Synthesis and enhanced supercapacitor performance of carbon self‐doping graphitic carbon nitride/NiS electrode material

Abstract

The thermal oxidation carbon self-doped graphitic carbon nitride/NiS (TC-g-C 3 N 4 / NiS) composites with high electrochemical performance were synthesized by combining nickel sulfide with carbon self-doping carbon nitride through a hydrothermal method. The graphitic carbon nitride (g-C 3 N 4) could improve charge fluidity by carbon self-doping process, and be etched by further heat treatment, which provides conditions for the introduction of NiS particles. NiS particles uniformly adhered to the layers of g-C 3 N 4 , thus avoiding particle aggregation. The as-prepared active composite maintains high specific capacitance (1162 F/g at the current density of 1 A•g −1) and shows great cycle stability (capacitance retention rate of 82.0% after 8000 cycles). The conductivity of active composite has also been improved. Moreover, the assembled TC-g-C 3 N 4 /NiS//AC exhibit a relatively high-energy density of 27 Wh/kg and exhibits excellent cycling performance with a capacity retention rate of 87.9% after 8000 cycles. Hence one can see that TC-g-C 3 N 4 /NiS composites have broad application prospects in the field of supercapacitors.

Highly Stable Supercapacitor Devices Based on Three-Dimensional Bioderived Carbon Encapsulated g-C3N4 Nanosheets

“…First, the HR-XPS spectrum of C 1s of the pristine GCN sample, Figure 4a, shows two main peaks at 284.6 eV (ascribed to C−C bond) and a peak at 288.0 eV (attributed to C−NC). 30,44 The C 1s spectrum of the GCN/Bio-C20 composite, Figure 4b, is deconvoluted into three peaks. Besides the two peaks corresponded to C−C bond and C−NC bonds, the sp 2 hybridized carbon−nitrogen double bond appears at 287.7 eV, revealing the successful combination of biocarbon in the graphitic structure.…”

2D Graphitic Carbon Nitride for Energy Conversion and Storage

“…Sun et al. [ 251 ] combined nickel sulfides (NiS) with carbon self‐doping g‐C 3 N 4 to obtain the C self‐doped graphitic g‐C 3 N 4 /NiS (TC‐g‐C 3 N 4 /NiS) composite material ( Figure a). C self‐doped g‐C 3 N 4 was prepared by solvothermal method and multistep thermal oxidation, and the substitution of C for bridge N atoms can cause delocalized π bonds, which are beneficial to the charge transfer (Figure 28b).…”

“…Transition metal hydroxides are representative active electrochemical pseudocapacitive electrode materials, which are well known for their high theoretical capacitance and high energy density. Aghazadeh et al [254] obtained g-C 3 N 4 nanosheets using ultrasonication-assisted liquid phase exfoliation method and electrochemically co-embedded them with Co(OH) 2 in a Ni-foam support using a simple electrodeposition procedure [251] Copyright 2020, Wiley-VCH. e) TEM image of Co 3 S 4 /g-C 3 N 4 -10. f) CV curves of Co 3 S 4 , g-C 3 N 4 and Co 3 S 4 /g-C 3 N 4 composites at a scan rate of 50 mV s −1 .…”

“…Adapted with permission. [ 251 ] Copyright 2020, Wiley‐VCH. e) TEM image of Co 3 S 4 /g‐C 3 N 4 ‐10.…”

“…d) Specific capacitance of TC-g-C 3 N 4 , NiS, BC-g-C 3 N 4 /NiS, and TC-g-C 3 N 4 /NiS at different current density. Adapted with permission [251]. Copyright 2020, Wiley-VCH.…”