Researchers at the Institute of Science, Tokyo, in Japan, have announced a breakthrough in hydrogen storage technology.
The team developed a hydrogen battery that can operate at just 90 °C (194 °F), far below the usual 300–400 °C (572 °F – 752 °F) threshold.
The innovation addresses one of hydrogen’s greatest obstacles – safe and efficient storage – potentially opening doors for hydrogen-powered vehicles, renewable energy integration, and carbon-free industries.
The study was conducted by a team of scientists, including Research Scientist Dr. Takashi Hirose, Assistant Professor Naoki Matsui, and Institute Professor Ryoji Kanno, at the Research Center for All-Solid-State Battery in Science, Tokyo.
Tackling hydrogen storage challenges
Hydrogen has long been championed as a clean energy carrier, but storing it has proven difficult. Conventional methods require either compressing hydrogen at extremely high pressure (350–700 bar) or cooling it into liquid form at cryogenic temperatures of −252.8 °C (-423 °F).
The Science Tokyo researchers overcame these hurdles by developing a hydrogen battery that efficiently stores and releases hydrogen at much lower temperatures.
Solid-state storage using magnesium hydride (MgH₂) offers a promising alternative because of its high theoretical capacity. Yet, until now, MgH₂ systems needed extreme heat to function, with limited reversibility and performance losses. This made them impractical for everyday energy applications.
“We demonstrated the operation of an Mg–H2 battery as a safe and efficient hydrogen energy storage device, achieving high capacity, low temperature, and reversible hydrogen gas absorption and release,” explained Mastui.
A novel solid electrolyte at the core
The key to this innovation lies in a newly engineered solid electrolyte structure that enables rapid movement of hydride ions, with ionic conductivity measured at at room temperature.
Unlike traditional liquid electrolytes, this material provides stability and efficiency at lower operating conditions.
The system’s architecture is straightforward yet powerful. MgH₂ acts as the anode while hydrogen gas serves as the cathode. During charging, MgH₂ releases H⁻ ions that travel through the solid electrolyte and are oxidized at the cathode, releasing H₂ gas. Hydrogen gas is reduced to H⁻during discharge, which migrates to the anode to reform MgH₂.
This fully reversible cycle enables the device to repeatedly store and release hydrogen without the extreme heat required in conventional systems.
Implications for a hydrogen economy
In tests, the hydrogen battery achieved the full theoretical storage capacity of MgH₂: approximately 2,030 mAh g⁻¹, equivalent to 7.6 wt.% hydrogen. This milestone has never been reached with practical, low-temperature operation.
“These properties of our hydrogen storage battery were previously unattainable through conventional thermal methods or liquid electrolytes, offering a foundation for efficient hydrogen storage systems suitable for use as energy carriers,” Hirose explained.
The implications of this experiment extend far beyond the lab. Hydrogen is considered the cornerstone of clean energy, and this breakthrough could accelerate the rollout of hydrogen-powered vehicles, industrial applications, and renewable storage solutions.