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

Abstract

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.

Direct synthesis of ordered mesoporous materials from thermoplastic elastomers

“…3-10 nm) due the low molecular weight (MW) nature of templates. Increasing the window of accessible pore sizes can be achieved through using high-molecular weight block copolymers (BCP) as templates or introduction of pore expanders, which may require multistep custom synthesis that can be challenging/high-cost at commercial scales [18][19][20] . As an alternative to templating methods, direct conversion of self-assembled BCPs to OMCs can be achieved through steps of crosslinking and carbonization.…”

Al Foil-Supported Carbon Nanosheets as Self-Supporting Electrodes for High Areal Capacitance Supercapacitors

“…The areal capacitance obtained from GCD is higher than that obtained from CV, attributed to a longer charge/discharge time for GCD, which ensures more time for generating pseudocapacitance. The maximum areal capacitance of CNS-120 is superior to some previously reported electrode materials, such as MPC (6.3 mF cm −2 at 0.8 mA cm −2 ) [ 61 ], HCSs (6.1 mF cm −2 at 0.5 mA cm −2 ) [ 62 ], 3D FC-CNT@P (5.53 mF cm −2 at 0.1 mA cm −2 ), and N-doped sucrose carbon (3.9 mF cm −2 at 5 mV s −1 ) [ 63 ], as well as laser-induced graphene (4 mF cm −2 at 0.01 mA cm −2 ) [ 58 ]. More details of the comparisons between CNS-120 and the previously reported material electrodes are summarized in Table S2 [ 64 , 65 ].…”

Mesoporous carbons from self‐assembled polymers

“…The ability of producing such large pores using BCPs as templates was very rarely demonstrated before, and therefore this work not only extended the use of bottlebrush BCPs for synthesizing MCs, but also showed an effective approach to produce large‐pore nanoporous carbons. To highlight the advantage of forming large pores in MCs using bottlebrush BCP templates, these nanoporous carbon films were back‐filled with vanadium oxide (e.g., V 2 O 5 ) through conformal deposition (without pore blockage) for demonstrating their use in high‐performance micro‐pseudocapacitors 142 …”

“…To highlight the advantage of forming large pores in MCs using bottlebrush BCP templates, these nanoporous carbon films were back-filled with vanadium oxide (e.g., V 2 O 5 ) through conformal deposition (without pore blockage) for demonstrating their use in high-performance micro-pseudocapacitors. 142 Additionally, bottlebrush BCPs can be combined with other linear BCPs to serve as co-templates, yielding hierarchical porous materials with multimodal morphologies. As shown in Figure 5C,D, Fei et al 141 designed planetsatellite structures of hierarchically ordered bimodal porous carbon films with tunable mesopores by simultaneously employing two different BCP templates, which contains both mesopores (from PS-b-PEO, or F127) and macropores (from PDMS-b-PEO bottlebrush BCPs), for preparing high-performance supercapacitor electrodes.…”