Self-Template Synthesis of Nitrogen-Doped Hollow Carbon Nanospheres with Rational Mesoporosity for Efficient Supercapacitors

Abstract

Rational design and economic fabrication are essential to develop carbonic electrode materials with optimized porosity for high-performance supercapacitors. Herein, nitrogen-doped hollow carbon nanospheres (NHCSs) derived from resorcinol and formaldehyde resin are successfully prepared via a self-template strategy. The porosity and heteroatoms in the carbon shell can be adjusted by purposefully introducing various dosages of ammonium ferric citrate (AFC). Under the optimum AFC dosage (30 mg), the as-prepared NHCS-30 possesses hierarchical architecture, high specific surface area up to 1987 m2·g−1, an ultrahigh mesopore proportion of 98%, and moderate contents of heteroatoms, and these features endow it with a high specific capacitance of 206.5 F·g−1 at 0.2 A·g−1, with a good rate capability of 125 F·g−1 at 20 A·g−1 as well as outstanding electrochemical stability after 5000 cycles in a 6 M KOH electrolyte. Furthermore, the assembled NHCS-30 based symmetric supercapacitor delivers an energy density of 14.1 W·h·kg−1 at a power density of 200 W·kg−1 in a 6 M KOH electrolyte. This work provides not only an appealing model to study the effect of structural and component change on capacitance, but also general guidance to expand functionality electrode materials by the self-template method.

Blowing Agent-Induced Hierarchical Porous Carbon from Low-Quality Coal for High-Performance Supercapacitor

“…Figure d and e demonstrates the CV at different scan rates and GCPL at different current densities of the HCK3 sample, respectively. A quasi-rectangular shape without any redox peak even at higher scan rates contributes to the excellent rate capability due to low inner resistance and fast ion kinetics . The presence of mesopores coupled with high electrical conductivity provides the excellent prospect of synthesized porous carbon materials as efficient electrode materials for supercapacitors and other electrochemical applications.…”

“…A quasi-rectangular shape without any redox peak even at higher scan rates contributes to the excellent rate capability due to low inner resistance and fast ion kinetics. 53 The presence of mesopores coupled with high electrical conductivity provides the excellent prospect of synthesized porous carbon materials as efficient electrode materials for supercapacitors and other electrochemical applications. The GCPL curves of HCK3 at the current densities of 0.5, 1, 2, 3, 5, and 10 A/g are described in Figure 7e.…”

Carbon Nanomaterials‐Enabled High‐Performance Supercapacitors: A Review

“…Carbon nanospheres, carbon nanocages, and CNFs are also suitable for SC electrodes. Zhao et al [ 199 ] prepared N‐doped hollow carbon nanospheres (NHCSs) using resorcinol and formaldehyde as precursors shown in Figure , which featured the SSA and mesopore proportion of 1987 m 2 g −1 % and 98%, respectively, and yielded a specific capacitance of 206.5 F g −1 at the current density of 0.2 A g −1 . The symmetric SC cell fabricated by NHCSs exhibited an energy density and power density of 14.1 Wh kg −1 and 200 W kg −1 , respectively.…”

“…Reproduced under the terms of the CC‐BY license. [ 199 ] Copyright 2021, The Authors. Published by MDPI.…”

“…The record energy density for symmetrical pure carbonbased SCs is over 50 Wh kg À1 , [144] while for hybrid devices it exceeds 300 Wh kg À1 . [111] Together with the merits of high power [199] Copyright 2021, The Authors. Published by MDPI.…”