Research Result

The lithium-ion battery (LIB) has become ubiquitous in our daily lives. The inventor of the LIB is Dr. Akira Yoshino, Honorary Fellow of Asahi Kasei.

Research leading to the LIB started in 1981, when Dr. Yoshino began studying polyacetylene, an electroconductive polymer discovered by Dr. Hideki Shirakawa, Nobel Laureate in Chemistry in 2000. Dr. Yoshino found that polyacetylene could be used as electrode material for a rechargeable battery, and focused on studying it as a negative electrode. At the time, metallic lithium was generally used as negative electrode in efforts to develop a new rechargeable battery. But metallic lithium had many problems, and could not be successfully commercialized. In 1985 Dr. Yoshino changed the negative electrode material from polyacetylene to carbonaceous material, which he used in combination with lithium cobalt oxide (LiCoO2) as positive electrode material. This marked the birth of the basic configuration of the LIB.

The LIB was commercialized in 1991 by Sony and in 1992 by a joint venture between Asahi Kasei and Toshiba. With higher voltage and much larger capacity than other rechargeable batteries, the LIB quickly became widespread. It is now used in smartphones, electric vehicles, and energy storage systems, as well as a growing range of new applications.