Self-assembly of one-dimensional nitrogen-doped hollow carbon nanoparticle chains derived from zinc hexacyanoferrate coordination polymer for lithium-ion capacitors

•N doping leads to the formation of 1D hollow carbon nanoparticle chains (CNCs).•N-doped mesoporous CNCs feature bimodal pore size distribution.•Lithium ions are stored in N-doped CNCs through intercalation and adsorption.•Capacitive performance of N-doped CNCs is superior to that of commercial CNTs.

One-dimensional nitrogen-doped hollow carbon nanoparticle chains (CNCs) featuring bimodal pore size distribution were obtained by direct thermal pyrolysis of a three-dimensional cyanide-bridged coordination polymer precursor (zinc hexacyanoferrate) without the need for additional carbon, nitrogen, and catalyst sources. Nitrogen doping turned out to play the key role in the formation of mesoporous compartment layers and structural defects in the CNCs. Small mesopores in the walls provided high surface area for charge storage and allowed the migration of electrolyte into the compartments. Large mesopores in the hollow compartments accommodated electrolyte for easy transport of lithium ions. The commercial multiwalled carbon nanotube (CNT) electrode stored lithium ions primarily through the intercalation process, while the CNC electrode stored lithium ions through both the intercalation and adsorption processes. Thus, the CNC electrode exhibited superior supercapacitive performance than the CNT electrode. The CNC electrode with low internal resistance could deliver a high capacitance of 680 F g−1 at 1 A g−1 in the working potential range of 0.01-3.50 V vs. Li/Li+, which was much better than the commercial CNT electrode (252 F g−1).

Graphical abstractOne-dimensional nitrogen-doped carbon nanoparticle chains facilitate the transport of electrons and lithium ions, showing good supercapacitive performance towards the lithium ions.Download high-res image (184KB)Download full-size image