NEWS RELEASE

Teijin Develops Industry's Thinnest Level Gas-diffusion Layerfor Smaller and More Functional Fuel Cells
Tokyo, Japan, March 13, 2023 --- Teijin Limited announced today that it has developed
a gas-diffusion layer (GDL) with a thickness of just 50 micrometers, the industry’s
thinnest level, by combining the company’s ultra-fine fibrous carbon and para-aramid
fiber using proprietary papermaking technology. Teijin expects its new GDL to contributeto the realization of smaller, more functional and lower cost fuel cells, the demand forwhich is expanding.
The GDL is a component used inside a fuel cell to supply hydrogen and oxygen, collectelectrons generated by the chemical reaction of the electrodes, and drain water
generated in the process.
The GDL's microporous structure incorporates Teijin’s PotenCia® fine carbon fiber andTwaron® para-aramid fiber, which are combined in a manufacturing process that has
been sped up by deploying proprietary paper-making technology. PotenCia® enables thenew GDL to achieve excellent conductivity without damaging the catalyst layer inside thefuel cell while Twaron® contributes to high durability and water repellency. As a result, aconventional microporous layer (MPL) is not required, allowing the new GDL to beslimmed down to 50 micrometers, which is less than half the thickness of a conventional
GDL. The new GDL is also expected to reduce production costs by shortening themanufacturing process as well as reducing the number of raw materials required.

50μm

Cross section of Teijin’s new GDLManufacturing conventional GDL (above) and new GDLTeijin is now verifying the GDL's gas diffusion and thermal conductivity, both
indispensable for high performance, and also its contribution to reduced environmentalimpact. Concurrently, Teijin plans to develop new materials that could use the GDL, suchas electrode films, in partnership with other companies that share Teijin's vision forachieving smaller and more functional fuel cells.
Teijin leveraged its extensive experience with fiber-processing technology to develop
PotenCia®, an ultrafine fibrous carbon featuring long fibers and high crystallinity. To takeadvantage of the carbon's thermal conductivity and other special properties, Teijinfocused on the possibility to realizing an extra-thin GDL for fuel cells. GDLs usuallycomprise a conductive fiber sheet made of durable carbon, which is combined with awater-repellent MPL that prevents the accumulation of water but increases the GDL's
thickness, thereby lowering the fuel cell's power performance while adding to themanufacturing cost.
Going forward, Teijin expects to strengthen its development of high-performancematerials and solutions for advanced fuel cell products under the company's long-term
vision of becoming a company that supports the society of the future.
About the Teijin Group
Teijin (TSE: 3401) is a technology-driven global group offering advanced solutions in thefields of environmental value; safety, security and disaster mitigation; and demographic
change and increased health consciousness. Originally established as Japan's firstrayon manufacturer in 1918, Teijin has evolved into a unique enterprise encompassing
three core business domains: high-performance materials including aramid, carbon
fibers and composites, and also resin and plastic processing, films, polyester fibers andproducts converting; healthcare including pharmaceuticals and home healthcare
equipment for bone/joint, respiratory and cardiovascular/metabolic diseases, nursing
care and pre-symptomatic healthcare; and IT including B2B solutions for medical,
corporate and public systems as well as packaged software and B2C online services for
digital entertainment. Deeply committed to its stakeholders, as expressed in the brandstatement “Human Chemistry, Human Solutions,” Teijin aims to be a company thatsupports the society of the future. The group comprises some 170 companies andemploys some 20,000 people across 20 countries worldwide. Teijin posted consolidated
sales of JPY 926.1 billion (USD 7.2 billion) and total assets of JPY 1,207.6 billion (USD9.4 billion) in the fiscal year that ended on March 31, 2022.
Press Contact
Investor and Public Relations Department
Teijin Limited
pr@teijin.co.jp