Hokkaido University Research Profiles

Manufacturing Technology

Use of Lignin, a Wood Component, as an Electronic Device Material

Molding of lignin and its conversion to a functional material

Lignin is second only to cellulose in availability, but the only way to effectively use lignin at present is to burn it for energy production. We are currently working on molding lignin into fibers and films for use as electrodes and separators in electric double-layer capacitors (EDLCs).

Content of research

EDLCs are electronic devices that are attracting attention as next-generation storage batteries that can replace rechargeable batteries such as Li-ion batteries. The parts called electrodes and separators in EDLCs are made from polymeric materials, so we are conducting research on replacing these polymers with lignin, a major component of woody biomass. By forming lignin into microfibers through electrospinning and converting them into active carbon fibers, we have succeeded in producing the large surface area required for electrode materials. This has led to the production of electrodes with high energy and power densities. In addition, by converting lignin into a flexible polyester film, it became possible to prepare a material that exhibits the same performance as conventional separators. We are currently endeavoring to further improve the performance.

  • Activated carbon fibers for electrodes prepared from lignin electrospun fibers

  • Stacked electrodes made from lignin (high capacity, high output)

  • Polyester film of lignin used as a separator (flexible enough to make origami)

Potential for social implementation

  • ・EDLC
  • ・Carbon electrode for various batteries
  • ・Adsorbent (as activated carbon fiber)
  • ・Insulating film

Appealing points to industry and local governments

In recent years, various kinds of lignins with different properties have been produced industrially. We hope to contribute to the construction of a recycling-oriented society based on renewable resources through the development of specialized applications of specific lignins and water-soluble derivatives that can be prepared from any lignin.