A research group consisting of Associate Professor Hirotomo Nishihara and Professor Takashi Kyotani of the Institute of Scientific and Industrial Research, Tohoku University, Associate Professor Taketoshi Matsumoto and Professor Mitsuru Kobayashi of the Institute of Scientific and Industrial Research, Osaka University has been working on high-performance silicon chips from industrial waste. We have developed a method for recycling into negative material for lithium-ion batteries.

 Lithium-ion batteries are widely used in mobile electronic devices such as smartphones and laptop computers, but in recent years they have also been installed in new models such as hybrid vehicles, electric vehicles, and fuel cell vehicles, and have energy density (storing power). There is a strong demand for further improvement in the amount that can be achieved.

 Silicon wafers (semiconductor substrate materials) that are mass-produced generate almost the same amount of chips (silicon chips [Kiriko]) as the production volume, and are industrial waste.In this research, we found that if this silicon chip is crushed into thin nanoflakes, it can be used as a negative electrode material for lithium-ion batteries with high capacity and long life.Furthermore, this nanoflake-like silicon is compounded with carbon to further improve its performance and life, and it charges and discharges about 3.3 times the capacity (1200 mAh / g) of graphite used in conventional lithium-ion batteries. It was found that it can be maintained even if it is repeated 800 times or more.

 The amount of silicon chips generated worldwide exceeds the global demand for lithium-ion battery negative electrode materials, making it an ideal resource.In addition to using industrial waste as a raw material, a simple method that can process even a large amount of silicon is used for crushing silicon chips into nanoflakes and subsequent compounding with carbon, and for lithium-ion batteries. It is expected to lead to the implementation of.

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The "true value" of each person becomes the "evolution" of Osaka University.To a university that lives in the community and extends to the world

Osaka University is a research-based university with 11 faculties and 23 departments. Since its founding in 1931, with the motto of "living in the region and extending to the world," we have created an outstanding "foundation" and "power" that weaves advanced education and research capabilities, the harmony of faculty and staff, and the weight of tradition and the advantage of Osaka. I have.Taking advantage of these excellent potentials […]

Tohoku University

Create excellent research results that will be the source of innovation, and develop talented human resources who will lead the next generation

Tohoku University has a rich culture and humanity based on the tradition of "research first principle" since its opening, the idea of ​​"opening the door" and the spirit of "respect for practical science", and is a phenomenon of human beings, society and nature. In response to this, human resources with the ability to carry out intellectual exploration with a "scientific mind", demonstrating their expertise in various fields from an international perspective and leading […]

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