Fullerene-Based In Situ Doping of N and Fe into a 3D Cross-Like Hierarchical Carbon Composite for High-Performance Supercapacitors

Fullerene-based carbons are promising electrode materials for supercapacitors due to their unique carbon structures and tunable architectures at the molecular level. By introducing various functional groups with many elements on the fullerene cages, diverse in situ metal/nonmetal-doped carbon materials with enhanced pseudocapacitances and/or double layer capacitances can be prepared. In the present work, a fullerene derivative, ferrocenylpyrrolidine C-60, containing nitrogen and iron, is chosen as the only precursor. A unique microstructure is fabricated by a liquid-liquid interfacial precipitation process. Subsequently, a facile, one-step annealing of the microstructure at different temperatures is performed. A series of in situ N and Fe-codoped laminated 3D hierarchical carbon composites in the shape of a cross are successfully synthesized. The as-prepared N and Fe-codoped carbon material treated at 700 degrees C exhibits a high specific capacitance of 505.4 F g(-1) at 0.1 A g(-1). To the best knowledge, this is the highest supercapacitor capacitance based on fullerene electrode materials. The use of a fullerene derivative as an in-situ doped carbon for applications in energy storage opens a new avenue for developing future synthetic strategies to extend the repertoire of electrode materials with high performance.