Enhanced Hydrogen Storage Capacity in Two-Dimensional Fullerene Networks

In contrast to isolated C₆₀ molecular dispersion in solvents, the monolayer C₆₀ networks synthesized by Hou et al. (Nature 2022, 606, 507-510) feature compact nanocages, serving as natural containers for hydrogen storage. The anisotropic lattice and intrinsic local strains induce delocalization of conjugated π orbitals within C₆₀, enabling hydrogen chemisorption without an additional chemical modification. Through first-principles calculations and molecular dynamics simulations, we reveal the correspondence between chemisorption sites and orbital distributions, determining the orientation of polyhedrons formed by physiosorbed hydrogen molecules. The combination of chemisorption and physisorption processes significantly enhances hydrogen storage capacity in monolayer C₆₀ networks while maintaining the thermodynamic stability of the nanocage structures. Numerical results indicate a maximum internal hydrogen pressure exceeding 116 GPa at room temperature and atmospheric pressure. These findings suggest that monolayer C₆₀ networks are promising solid-state candidates for highly efficient hydrogen storage.