Japan developed all-solid-state hydrogen anion batteries

Researchers at the Tokyo Institute of Technology are demonstrating for the first time electrochemical reactions based on hydride ions (H-) in oxide-based solid-state cells in hopes of demonstrating their potential to be the foundation of the next generation of cells.

Genki Kobayashi and Ryoji Kanno, faculty members at Tokyo Institute of Technology, as well as experts from the Institute of Molecular Sciences (ISM), Japan Science and Technology Agency (JST), Kyoto University and High Energy Accelerator Research Institute (KEK) researchers deduced that hydride (H-) is expected to be used for high energy density storage devices. Using oxy-hydrogenated solid state cells, the researchers showed for the first time that pure hydrogen anions (H-) can be conducted in oxides.

The lattice of metal hydride is often not flexible enough to make it difficult to transport the hydride (H-), which is why the researchers turned to oxygen hydride - where oxygen and hydrogen share the same lattice position. Another challenge is the high electron-donating properties of hydrogen, which means that electrons will dissociate from the hydride (H-) to produce protons and electrons, resulting in the migration of electrons rather than hydride ions. So the research team had to look for another set of systems that contained cations, where the electron donors were more hydrogen than hydrogen.

The crystal structure of La2-x-ySrx + yLiH1-x + yO3-y (x = 0, y = 0, 1, 2)

The researchers looked at how their oxygen-hydrogen compounds changed in composition and synthesis conditions, and also studied the electronic structure and found that the ionic Li-H bonds in the compounds, that is, the presence of hydronium (H ).

All-solid-state hydrogen anion (H) battery: Solid state battery discharge curve with Ti / o-La2LiHO3 / TiH2 structure. The middle figure shows the battery and its possible electrochemical reaction

Next, the researchers used La 2 LiHO 3 in the orthorhombic phase (o-La 2 LiHO 3) as an electrolyte for a battery (with a titanium anode and a hydride cathode). Since the phase change of the electrode caused by the discharge is in agreement with the phase of Ti-H, the migration of hydride ions is shown. The researchers concluded: "The successful construction of an all-solid-state electrochemical cell with hydrogen anion (H) diffusion not only demonstrates the ability of the oxyhydride as a hydrogen anion (H) solid-state electrode, but it also helps to develop an all- (H) conducting electrochemical solid-state device. "