One-Step Synthesis of Hierarchical, Bimodal Nanoporous Carbons via Co-templating with Bottlebrush and Linear Block Copolymers

Abstract

We report the preparation of hierarchically ordered porous carbon films with ∼5 nm mesopores distributed within a continuous carbon framework surrounding ∼100 nm macropores. The hierarchical carbons are prepared using bottlebrush block copolymers (BBCP) of large molecular weight (Mw = 1800 kg mol–1), low-molecular-weight linear block copolymers (LBCPs), and phenol-formaldehyde resin, which cooperatively assemble to yield “planet–satellite” morphologies following carbonization. The combination of BBCPs and LBCPs as co-templates enables a generalized strategy to design functional materials in which the pore sizes of both the mesopores and macropores are tuned within a continuous matrix and the mesopores uniformly surround macropores. The template is an ideal route for fabrication of tailored devices. The hierarchical carbon films exhibit exceptional performance as supercapacitor electrodes, with capacitance reaching up to C = 1420 mF cm–2 at 16 mA cm–2 (corresponding to 177 F g–1 at 2 A g–1 with mass loading 8 mg cm–2) resulting from a combination of high surface area and controlled pore structures. In such an application, the hierarchical carbons outperform devices that contain exclusively mesopores templated by the LBCP or only the macropores templated by the BBCP.