January 29, 2024
NEWS RELEASE

Decision to Invest in 2nd Enhancement of Production Capacity of Mass Production Testing
Facility for A-SOLiD, a Solid Electrolyte for All-Solid-State Batteries
Mitsui Mining & Smelting Co., Ltd. (President: NOU Takeshi) is pleased to announce today that it has
decided to invest in the second enhancement of its production capacity at its mass production testing facilityfor the solid electrolyte for all-solid-state batteries1 which it sees as a promising business, branded as ASOLiD.2
All-solid-state batteries are expected to be the next generation of storage batteries. Efforts to develop them areunderway for a wide range of applications, including electric vehicles (EVs). A-SOLiD was created by battery
material technology cultivated over many years, and we have defined this material for all-solid-state batteries. We
continue to work together with customers and market partners towards the commercialization of these brand-newbatteries.
We are scheduling to finish the first enhancement of production capacity in March. This was reported in the news
release dated February 13, 2023, titled “Mitsui Kinzoku enhances production capacity of A-SOLiD, a solid
electrolyte for all-solid-state batteries, from its mass production testing facility.” Amid the active development raceworking to achieve the commercialization of all-solid-state batteries for EVs and other applications, multiple
customers in Japan and abroad currently have increasing needs for A-SOLiD. We have decided to invest in a second
enhancement of production capacity in the existing building. This will increase the production capacity of the mass
production testing facility to about three times its current level. At the same time, we will further improve the qualityof production by introducing new equipment that enable highly productivity and quality stabilization.
A-SOLiD is so highly regarded by the market for its performance and quality that we have continued to provide
samples to customers and market partners. This second enhancement of production capacity and improving thequality of production are expected to enable a further push for the future development of all-solid-state batteries.
We will continue its endeavors towards the social implementation of all-solid-state batteries through the stablesupply of A-SOLiD.

In accordance with Our Purpose, which states, “We promote the well-being of the world through a spirit ofexploration and diverse technologies,” we are committed to identifying new unique applications for the all-solidstate batteries, including EVs, together with all parties in its endeavors to build a sustainable society.
[Outline of mass production testing building]
Address: In the premises of Corporate R&D Center, Business Creation Sector (1333-2 Haraichi, Ageo-shi,Saitama)[Inquiries]
Corporate Communications Department, Corporate Planning & Control Sector, Mitsui Mining & Smelting Co.,Ltd.
TEL: +81-3-5437-8028 Email: PR@mitsui-kinzoku.com

Glossary
1 All-solid-state batteries
All-solid-state batteries feature high energy density, high I/O performance, high environment resistance andother attributes, and are being developed for applications in special environments and for new power storageand electric vehicle (EV) applications. Some have already entered the practical application phase.

2 A-SOLiD
Our solid electrolyte a high lithium ion conductivity equivalent to that of organic electrolytes and is anargyrodite-type sulfide solid electrolyte, which is electrochemically stable. With this brand, it will contribute to
the popularization of all-solid-state batteries.
(Reference)
February 13, 2023, Mitsui Kinzoku enhances production capacity of A-SOLiD, a solid electrolyte for all-solid-statebatteries, from its mass production testing facility
https://www.mitsuikinzoku.com/LinkClick.aspx?fileticket=vLM5RI33g6Y%3d&tabid=278&mid=824&TabModule1277=1

Photo of argyrodite-type sulfide solid electrolyte (A-SOLiD)

A-SOLiD is produced in this mass production testing building.