Ultrahigh-rate capability supercapacitors that can tolerate charging/discharging at ultrahigh current density are particularly attractive for high-power applications. At present, mesopore-engineering and heteroatom-doping have been proven to be the effective ways for concurrently enhancing energy density and rate capability. Herein, we report the fabrication of O/N-codoped mesoporous carbons with ultrahigh mesoporosity and well-defined mesopores by one-step Na 2 CO 3-activation of covalent triazine-based frameworks that derive from 2,4,6-tris(4cyanophenoxy)-1,3,5-triazine monomer (CTFO) at 800-1000°C. The as-obtained O/N-co-doped carbon (CTFC-900) with up to 99 % mesoporosity possesses a layered structure together with a high specific surface area (2425 m 2 g À 1) and a high N/O content (6.98 at% N and 10.32 at% O). Owing to these merits, the supercapacitor based on CTFC-900 electrode exhibited a high specific capacitance of 287 F g À 1 at 1.0 A g À 1 and an ultrahigh rate capability of 66.1 % at 1-1000 A g À 1 in alkaline electrolyte. Moreover, the CTFC-900-based supercapacitor in neutral electrolyte achieved both high energy density (32.2 Wh kg À 1) and high power density (187 kW kg À 1).

The exploration of highly efficient, low-cost, and durable oxygen reduction reaction (ORR)/oxygen evolution reaction (OER) bifunctional electrocatalysts is extremely desirable but challenging for the practical application of Zn–air batteries. Herein, we report the fabrication of a FeNi alloy nanoparticle (NP)-decorated N,S dual-doped carbon nanocomposite (denoted FeNi/NS-C) as a bifunctional electrocatalyst for Zn–air batteries. The FeNi/NS-C electrocatalyst is produced through the complexation of a N-rich imidazolyl-phenanthroline derivative with metal salts, followed by pyrolysis in the presence of trithiocyanuric acid (TTCA). The FeNi/NS-C electrocatalyst shows comparable ORR activity to that of Pt/C (E 1/2 = 0.83 V) and superior OER activity to that of IrO2 (E j=10 = 1.585 V). The liquid- and solid-state Zn–air batteries assembled with the FeNi/NS-C exhibit high power density and specific capacity. In particular, the FeNi/NS-C-based Zn–air batteries display remarkable durability over 1000 h at 5 mA cm–2 and 70 h at 2 mA cm–2 in liquid and solid electrolytes, respectively. The high performance of the FeNi/NS-C may be related to the synergistic effect of the bimetallic alloy NPs and the N,S dual-doped carbon matrix with a high surface area, porous structure, and unique hybridized morphology.

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