Ultra‐High Surface Area Nitrogen‐Doped Carbon Aerogels Derived From a Schiff‐Base Porous Organic Polymer Aerogel for CO2 Storage and Supercapacitors

Nitrogen‐doped carbon aerogels (NCAs) have received great attention for a wide range of applications, from thermal electronics to waste water purification, heavy metal or gas adsorption, energy storage, and catalyst supports. Herein NCAs are developed via the synthesis of a Schiff‐base porous organic polymer aerogel followed by pyrolysis. By controlling the pyrolysis temperature, the polymer aerogel can be simply converted into porous NCAs with a low bulk density (5 mg cm−3), high surface area (2356 m2 g−1), and high bulk porosity (70%). The NCAs containing 1.8–5.3 wt% N atoms exhibit remarkable CO2 uptake capacities (6.1 mmol g−1 at 273 K and 1 bar, 33.1 mmol g−1 at 323 K and 30 bar) and high ideal adsorption solution theory selectivity (47.8) at ambient pressure. Supercapacitors fabricated with NCAs display high specific capacitance (300 F g−1 at 0.5 A g−1), fast rate (charge to 221 F g−1 within only 17 s), and high stability (retained >98% capacity after 5000 cycles). Asymmetric supercapacitors assembled with NCAs also show high energy density and power density with maximal values of 30.5 Wh kg−1 and 7088 W kg−1, respectively. The outstanding CO2 uptake and energy storage abilities are attributed to the ultra‐high surface area, N‐doping, conductivity, and rigidity of NCA frameworks.