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| August 2005 |
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Makoto Ue, PhD
General Manager, Battery Materials Laboratory, R&D Division,
Mitsubishi Chemical Group Science and Technology Research Center, Inc. (MCRC) |
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Mitsubishi Chemical is investing in the research and development of lithium-ion battery materials as one of its core businesses to nurture.
Invented in 1991, lithium-ion batteries (LIBs) have rapidly grown into a 450 billion-yen industry in no more than 15 years. The first applications included laptop computers and mobile phones; today hybrid electric vehicles are attracting attention as a third large application for LIBs. In response to the situation, Mitsubishi Chemical launched a project to aggregate its businesses and research programs relating to electrolytes, anodes, cathodes, and separators, which is under the direct control of the President. The project resulted in the establishment of the Battery Materials Department in 1999, which was promoted to a business department in 2003.
The research scientists at MCRC have been active in the research and development in line with the business strategy, which is based on the core competence of the Mitsubishi Chemical Group. When the lithium primary battery was first commercialized in Japan in 1971, Mitsubishi Chemical was the only manufacturer of its electrolyte solvent; gamma-butyrolactone. Since then our electrolyte business has accumulated technology and know-how in this area. Mitsubishi Chemical is, to my knowledge, the only manufacturer that develops the four main components of LIBs such as electrolytes, anodes, cathodes, and separators, and we have been making good use of the synergy of related technologies, resulting in the highest number of patent applications among materials producers. In addition, our long experience in analytical and safety evaluation technologies in chemical plants helps us to develop the materials effectively by understanding what is happening within the battery, because "the battery is a miniature chemical plant".
The four main components of LIBs have been the carbon anode, lithium cobalt oxide cathode, organic electrolyte, and polyolefin separator. However, the volumetric capacity has increased by as much as 2.5 times, approaching the theoretical limit value. This has prompted us to develop alloy-based anode materials in parallel with ultimate high-performance, low-cost graphite. Simultaneously, we are developing the corresponding electrolytes based on our original concept of "Role Assigned Electrolytes"(*). New promising cathode materials have also been identified for automotive application. We would like to introduce a noteworthy example of our efforts; our materials are adopted in the LIB used in the Toyota Vitz idling stop car.
(*) Dr. Ue received the Technology Award of the Battery Division of the Electrochemical Society in October 2004. He describes his concept of "Role Assigned Electrolytes" in his award lecture. |
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