Nature‐inspired porous multichannel carbon monolith: Molecular cooperative enables sustainable production and high‐performance capacitive energy storage

Abstract

Abstract The advancement of supercapacitors (SCs) is closely bound up with the breakthrough of rational design of energy materials. Freestanding and thick carbon (FTC) materials with well‐organized porous structure is promising SC electrode delivering high areal capacitive performance. However, controllable and sustainable fabrication of such FTC electrode is still of great challenges. Inspired by natural honeycombs with cross‐linked multichannel structure, herein, an innovative molecular‐cooperative‐interaction strategy is elaborately provided to realize honeycomb‐like FTC electrodes. The nitrogen‐doped porous carbon monolith (N‐PCM) is obtained with advantages of interconnect pore structure and abundant nitrogen doping. Such strategy is based on naturally abundant molecular precursors, and free of pore‐templates, expensive polymerization catalyst, and dangerous reaction solvent, rendering it a sustainable and cost‐effective process. Systematic control experiments reveal that strong interactions among molecular precursors promise the structural stability of N‐PCM during carbonization, and rational selection of molecular precursors with chemical blowing features is key step for well‐developed honeycomb‐like pore structure. Interestingly, the optimized sample exhibits hierarchical pore structure with specific surface area of 626.4 m2 g−1 and rational N‐doping of 7.01 wt%. The derived SC electrode with high mass loading of 40.1 mg cm−2 shows an excellent areal capacitance of 3621 mF cm−2 at 1 mA cm−2 and good rate performance with 2920 mF cm−2 at 25 mA cm−2. Moreover, the constructed aqueous symmetric SC and quasi‐solid‐state SC produce high energy densities of 0.32 and 0.27 mWh cm−2, respectively. We believe that such a composition/microstructure controllable method can promote the fabrication and development of other thick electrodes for energy storage devices.

Keywords

• carbon monolith
• freestanding
• high mass loading
• molecular cooperative
• supercapacitors
• thick electrode