge in enabling large‐scale applications of CH 4 fuel cells. The metal‐modified holey graphdiyne (HGY) CH 4 storage system proposed in this study holds promise as a high‐performance fuel storage unit for fuel cell systems. The CH 4 storage performance of alkali metal‐modified HGY systems is investigated based on density functional theory. The 4Li@HGY system can adsorb 37 CH 4 , achieving a storage capacity of 65.3 wt% with an average adsorption energy of −0.243 eV. Similarly, the 4Na@HGY system adsorbs 41 CH 4 , with a storage capacity of 63.4 wt% and an average adsorption energy of −0.236 eV, both exceeding the U.S. Department of Energy's 50 wt% standard. CH 4 adsorption occurs through interactions with metal atoms, substrate carbon atoms, and other CH 4 molecules, with the metal–CH 4 interaction being the strongest. HGY contains a large pore with a diameter of 10.119 Å, which can accommodate a single CH 4 . This insertion induces special polarization and creates electron‐rich regions on both sides of the substrate plane. The CH 4 thus acts as an attractive bridge, providing adsorption sites for CH 4 around the large pore. In summary, this breakthrough material holds great promise for advancing CH 4 storage technology.