ATTACHMENT: Profile of the Group A Recipient of 2011 C&C Prize
Dr. Akira Yoshino
1970 Earned B.S. from Department of Petro-chemistry, Faculty of Engineering,
1972 Earned M.S. from Department of Petro-chemistry, Graduate School of
1982 Entered Kawasaki Laboratory, Asahi Kasei Corp.
1992 Became Manager, Product Development Group, Ion Battery Business
1994 Became Manager, Technical Development, A&T Battery Corp.
1997 Became Manager, Rechargeable Ion Battery Dept., Asahi Kasei Corp.
2001 Became Manager, Battery Materials Business Development Dept.,
2003 Appointed Fellow, Asahi Kasei Corp.
2005 Earned Dr. Eng. degree from Graduate School of Engineering, Osaka University
2005 Became General Manager, Yoshino Laboratory, Asahi Kasei Corp.
2009 Became General Manager, Battery Materials Business Development Dept.,
2010 Appointed president of Lithium Ion Battery Technology and Evaluation Center
2011 Appointed Adjunct Professor of Graduate School of Engineering,
1999 Fiscal 1998 Chemical Technology Prize (Chemical Society of Japan)
1999 Battery Division Technology Award (The Electrochemical Society)
2001 Ichimura Prizes in Industry-Meritorious Achievement Prize (Ichimura
2001 Kanto-block Commendation for Invention—Encouragement Prize of
2002 National Commendation for Invention—Invention Prize of MEXT (JIII)
2003 Commendation for Science and Technology by MEXT—Prize in
Science and Technology, Development Category (MEXT)
2004 Medal with Purple Ribbon (Government of Japan)
2011 Yamazaki-Teiichi Prize (Foundation for Promotion of Material Science
*MEXT: Japan’s Ministry of Education, Culture, Sports, Science and Technology
**JIII: Japan Institute of Invention and Innovation
<Achievement> In the early 1980s, many researchers and organizations began working hard for over a
decade to develop and commercialize the re-chargeable (secondary) lithium-ion battery
(LIB). These efforts resulted in the high-power, small LIBs used today in mobile and
personal information devices and audio-video equipment. Among the many researchers who
worked on the LIB, Dr. Akira Yoshino played a central role in the development and
Dr. Yoshino started his research on LIBs in 1981. The most important development at that
time was finding suitable materials for both positive and negative electrodes. Dr. Yoshino
started to develop the negative electrode first.
Although attempts had been made to convert the primary metallic lithium battery into a
secondary battery, even the best efforts did not succeed for three main reasons. While
charging, lithium tended to leave deposits on the negative electrode in the form of dendrites,
which easily caused short-circuiting. And the high chemical reactivity of metallic lithium
resulted in poor battery characteristics, including inadequate cycle durability due to side
reactions. Moreover, that chemical reactivity posed an insurmountable problem in terms of
safety due to the inherent risk of a thermal runaway reaction.
Dr. Yoshino conceived the idea of a new secondary battery using electroconductive
polyacetylene as the negative electrode and LiCoO2 as the positive one. The electroconductive polyacetylene had been developed by Prof. Hideki Shirakawa at Tsukuba
University, a Nobel prize winner in 2000. The LiCoO2 was first reported by Dr. J.B. Goodenough in 1980, and was found to be solely applicable to positive electrode material at
that time. Dr. Yoshino confirmed the principle of this new secondary battery with an
operational model in a sealed glass test tube in a non-aqueous electrolyte. His test-tube cell
functioned with the same cell reaction and operating principles of the LIB as it exists today.
It was the world’s first use of an LIB in a non-aqueous electrolyte showing high
electromotive force of around 4 V. Although this cell was functional, the low real density of
the polyacetylene placed limitations on the available capacity, and the chemical stability of
Dr. Yoshino thus searched for a new carbonaceous material to use as the negative electrode.
Although graphite had been studied as a negative electrode material, it was known at that
time that propylene carbonate, which was then a common organic electrolyte, would
decompose during charging when graphite was used. Moreover, the use of a solid
electrolyte resulted in electrical resistance that was too high to enable practical charging and
discharging. Dr. Yoshino therefore studied the suitability of several carbonaceous materials
as the negative electrode. He found that carbonaceous material with a certain crystalline
structure provided greater capacity without causing the decomposition of the propylene
carbonate electrolyte solvent that the graphite did. The secondary battery that he
successfully fabricated in 1985 based on this new combination of component materials
enabled stable charging and discharging over many cycles for a long period for the first time
His combination of electrode materials and cell reaction principles gave the LIB the
a) The avoidance of problems stemming from the high chemical reactivity of metallic
lithium, which had inhibited the practical development of a non-aqueous electrolyte
secondary battery using metallic lithium for the negative electrode.
b) The supply of lithium ions from the LiCoO2 of the positive electrode to the
carbonaceous material of the negative electrode, which marked a new concept for a
secondary battery based on the transfer of lithium ions.
c) The achievement of an electromotive force of 4 V or more and a substantial
improvement in energy density with the use of a non-aqueous electrolyte, which enabled a
significant reduction in the size and weight of the secondary battery.
d) The utilization of a cell reaction without chemical transformation, which provided stable
battery characteristics over a long service life, including excellent cycle durability with little
degradation due to side reactions and excellent storage characteristics.
Dr. Yoshino also devised the other constituent technologies essential for achieving a
practical LIB. His selection of aluminum as the positive electrode’s current collector
material was one of the most important aspects. Previously, only precious metals such as
gold and platinum were considered able to withstand high voltages of 4 V or more.
However, Dr. Yoshino found that aluminum foil was suitable for use as the positive
electrode’s current collector material because a passivation layer forms on the aluminum
Dr. Yoshino’s invention of a highly functional membrane separator was also a particularly
important factor in achieving the safety required for successful LIB commercialization. The
use of a micro-porous polyethylene membrane 20 to 30 microns thick for use as the
separator provided a “fuse” function in which the material of the separator melted to close
the micro-pores and turn off battery operation in the case of abnormal heat generation.
As stated above, Dr. Yoshino played an extremely important role in developing and
commercializing LIBs in the 1980s. His inventions are still used in LIBs today. And, to put
it another way, LIBs could not exist today without Dr. Yoshino’s inventions. The NEC
C&C Foundation thus highly praises Dr. Yoshino for his contributions to the advancement
of the information technology industry through the development and commercialization of
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