Sulfide-based solid electrolytes, a material from Mitsubishi Materials, are expected to be used as a material in all-solid-state batteries for xEVs (electric vehicles). In this issue, we will introduce our unique technology that was developed to mass-produce these materials.

Bonding material for attaching components is necessary in semiconductors. Mitsubishi Materials produces this material using copper powder with extremely small grains measuring only a few nanometers. Copper’s melting point is very high, exceeding 1000°C, but if it’s in the form of a very small, consistently-sized powder, it actually melts at a lower temperature. Thus, creating the material using powder is easier and more cost effective. By melting the powder into a cream like paste, we can form it into various shapes and sizes, allowing us to bond together semiconductors in a variety of shapes. The strength of copper is greatly demonstrated when used in semiconductors.

Sulfide-based solid electrolytes are “transformed” into all-solid-state batteries. Generally, the contents of batteries used for xEVs include flammable fluid, so there is a risk that they combust when something unusual happens. However, all-solid- state batteries, whose contents are solid, aren’t flammable, which reduces the risk of combustion. Additionally, these batteries have better heat and cold resistance compared to batteries that use liquid, enabling us to realize safer and more versa- tile xEVs.