Introducing the hydride battery

The crisis of carbon-emissions-fueled climate change has sent humankind on a treasure hunt for cleaner sources of energy. Hydrogen, the forerunner among clean fuels, has proven difficult to tame because of the demanding conditions needed for its storage and transport. Now researchers have developed the world’s first solid-state, hydrogen-based battery that is rechargeable and works at room temperature (Nature 2025, DOI: 10.1038/s41586-025-09561-3). The battery delivers electrical current by using hydrogen in the form of hydride ions to mediate power-producing electrochemical reactions.The hydride ion (H–) is a promising tool for exploiting hydrogen as an energy source. “It is a lightweight, highly reactive and polarizable, negatively charged ion,” says Ping Chen, a research group leader at the Dalian Institute of Chemical Physics. Yet the absence of a suitable electrolyte that combines high H– conductivity, minimal electron leakage, thermal stability, and electrode compatibility makes practical application of H– unfeasible, Chen explains.Aiming to bypass that shortcoming, Chen and her team zeroed in on cerium hydride (CeH3) as one of the components of a solid-state electrolyte, the material needed to shuttle hydride ions throughout the battery. CeH3 shows high H– conductivity at room temperature, but the material leaks electrons severely, making it unsuitable as a battery electrolyte.To remedy this problem, the researchers coated the surface of CeH3 with a thin layer of barium hydride (BaH2). That material is a relatively good H– conductor and has a wide bandgap, a property quantifying an energy range over which electrons cannot zip around and conduct electricity.They prepared a