Hydrogen-Assisted Thermal Treatment of Electrode Materials for Electrochemical Double-Layer Capacitors

• Published in: ACS applied materials & interfaces 2024-03, Vol.16 (11), p.13706-13718
• Main Authors: Gentile, Matteo, Bellani, Sebastiano, Zappia, Marilena I., Gamberini, Agnese, Mastronardi, Valentina, Abruzzese, Matteo, Gabatel, Luca, Pasquale, Lea, Marras, Sergio, Bagheri, Ahmad, Beydaghi, Hossein, Papadopoulou, Evie L., Lanzani, Guglielmo, Bonaccorso, Francesco
• Format: Article
• Language: English
• Subjects: Energy, Environmental, and Catalysis Applications
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.3c18629

The capacitance of electrode materials used in electrochemical double-layer capacitors (EDLCs) is currently limited by several factors, including inaccessible isolated micropores in high-surface area carbons, the finite density of states resulting in a quantum capacitance in series to Helmholtz double-layer capacitance, and the presence of surface impurities, such as functional groups and adsorbed species. To unlock the full potential of EDLC active materials and corresponding electrodes, several post-production treatments are commonly proposed to improve their capacitance and, thus, the energy density of the corresponding devices. In this work, we report a systematic study of the effect of a prototypical treatment, namely H2-assisted thermal treatment, on the chemical, structural, and thermal properties of activated carbon and corresponding electrodes. By combining multiple characterization techniques, we clarify the actual origins of the improvement of the performance (e.g., > +35% energy density for the investigated power densities in the 0.5–45 kW kg–1 range) of the EDLCs based on treated electrodes compared to the case based on the pristine electrodes. Contrary to previous works supporting a questionable graphitization of the activated carbon at temperatures