Researchers develop solid electrolyte for hydrogen-based batteries and fuel cells

Japanese researchers say they have developed a solid electrolyte that could improve the safety, efficiency and energy density of hydrogen-based batteries and fuel cells.

The team at the RIKEN Cluster for Pioneering Research in Japan said the solid electrolyte allowed hydride ions to be transported at room temperature. Genki Kobayashi, Lead Researcher, said the group had “achieved a true milestone.”

Experimenting with lanthanum hydrides, the team found at room temperature it was “impossible to have efficient conduction.” However, upon replacing some of the lanthanum with strontium and a small bit of oxygen, the team achieved its breakthrough.

Schematic of a solid-state fuel cell made from the new material and titanium © RIKEN Cluster for Pioneering Research in Japan

Finding they could conduct hydride ions at a high rate, the researchers tested its performance in a solid state fuel cell made from the new material and titanium – varying the amounts of strontium and oxygen.

Eventually, the group observed a 100% of conversion of titanium to titanium hydride – meaning “almost zero” hydride ions were wasted.

“In the short-term, our results provide material design guidelines for hydride ion-conducting solid electrolytes,” said Kobayashi. “In the long-term, we believe this is an inflection point in the development of batteries, fuel cells, and electrolytic cells that operate by using hydrogen.”

Many current hydrogen fuel cells work by allowing hydrogen to pass from one side to the other through a polymer membrane. These systems require water, adding a layer of “complexity and cost” to battery and fuel cell design, which RIKEN said, “limits the practicality of a next-generation hydrogen-based energy economy.”

The team has said the next step in its developments will be to improve performance and create electrode materials that can reversibly absorb and release hydrogen.