Hydride ion (H⁻), with their low mass and high redox potential, are considered promising charge carriers for next-generation electrochemical devices. However, the lack of efficient electrolyte with fast hydride ion conductivity, thermal stability, and electrode compatibility has hindered their practical applications.
In a study published in Nature, Prof. CHEN Ping's group from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) developed a novel core–shell hydride ion electrolyte, and constructed the the first rechargeable hydride ion prototype battery.
A core-shell structured hydride ion electrolyte and a sandwich structured all-solid-state hydride ion prototype battery (Image by CUI Jirong Cui and ZOU Ren )
Using a heterojunction-inspired design, researchers synthesized a novel core–shell composite hydride, 3CeH3@BaH2, where a thin BaH2 shell encapsulates CeH3. This structure leverages the high hydride ion conductivity of CeH3 and the stability of BaH2, enabling fast hydride ion conduction at room temperature along with high thermal and electrochemical stability.
Furthermore, researchers constructed a CeH2|3CeH3@BaH2|NaAlH4 all-solid-state hydride ion prototype battery using NaAlH4, a classical hydrogen storage material, as the cathode active component. Positive electrode of the battery delivered an initial discharge capacity of 984 mAh/g at room temperature and retained 402 mAh/g after 20 cycles.
In a stacked configuration, the operating voltage reached 1.9 V, powering a yellow light-emitting diode lamp, which was a compelling example for practical applications. This marks that Chinese researchers have developed the first hydride ion prototype battery, achieving a leap from "fundamental concept" to "experimental verification" of hydride ion battery.
By adopting hydrogen as the charge carrier, this technology avoided dendrite formation, paving the way for safe, efficient, and sustainable energy storage. With the tunable properties of hydride-based materials, hydride ion batteries hold immense potential for clean energy storage and conversion.