Researchers at the University of Tokyo’s Institute of Industrial Science have uncovered how crystal symmetry acts as a fundamental switch controlling whether hydrogen atoms move through vanadium via classical hopping or quantum tunneling. The discovery, published in Nature Communications, could guide the design of better hydrogen storage materials for clean energy applications.
Hydrogen is a promising fuel for heavy industry, but storing it safely remains a major challenge. Vanadium alloys can absorb hydrogen up to 3.8 percent of their weight, making them one of the most practical solid-state storage materials. The hydrogen molecules split apart inside the alloy and occupy interstitial spaces in the crystal lattice. Understanding exactly how hydrogen moves through that lattice is key to optimizing absorption and release.
The Tokyo team combined structural measurements of hydrogen’s behavior with quantum mechanical calculations inside vanadium’s crystal lattice. They discovered that hydrogen moves between interstitial sites in two fundamentally different ways depending on the crystal structure. In a highly symmetric crystal lattice, typically at low hydrogen concentrations, hydrogen atoms can quantum tunnel through energy barriers, effectively taking a “quantum shortcut” that bypasses the classical path. When the lattice becomes distorted at higher hydrogen concentrations, that tunneling effect is suppressed, and hydrogen must rely on thermal energy to hop between sites classically.
“Crystal symmetry is the underlying switch that turns quantum behavior on or off,” said Professor Katsuyuki Fukutani, who led the research. “In a symmetric structure, hydrogen finds equivalent pathways that allow it to tunnel between sites. Distort that symmetry, as happens at higher hydrogen concentrations, and tunneling is suppressed.”
The finding gives materials scientists a clear design parameter: control the symmetry of the storage material to either enable or disable quantum tunneling, depending on whether fast absorption or stable storage is the priority. For hydrogen-powered vehicles and industrial energy storage, where both speed of refueling and safety of storage matter, that tuning ability could be critical.
Sources: Scientists crack ‘quantum shortcut’ controlling hydrogen behavior in vanadium (Interesting Engineering, July 15, 2026); Nature Communications (DOI: 10.1038/s41467-026-75020-w)