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BRAGI: Bio-chars for energy harvesting and storage applications

Updated: Aug 28

Biochars produced from biomasses are an emerging type of renewable material that cannot only replace fossil-based coal but also perform as raw materials in high-value applications such as electronics. In the BRAGI project, we aim to develop sustainable and economically feasible methods to process and activate various biomasses into biochars to be used in future energy applications. The developed chars have different morphologies and heteroatoms depending on the used processing method and origin of the biomass. Hence, they can be suitable for a variety of energy application including photovoltaics and supercapacitors.

Main results

  • Hydrothermally carbonized and alkali-activated brewer's spent grain has a microporous structure leading to an extremely high surface area making it a promising candidate for electrochemical applications.

  • A flexible supercapacitor was developed from biowastes, from brewery and animal bone residues, which were assembled as the aluminium-crosslinked cellulose nanocrystal hydrogel and porous carbon components.

  • The flexible supercapacitor displayed high energy density, exceptionally high power density, and ultra-long cycle life. It maintained a high electrochemical performance upon bending, indicating excellent prospects for biowaste-derived materials for next generation renewable flexible energy storage and conversion applications.


  • Tiihonen, A., Siipola, V., Lahtinen, K., Pajari, H., Widsten, P., Tamminen, T., Kallio, T., & Miettunen, K. (2021). Biocarbon from brewery residues as a counter electrode catalyst in dye solar cells. Electrochimica Acta, 368, [137583].

  • Al Haj, Y., Mousavihashemi, S., Robertson, D., Borghei, M., Pääkkönen, T., Rojas, O. J., Kontturi, E., Kallio, T., & Vapaavuori, J. (2022). Biowaste-derived electrode and electrolyte materials for flexible supercapacitors. Chemical Engineering Journal, 435(3), [135058].

Research Project Managers

Tanja Kallio, Aalto

Kati Miettunen, Aalto (currently at University of Turku)

Tommi Virtanen, VTT

Petri Widsten, VTT

Virpi Siipola, VTT

Project status

Funded by FinnCERES 2018-2021.

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