Amine-aldehyde resin derived porous N-doped hollow carbon nanorods for high-energy capacitive energy storage

Abstract

Electrochemical double layer capacitors (EDLCs) are known for their high power density but hampered by low energy density. Herein, N-doped hollow carbon nanorods (NHCRs) have been constructed by a hard templating method using MnO2 nanorods as the hard templates and m-phenylenediamine-formaldehyde resin as the carbon precursor. The NHCRs after activation (NHCRs-A) manifest abundant micropores/mesopores and an ultrahigh surface area (2166 m2 g−1). When employed in ionic liquid (IL) electrolyte-based EDLCs, the NHCRs-A delivers a high specific capacitance (220 F g−1 at 1 A g−1), an impressive energy density (110 Wh kg−1), and decent cyclability (97% retention over 15 000 cycles). The impressive energy density is derived from the abundant ion-available micropores, while the decent power density is originated from the hollow ion-diffusion channels as well as excellent wettability in ILs. In situ infrared spectroscopy together with in situ Raman unveil that both counter-ion adsorption and ion exchange are involved in the charge storage of NHCRs-A. This study provides insight into the construction of porous carbon materials for EDLCs.