Overcoming the Barriers of Hydrogen Storage with a Low-Temperature Hydrogen Battery Date: September 19, 2025 Source: Institute of Science Tokyo Publication: Science (DOI: 10.1126/science.adw1996) Authors: Takashi Hirose, Naoki Matsui, Takashi Itoh, Yoyo Hinuma, Kazutaka Ikeda, Kazuma Gotoh, Guangzhong Jiang, Kota Suzuki, Masaaki Hirayama, Ryoji Kanno --- Summary Researchers from the Institute of Science Tokyo have developed a novel solid-state hydrogen battery that operates efficiently at low temperatures around 90°C, significantly overcoming the limitations of prior hydrogen storage technologies that required very high temperatures (above 300°C) or extreme conditions. --- Key Highlights Innovation: Introduction of a solid electrolyte—Ba₀.₅Ca₀.₃₅Na₀.₁₅H₁.₈₅—that conducts hydride ions (H⁻) efficiently at low temperatures. Operating Principle: Anode: Magnesium hydride (MgH₂) stores hydrogen. Cathode: Hydrogen gas (H₂). During charging, hydride ions move through the electrolyte from MgH₂ anode to H₂ cathode and release H₂ gas. During discharging, the reverse happens—H₂ gas converts back to hydride ions moving to form MgH₂, effectively storing hydrogen. Performance: Achieved full theoretical storage capacity of MgH₂ (about 2,030 mAh g⁻¹ or 7.6 wt.% hydrogen). Hydrogen absorption and release is reversible and efficient over repeated cycles. Operates safely and efficiently below 100°C. Material Properties: The electrolyte possesses an anti-α-AgI-type crystal structure facilitating superionic conductivity with an ionic conductivity of 2.1 × 10⁻⁵ S cm⁻¹ at room temperature. Impact: Addresses the challenge of hydrogen storage which typically requires extreme low temperatures (−252.8 °C) and high pressures (350–700 bar). Offers a practical and energy-efficient method to store hydrogen for fuel applications. Potentially paves the way for hydrogen-powered vehicles and clean energy systems, advancing carbon-free industries. --- Challenges Addressed Previous hydrogen storage methods needed either: Extremely high operating temperatures (300–400 °C) for solid-state heat-driven gas release/absorption, causing inefficiency. Electrochemical approaches using liquid electrolytes lacked efficient hydride ion transport, resulting in poor hydrogen capacity. The new solid electrolyte and battery design overcome these by enabling reversible, low-temperature hydrogen storage and release via hydride ion conduction. --- Research Team and Affiliations Research Center for All–Solid–State Battery, Institute of Integrated Research, Institute of Science Tokyo Department of Chemical Science and Engineering, Institute of Science Tokyo National Institute of Advanced Industrial Science and Technology (AIST), Japan Institute of Materials Structure Science (IMSS), High Energy Accelerator Research Organization, Japan Comprehensive Research Organization for Science and Society (CROSS), Japan Center for Nano Materials and Technology (CNMT), Japan Advanced Institute of Science and Technology (JAIST), Japan --- Contact for Further Information Institute Professor Ryoji Kanno Research Center for All–Solid–State Battery Email: kanno.r.ade9@m.isct.ac.jp Assistant Professor Naoki Matsui Research Center for All–Solid–State Battery Email: matsui.n.ee49@m.isct.ac.jp Public Relations Division, Institute of Science Tokyo Tel: +81-3-5734-2975 Email: media@adm.isct.ac.jp --- Related Topics and Resources Research at Science Tokyo Research Laboratories Related