DOWA ELECTRONICS MATERIALS Releases Oxide-Based Solid Electrolyte with Globally Best-in-Class Low-Temperature Sintering Property

October 10, 2024
DOWA HOLDINGS CO., LTD.

DOWA ELECTRONICS MATERIALS CO., LTD. (14-1, Sotokanda 4-Chome, Chiyoda-ku, Tokyo; Capital: 1 billion yen; President: SUZUKI Takehiko), a subsidiary of DOWA HOLDINGS CO., LTD. (same location; Capital: 36.4 billion yen; President: SEKIGUCHI Akira) developed garnet-type^*1 solid electrolytes with globally best-in-class low-temperature sintering property for oxide-based all-solid-state lithium-ion batteries (hereinafter all-solid-state batteries) through joint research with the National Institute of Advanced Industrial Science and Technology (hereinafter AIST) and it has released them.
*1: Garnet-type: Electrolyte consisting of a substance that is similar to that of garnet with an [A]₇[B]₃[C]₂O₁₂ crystal structure, where A, B and C represent transition metals or other elements.

All-solid-state batteries differ from lithium-ion batteries (hereinafter liquid-based batteries) in the sense that the electrolyte is solid, not liquid. With a lower risk of ignition, they are very safe and reliable. They have other features such as the potential for increased battery output, capacity and charging speed and the stability of output in low-temperature conditions. They are expected to have practical applications to large batteries, including applications to automobiles and power storage.

There are roughly two different types of solid electrolytes: sulfide-based and oxide-based electrolytes. Since oxide-based electrolytes do not burn, they are safer and more reliable than sulfide-based electrolytes. Among the oxide-based solid electrolytes, garnet-type solid electrolytes are considered to be promising materials that will increase the output and capacity of all-solid-state batteries. However, in the conventional manufacturing process, they must be sintered at a high temperature of at least 1,000 degrees Celsius. This causes other materials to deteriorate.

Recently, AIST and DOWA ELECTRONICS MATERIALS succeeded in creating garnet-type solid electrolyte consisting of fine particles around tens of nanometers in size. Reducing particle diameter results in higher density when compression molding. This means that the electrolyte can be sintered at around 600 degrees Celsius, a lower temperature than conventional garnet-type solid electrolytes. This has opened the way to a battery manufacturing process that limits the deterioration of other materials. It has been confirmed that a prototype all-solid-state battery using the developed solid electrolyte provides sufficient battery performance.
DOWA ELECTRONICS MATERIALS has already commercialized NASICON-type^*2 solid electrolytes. These are being followed by the newly developed electrolytes.
*2: NASICON stands for Na (sodium) Super Ionic Conductor, a substance with an [A]_1＋x[B]_x[C]_2-x(PO₄)₃ composition. DOWA ELECTRONICS MATERIALS has commercialized LAGP solid electrolytes (with a Li_1.5Al_0.5Ge_1.5(PO₄)₃ composition) and other electrolytes.

: 拡大; An all-solid-state battery cell (compression molded and sintered)

The DOWA Group defines the domains of the environment and energy, automobiles, information and communications, and healthcare as growing markets and is actively expanding its businesses in these markets. DOWA ELECTRONICS MATERIALS is working to develop and commercialize materials for batteries to be mainstay products supporting these markets. Aiming to continue to improve the properties of the new recently released oxide-based solid electrolyte products, it is working to develop new products and it will continue to contribute to the practical application and popularization of all-solid-state batteries.

Table: Comparison of lithium-ion battery types