Chinese Scientists Achieve Superionic Hydride Ion Conduction at Ambient Temperatures

Materials that can conduct negatively charged hydrogen atoms in ambient conditions would pave the way for advanced clean energy storage and electrochemical conversion technologies. A research team from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) demonstrated a technique that enables a room-temperature all-solid-state hydride cell by introducing and exploiting defects in the lattice structure of rare earth hydrides.

Their study was published in Nature on April 5.

Hydride ion, with its strong reducibility and high redox potential, shows great promise as a hydrogen and energy carrier. Hydride ion conductors are materials that exhibit excellent conduction of hydride ions under specific conditions. These materials have vast potential for use in energy storage and conversion devices such as secondary batteries, fuel cells, electrochemical conversion cells, membrane reactors, and hydrogen sensors.

But hydride ions have a relatively large size, making it difficult to migrate in the lattice. In addition, it’s easy for electrons to be trapped in the lattice during transmission, resulting in higher electronic conductivity of the material.

“Five years ago, when analyzing the results of an experiment, we found that our material could undergo H-D isotope exchange reaction under mild conditions. This interesting phenomenon gave rise to the establishment of the topic of hydride ions conduction,” said Prof. Chen Ping, study author from DICP.

The researchers effectively suppressed electron conduction of LaHx by decreasing the particle size and distorting the lattice via high-energy ball milling, which involves subjecting the material to high-energy collisions. With fast hydride ion conduction and a high ion transfer number, the deformed LaHx material would enable a hydride ion battery to operate at room temperature or lower.

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Previously, hydride ion conductors were only capable of achieving ultra-fast conduction at approximately 300 degrees Celsius. However, this research has successfully demonstrated ultra-fast conduction within the temperature range of minus 40 to 80 degrees Celsius. This breakthrough opens up a new avenue for the development of hydride ion conductors.

According to Chen, the research team’s goal is to demonstrate a brand new all-solid-state hydride ion battery that is of practical potential.