Ultra-thin highly-wrinkled graphene-like nanosheets for supercapacitor electrodes via 4-nitrocatechol and solvent-induced self-assembly

Graphene-like carbon materials are in high demand due to their potential applications in power devices. However, conventional synthesis of graphene-like materials causes repacking to occur during high-pressure compression steps resulting in low surface areas and unfavorable structures for mass transfer. Herein, ultra-thin wrinkled graphene-like nanosheets (GNs) were prepared simply via classical evaporation induced self-assembly (EISA) of 4-nitrocatechol as carbon precursor. Combination of EISA and subsequent KHCO3 activation and calcination at 900 °C (GN-900) afforded materials with thicknesses of (2–3) nm, specific surface areas of 3300 m2 g−1 with specific pore volumes of 2.34 cm3 g−1 under optimum conditions. When GN-900 was evaluated as an electrode material, a specific capacitance of 367 F g−1 was achieved at 0.2 A g−1 current density in 6 M KOH aqueous solution with a rate capability of 228 F g−1 at 40 A g−1. Supercapacitors assembled with GN-900 had specific energy densities of 11.5 Wh kg−1 at power densities of 89.8 W kg−1. Moreover, capacitance retention was greater than 98% after 3000 cycles at 10A g−1. Materials prepared with the proposed methods in this study were determined to be structurally stable and to exhibit favorable electrochemical performance for present and near-future supercapacitor applications.