Engineered Fabrication of Hierarchical Frameworks with Tuned Pore Structure and N,O-Co-Doping for High-Performance Supercapacitors

Abstract

A series of multiheteroatom porous carbon frameworks (MPCFs) is prepared successfully from the trimerization of cyano groups of our designed and synthesized 4,4'-(4-oxophthalazine-1,3(4H)-diyl)dibenzonitrile monomers and subsequent ionothermal synthesis. Benefiting from the molecular engineering strategy, the obtained MPCFs framework show a homogeneous distribution of nitrogen and oxygen heteroatoms at the atomic level, confirmed by the transmission electron microscopy mapping intuitively, thereby ensuring the stability of electrical properties. The supercapacitor with the obtained MPCFs@700 as the electrode exhibits a high energy density of 65 Wh kg at 0.1 A g, with excellent long cycle life and cycle stability (98% capacitance retention for 10 000 cycles in 1-butyl-3-methylimidazolium tetrafluoroborate). Another two electrolyte systems employed also demonstrate the delightful results, showing a 112% capacitance retention for 30 000 cycles in 1 M HSO and a 95% capacitance retention for 30 000 cycles in tetraethylammonium tetrafluoroborate in an acetonitrile solution. Moreover, the successful preparation of MPCFs provides new insights into the fabrication of electrode materials intrinsically containing nitrogen and oxygen in the frameworks for readily available components through a facile routine.

A Hollow Microtubular Triazine‐ and Benzobisoxazole‐Based Covalent Organic Framework Presenting Sponge‐Like Shells That Functions as a High‐Performance Supercapacitor

“…The CV curves all had rectangular shapes, even when recorded at the highest scan rate of 200 mV s −1 , suggesting capacitive behavior with a high rate performance suitable for use in supercapacitors . The distinct appearance of humps in the rectangular CV curves revealed that the capacitive response was derived from a combination of electric double‐layer capacitance (EDLC) and pseudocapacitance arising from the presence of heteroatoms (i.e., nitrogen and oxygen atoms) . Figure b provides galvanostatic charge‐discharge (GCD) curves of the TPT‐DAHQ COF recorded at various current densities, from 0.5 to 20 A g −1 .…”

“…Figure b provides galvanostatic charge‐discharge (GCD) curves of the TPT‐DAHQ COF recorded at various current densities, from 0.5 to 20 A g −1 . The GCD curves display triangular shapes with a slight bend, implying the existence of both EDLC and pseudocapacitance arising from heteroatoms (i.e., nitrogen and oxygen atoms) . The specific capacitance was calculated from the GCD curves using equation (S1) as shown in Figure c. The TPT‐DAHQ COF exhibited excellent specific capacitance of 256 F g −1 at current density of 0.5 A g −1 which was decreased to 131 F g −1 when the current density was increased to 20 A g −1 .…”

“…The specific capacitance was calculated from the GCD curves using equation (S1) as shown in Figure c. The TPT‐DAHQ COF exhibited excellent specific capacitance of 256 F g −1 at current density of 0.5 A g −1 which was decreased to 131 F g −1 when the current density was increased to 20 A g −1 . This excellent performance could be attributed to the higher surface area (1855 m 2 g −1 ) and the existence of mesoporosity (pore size of 2.3 nm) along with the presence of heteroatoms (nitrogen and oxygen), which enable easier accessibility of electrolytes to the electrode surface ,. The reported specific surface area and specific capacitance values are summarized in Table S4.…”

Density Functional Theory Calculations of the Quantum Capacitance of Graphene Oxide as a Supercapacitor Electrode

“…Graphene, a two‐dimensional single‐atom‐layer carbon material with a high specific surface area as high as 2630 m 2 /g and good electrical conductivity induced by covalently bonded sp 2 carbon atoms, is regarded as one of the most attractive candidate electrode materials of supercapacitors. However, compared with other energy storage devices, graphene supercapacitors exhibit low specific capacitance …”

Covalent Organic Frameworks: A New Class of Porous Organic Frameworks for Supercapacitor Electrodes

“…Some multi‐heteroatom porous carbon frameworks (MPCFs) were prepared successfully by the trimerization of cyano groups of the synthesized 4,4′‐(4‐oxophthalazine‐1,3(4H)‐diyl) dibenzonitrile (OPDN) monomers and subsequent ionothermal synthesis . In the prepared MPCFs framework, nitrogen and oxygen heteroatoms exhibited a homogeneous distribution at the atomic level, hence ensuring the stability of electrical performance for MPCFs.…”