The effects of vacuum pyrolysis conditions on wood biochar monoliths for electrochemical capacitor electrodes

• Published in: Journal of materials science Vol. 56; no. 14; pp. 8588 - 8599
• Main Authors: Ma, Yu, Li, Yongsheng, Zeng, Yu-Ping
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.05.2021; Springer; Springer Nature B.V
• Subjects: Activated carbon; Adsorption; Biofuels; Biomass energy; Capacitance; Capacitors; Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Cotton; Crystallography and Scattering Methods; Electrochemical analysis; Electrochemistry; Electrodes; Electronic components industry; Energy Materials; Graphitization; Materials Science; Nitrogen; Polymer Sciences; Porosity; Pyrolysis; Solid Mechanics; X ray photoelectron spectroscopy
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-021-05778-5

Vacuum pyrolysis is mostly employed to extract liquid biofuels from biomass in industry, but the potential application of its by-product (biochar) is seldom studied. The wood biochar monoliths were prepared by pyrolyzing cotton rose stem under vacuum conditions and a common nitrogen atmosphere, respectively. The effects of vacuum conditions on the physicochemical properties of biochar monoliths were investigated by various techniques, such as Raman, FTIR, XPS, TG, BET, CO 2 adsorption and SEM methods. The results showed that the vacuum pyrolysis biochar, in comparison with nitrogen atmospheric pyrolysis biochar, features a higher degree of graphitization, a richer micro-porosity (57.2% vs. 33.9%), and a more reactive surface. The comparison of electrochemical performance suggested that the electrode prepared by vacuum pyrolysis overtakes that by nitrogen atmosphere pyrolysis with a specific capacitance of 161 F g −1 versus 133 F g −1 and an ease ion delivery capacity. Moreover, 125% of initial capacitance was retained over 10000 cycles at 50 mA cm −2 . The vacuum conditions are more favorable for the preparation of biochar as well as the biochar derived activated carbon materials for application as electrodes.