In a new study, scientists at the Tokyo Institute of Technology used two lithium-based solid electrolyte chemical compositions to ensure stable ionic movement in millimeter-thick battery electrodes.

Solid electrolytes are much stabler compared to liquid electrolytes. Argyrodite-type (Li6PS5CI) and Tetragonal Li 10 GeP 2 S 12, abbreviated as LGPS, are the two compositions used by Ryoji Kanno of the institute to increase the complexity of the superionic crystals.

The study published in Science highlights that compared to liquid electrolytes conventionally used in commercial batteries, solid electrolytes are less prone to overheating, fire, and loss of charge, ultimately degrading the battery’s performance over time.

However, the scientists found that the tough structure of solid electrolytes leads to wetting of the cathode in the battery, limiting the supply of lithium ions to the cathode.

The researchers used a multi-substitution method and modified the LGPS type while synthesizing a series of crystals with a composition of a lithium-ion conductor with a garnet-like structure that is being studied for its potential use in all-solid-state batteries.

The area-specific capacities were 1.8 and 5.3 times larger for the values obtained compared to the discharge capacities attained in all solid-state lithium batteries in previous experiments.

Kanno said, “In effect, the proposed design rule lays a solid groundwork for exploring new superionic conductors with superior charge–discharge performance, even at room temperature. Many studies have shown that inorganic ionic conductors tend to show better ion conductivity after multi-element substitution probably because of the flattened potential barrier of Li-ion migration, which is essential for better ion conductivity.”

Another study by the United States’ Lawrence Berkeley National Laboratory reported that solid-state batteries with the disordered arrangement of metals in electrolytes improve the battery’s performance by increasing the flow of ions, which creates an electrical charge.

In a similar experiment, researchers from Purdue University engineered a new composite solid-electrolyte by introducing a new material that they claimed provides thermal stability to solid-state lithium-ion batteries, which achieves higher energy density.