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2022 (English)In: ACS Applied Nano Materials, E-ISSN 2574-0970, Vol. 5, no 6, p. 7954-7966Article in journal (Refereed) Published
Abstract [en]
Hierarchically porous carbon aerogels (CAs) were synthesized by following a green, facile preparation route involving ice-templating and lyophilization followed by carbonization. For the first time, we report CAs prepared with a cooling rate of 7.5 K/min, demonstrating a very high specific surface area (SSA) of 1260 m2 g–1 without any physical or chemical activation steps, and the electrode prepared using the latter aerogel showed superior electrochemical performance with a specific capacitance of 410 F g–1 at 2 m V s–1 with a cyclic stability of 94% after 4500 charge–discharge cycles. The effects of the ice-templating cooling rate and the solid content of lignin and cellulose nanofibers (CNFs) in the suspension on the structure and electrochemical performance of the CAs were investigated. The ice-templating process and the cooling rate were found to have a large effect on the generation of the nanoporous structure and the specific surface area of carbon aerogels, while the solid content of the lignin-nanocellulose suspension showed negligible effects. When assembled as a supercapacitor (SC), a remarkable specific capacitance of 240 F g–1 at 0.1 A g–1 was achieved. The relaxation time constant for the prepared SC was 1.3 s, which shows the fast response of these SCs. In addition, an energy density of 4.3 Wh kg–1 was also obtained at a power density of 500 W kg–1. Thus, this study opens new perspectives for the preparation of green, environment-friendly, free-standing, high-performance CA electrodes for future energy storage applications.
Place, publisher, year, edition, pages
American Chemical Society (ACS), 2022
Keywords
carbon aerogels, ice-templating, nanoporous structure, supercapacitors, specific capacitance
National Category
Physical Chemistry Organic Chemistry
Research subject
Wood and Bionanocomposites; Fluid Mechanics
Identifiers
urn:nbn:se:ltu:diva-91921 (URN)10.1021/acsanm.2c01033 (DOI)000818569100001 ()2-s2.0-85131872933 (Scopus ID)
Funder
Swedish Research Council, 2018-07152Bio4Energy, Carbon Lignin 2017- 04240Vinnova, 2018-04969
Note
Validerad;2022;Nivå 2;2022-06-27 (sofila);
Funder: the MAX IV Laboratory (prop. 20190363)
2022-06-272022-06-272023-09-05Bibliographically approved