Perovskite compounds will allow replacing hot organic electrolytes in lithium-ion batteries, which will affect their safety – the combustion factor will practically disappear. The journal Nature Communications writes about it.
Solid material batteries can be safer thanks to the new structural arrangement of atoms. This was done by scientists from the Institute for Integrated Cell and Materials Research (iCeMS) at Kyoto University. They have developed a new type of antiperovskite. This type of compound involves the combination of two types of negatively charged anions and one type of positively charged cations. They also have many interesting properties, including superconductivity and, unlike most materials, heat shrinkage.
Lithium-sodium-rich antiperovskites such as Li3OCl and Na3OCl are attracting the attention of scientists because of their high ionic conductivity and alkali metal concentration, making them a promising alternative to liquid electrolytes used in lithium-ion batteries. “However, achieving a conductivity comparable to that of lithium-ion in solids was a challenge,” explains chemist Hiroshi Kageyama, who led the study.
Kageyama and his team synthesized a new family of lithium and sodium-rich antiperovskites that solved the conductivity problem. Instead of “hard” oxygen and halogen anions, their antiperovskites contain a hydrogen anion called a hydride and “soft” chalcogen anions such as sulfur.
The soft anionic lattice provides an ideal conduction path for lithium and sodium ions, which can be further enhanced by chemical substitution.
The advantages of the new family of antiperovskites seem to be partly due to the ability of the hydride to change its size and expand its compositional space. This helps to stabilize the structure of the joint. In addition, its anomalous vibrational mode contributes to ionic conduction.
“Ultimately, there will be solid-state electrolytes in all-solid-state metal ion batteries for high-performance electric vehicles,” concludes Kageyama.