One-pot synthesis of unique skin-tissue-bone structured porous carbons for enhanced supercapacitor performance

Introduction of hierarchical porous structure and heteroatom in porous carbons are always effective approaches to improve the capacitive performance for supercapacitor. However, it is still a challenge to achieve the desired structure characteristics by a convenient one-step synthesis. Herein, C₁₆mimPF₆, an ionic liquid, was introduced in the self-assembly process of poly-benzoxazine to obtain a unique skin-tissue-bone structured hierarchical porous carbon with homogeneous N, P co-doping after carbonization. As the key component, C₁₆mimPF₆ works not only as a structure-directing agent to form a hierarchical structure through microphase separation mechanism, thereby promoting the transfer of ion and electron, but also as a heteroatom precursor to contribute an additional pseudocapacitance by doping phosphorus atoms on carbon matrix. The obtained porous carbon displays a high gravimetric capacitance (C_g) of 209 F g^-1 (especially in the carbons prepared without corrosive activation step), a good volumetric capacitance (C_v) of 132 F cm^-3 and an excellent area-normalized capacitance (C_a) of 35 μF cm^-2. Overall, this work opens a new way to design the polymer-derived carbons with easy heteroatoms doping and hierarchical porous structure.