Toyota and Idemitsu Collaboration: Revolutionizing the Future for Solid-State Batteries

On October 12, 2023, Toyota Motor Corporation (Toyota) announced their partnership with Idemitsu Kosan Co., Ltd. (Idemitsu), Japan’s second-largest oil refiner, in the development and commercialization of all-solid-state batteries (ASSBs) for electric vehicles by 2027-28. With this technology, Toyota expects to achieve their goal of a 740-mile driving range from a single 10-minute charging time.

While Idemitsu is better known for their gas stations in Japan, their research efforts in “elemental technologies” for ASSBs began in 2001, predating Toyota’s venture by five years. Their realization of the limited oil resources early on prompted them to find alternative solutions.

During the oil crisis in the 1970s, oil came to be seen as a finite resource that would one day be exhausted. Some said it would run out within 40 years, so we set about developing alternative energies and materials. We conducted research across a rather broad range of fields, seeking ways to add greater value and use oil effectively. The results can be seen in several businesses today.

President Shunichi Koto

The pivotal shift from liquid electrolytes found in conventional Li-ion batteries to a solid-state medium can drastically improve safety, shorten charging time, and increase driving range due to non-flammable properties, faster kinetics, and higher energy density, respectively.

Source: Charged EV Magazine

This partnership is centered on advancing the capabilities of sulfur-based solid electrolytes. They are intrigued by the material’s flexibility, resulting in adhesive and crack-resistance properties. Sulfur-based solid electrolytes have garnered significant interest due to its potential to address major challenges associated with solid-state electrolytes, such as:

1. Electrolyte-Electrode Contact: Sulfur-based materials usually exhibit a conformable quality that allows them to adapt to the irregularities on an electrode surface. This promotes better physical contact that minimizes the likelihood of gaps or poor connections.
2. Durability Over Long Periods of Cycling: Sulfur-based materials can have flexible matrices, which can accommodate volume changes associated with repeated charge and discharge. Flexibility allows it to withstand significant mechanical stress, contributing to enhanced durability during cycling.
3. Sourcing of Material: The sulfur for the solid electrolytes can be obtained from the by-products generated during the process of petroleum refining, a resource Idemitsu possesses in abundance. Sulfur is considered an impurity during refining and must be extracted to prevent corrosion, protect catalysts, and reduce harmful emissions.  

Source: Toyota Motor Corporation

In order to provide a clearer direction, both companies released a comprehensive three phase plan outlining their objectives leading up to commercialization:

Phase 1: Development of sulfide solid electrolytes and preparation for a large pilot facility.

During phase 1, both companies will work together to manufacture sulfide solid electrolytes, focusing on improving quality, cost, and lead times. The goal is to prepare the material synthesis process for mass production by using Idemistu’s pilot facility.

Phase 2: Mass production using a large pilot facility.

During phase 2, Idemitsu plans to construct and startup a large pilot facility to promote sulfide solid electrolyte manufacturing for mass production. Toyota will begin incorporating the electrolyte in their batteries and electric vehicles to prepare for market launch in 2027-28.

Phase 3: Study of future full-scale mass production.

Based on phase 2, both companies will study future mass production and commercialization.

From this collaborative framework and the combination of Idemitsu’s materials manufacturing technology with Toyota’s battery mass production technology, the entire process of battery manufacturing, from material synthesis to finished batteries, is streamlined. Although the partnership is optimistic, the production for ASSBs at such a large volume implies unknown cost concerns and the hope for a seamless integration of Idemitsu’s material and Toyota’s mass production.

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References:

• Corporation., Toyota Motor. “Idemitsu and Toyota Announce Beginning of Cooperation toward Mass Production of All-Solid-State Batteries for Bevs: Corporate: Global Newsroom.” Toyota Motor Corporation Official Global Website, global.toyota/en/newsroom/corporate/39865919.html.
• J. Lau, R. H. DeBlock, D. M. Butts, D. S. Ashby, C. S. Choi, B. S. Dunn, Adv. Energy Mater. 2018, 8, 1800933. https://doi.org/10.1002/aenm.201800933  
• J. Wu, S. Liu, F. Han, X. Yao, C. Wang, Lithium/Sulfide All-Solid-State Batteries using Sulfide Electrolytes. Adv. Mater. 2021, 33, 2000751. https://doi.org/10.1002/adma.202000751
• Quan Shi and Jianxun Wu, Review on Sulfur Compounds in Petroleum and Its Products: State-of-the-Art and Perspectives, Energy & Fuels. 2021, 35 (18), 14445-14461. https://doi.org/10.1021/acs.energyfuels.1c02229
• Corporation., Toyota Motor. “News｜Idemitsu & Toyota Team up to Create Global Standard for All-Solid-State Batteries｜toyota Times.” TOYOTA TIMES, 8 Nov. 2023, toyotatimes.jp/en/toyota_news/1046.html#index02.
• Writer, Staff. “Toyota, Idemitsu Join Hands to Produce Solid-State EV Batteries.” Nikkei Asia, Nikkei Asia, 19 Oct. 2023, asia.nikkei.com/Business/Automobiles/Toyota-Idemitsu-join-hands-to-produce-solid-state-EV-batteries.