Large-Pore Ordered Mesoporous Turbostratic Carbon Films Prepared Using Rapid Thermal Annealing for High-Performance Micro-pseudocapacitors

• Published in: ACS applied materials & interfaces 2021-12, Vol.13 (51), p.61027-61038
• Main Authors: Bhardwaj, Ayush, Pagaduan, James Nicolas, Yu, Yong-Guen, Einck, Vincent J, Nuguri, Sravya, Katsumata, Reika, Watkins, James J
• Format: Article
• Language: English
• Subjects: Energy, Environmental, and Catalysis Applications
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.1c16666

Carbonization by rapid thermal annealing (RTA) of precursor films structured by a brush block copolymer-mediated self-assembly enabled the preparation of large-pore (40 nm) ordered mesoporous carbon (MPC)-based micro-supercapacitors within minutes. The large pore size of the fabricated films facilitates both rapid electrolyte diffusion for carbon-based electric double-layer capacitors and conformal deposition of V2O5 without pore blockage for pseudocapacitors. The pores were templated using bottlebrush block copolymers (BBCPs) via cooperative assembly of phenol-formaldehyde resin to produce microphase-segregated carbon precursor films on a variety of substrates. Ultrafast RTA processing (∼50 °C/s) at elevated temperatures (up to 1000 °C) then generated stable, conductive, turbostratic MPC films, resolving a significant bottleneck in rapid fabrication. MPC prepared on stainless steel at 900 °C demonstrated exceptionally high areal and volumetric capacitances of 6.3 mF/cm2 and 126 F/cm3 (at 0.8 mA/cm2 using 6 M KOH as the electrolyte), respectively, and 91% capacitance retention after 10,000 galvanostatic charge/discharge cycles. Post-RTA conformal V2O5 deposition yielded pseudocapacitors with 10-fold increase in energy density (20 μW h cm–2 μm–1) without adversely affecting the high power density (450 μW cm–2 μm–1). The use of RTA coupled with BBCP templating opens avenues for scalable, rapid fabrication of high-performance carbon-based micro-pseudocapacitors.