O/N Co‐Doped, Layered Porous Carbon with Mesoporosity up to 99 % for Ultrahigh‐Rate Capability Supercapacitors

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‐co‐doped mesoporous carbons with ultrahigh mesoporosity and well‐defined mesopores by one‐step Na2CO3‐activation of covalent triazine‐based frameworks that derive from 2,4,6‐tris(4‐cyanophenoxy)‐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 m2 g−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−1 at 1.0 A g−1 and an ultrahigh rate capability of 66.1 % at 1–1000 A g−1 in alkaline electrolyte. Moreover, the CTFC‐900‐based supercapacitor in neutral electrolyte achieved both high energy density (32.2 Wh kg−1) and high power density (187 kW kg−1).