Carbon Materials as a Conductive Skeleton for Supercapacitor Electrode Applications: A Review

Abstract

Supercapacitors have become a popular form of energy-storage device in the current energy and environmental landscape, and their performance is heavily reliant on the electrode materials used. Carbon-based electrodes are highly desirable due to their low cost and their abundance in various forms, as well as their ability to easily alter conductivity and surface area. Many studies have been conducted to enhance the performance of carbon-based supercapacitors by utilizing various carbon compounds, including pure carbon nanotubes and multistage carbon nanostructures as electrodes. These studies have examined the characteristics and potential applications of numerous pure carbon nanostructures and scrutinized the use of a wide variety of carbon nanomaterials, such as AC, CNTs, GR, CNCs, and others, to improve capacitance. Ultimately, this study provides a roadmap for producing high-quality supercapacitors using carbon-based electrodes.

Keywords: carbon materials; energy storage; nanoarchitectures; supercapacitors.

Figure 1

Diagram illustrating the uses of graphene and graphene derivatives in numerous battery storage and conversion technologies. Reproduced with permission from [46].

Figure 2

One- to two-dimensional nanostructured carbon-based materials. Reproduced with permission from [49].

Figure 3

CQD–Bi2O3 composite used as a supercapacitor electrode. Reproduced with permission from [52].

Figure 4

Denatured milk carbon quantum dots for effective chromium-ion detection and supercapacitor applications [52].

Figure 5

(a) The schematic diagram for composites of PEDOT:PSS with nanostructured carbon materials; Cross-sectional SEM images of (b) PEDOT:PSS, (c) PEDOT:PSS/C₆₀, (d) PEDOT:PSS/SWCNT, and (e) PEDOT:PSS/rGO films. Reproduced with permission from [57].

Figure 6

Illustration of various types of two-dimensional nanomaterials for electrode materials in supercapacitors. Reproduced with permission from [64].

Figure 7

Electrochemical performance of ZCNs electrodes: (a) CV curves of ZCNs-4 at various scanning rates; (b) galvanostatic charge/discharge curves under various current densities for ZCNs-4; (c) specific capacitance dependence on current density of ZCNs-4 and ZCNs-12; (d) long-term cycle stability of ZCNs-4 at a current density of 2 A g⁻¹. Reproduced with permission from [69].

Figure 8

Different kinds of carbon combined with 3D carbon-based nanostructures and pseudo- active materials. Reproduced with permission from [72].

Figure 9

N-rich 3D hierarchical porous carbons shown schematically (a); the creation of porous carbons doped with several heteroatoms (b); packing rigor (c); Ragone plots (d). Reproduced with permission from [78].

Figure 10

Schematic diagram of (a) an electrical double-layer capacitor (EDLC) and (b) a pseudocapacitor (PC). Reproduced with permission from [79].

Figure 11

Progress of carbon-based materials. Reproduced with permission from [80].

Figure 12

A schematic illustration of the experimental techniques used to create 3D mesoporous hybrid CNT/oxide architectures. Reproduced with permission from [86].

Figure 13

A schematic illustration of the experimental techniques used to create 3D mesoporous hybrid CNT/oxide architectures and 3D mesoporous metal oxide structures. Reproduced with permission from [88].

Figure 14

A synthetic approach for TMO@CNT hybrid materials, involving pre-coating CNT with sulfonated polystyrene, depicted schematically. Reproduced with permission from [89].

Figure 15

(A) Schematic illustration of the formation of the MoO₃/PANI coaxial heterostructure nanobelts. (B) SEM images of the original α-MoO₃ nanobelts. (C) SEM images and (inset) TEM images of the as-synthesized MoO₃/PANI coaxial heterostructure nanobelts. (D) A comparison of the galvanostatic charge–discharge curves of the two comparative materials at a current density of 2 A/g. (E) EIS spectra comparison and (F) cycling performance at a scan rate of 50 mV/s of the two comparative materials. (G) Schematic illustration for the synthesis process of 3D MoO₃/PANI hybrid nanosheet network film. (H) CV curves of MoO₃, PANI, and 3D MoO₃/PANI hybrid nanosheet network films in the potential range from −0.6 to 1 V at a scanning rate of 50 mV/s. (I) Nyquist plots of the MoO₃, PANI, and 3D MoO₃/PANI hybrid nanosheet network films. Reproduced with permission from [90].

Figure 16

(a) A schematic depiction of a potential formation pathway for a Ni(OH)2-MnO2-rGO hybrid sphere, with (b) SEM results. Reproduced with permission from [91].

Figure 17

(a) Schematic of the flexible symmetric supercapacitor. (b) CV graphs for symmetric CNT/metal-sulfide supercapacitor devices at 100 mV s⁻¹ in polysulfide electrolyte. (c) Charge-discharge curve at 1 mA cm⁻², (d) specific capacitance versus current density, (e) stability performance and (f) Ragone plot for symmetric CNT/metal-sulfide supercapacitor cells. Reproduced with permission from [94].

Figure 18

Carbon dot/copper sulfide nanoparticles-adorned GO hydrogel for storage applications. Reproduced with permission from [97].

Figure 19

Efficient Electrodes for high-performance supercapacitors using transition-metal sulfide nanostructures. Reproduced with permission from [98].

Figure 20

High-energy supercapacitor applications that are driving the development of carbon-based copper sulfide nanocomposites. Reproduced with permission from [94].

Figure 21

Challenges and opportunities for metal sulfide materials in supercapacitors. Reproduced with permission from [95].

Figure 22

Stretchable supercapacitors utilizing conductive polymers. Reproduced with permission from [102].

Figure 23

GCD curves of (A) PPy, (B) PPy@Cdots(1:1), (C) PANI, and (D) PANI@Cdots(1:0.4) at different current densities specific capacitance of (E) PPy and PPy@Cdots(1:1), and (F) PANI and PANI@Cdots(1:0.4). Coulombic efficiency of (G) PPy and PPy@Cdots(1:1) and (H) PANI and PANI@Cdots(1:0.4). Reproduced with permission from [103].

Figure 24

Investigation of the electrochemical properties of PPy, CDs/PPy, GO/PPy, and GO/CDs/PPy composites: (a) GCD curves at 0.5 A g⁻¹ current density; (b) GO/CDs/PPy GCD curves at various current densities; (c) CV curves at 10 mV s⁻¹ scan rate; (d) GO/CDs/PPy CV curves. Reproduced with permission from [104]; (e) Cycling stability; (f) Nyquist plots.

Figure 25

(a) CV curves of pure PPY, SnO2QDs, GO, and SnO2QDs/GO/PPY nanocomposites; (b) CV plot of SnO2QDs/GO/PPY nanocomposites; (c) cyclic voltammetry variation of Csp of various materials; (d) GCD of different nanocomposites; (e) GCD plots for SnO2QDs/GO/PPY ternary materials at different CD; (f) Csp of nanocomposites from GCD curve. Reproduced with permission from [105].

Figure 26

A schematic approach for synthesizing multi-heteroatom co-doped porous carbon for energy storage. Reproduced with permission from [107].

Figure 27

(a) CV curves at different scan rates and (b) GCD curves at different current densities of Zn-HPC@CF. (c) The CV curves at 2.5 mV s⁻¹. (d) The GCD curves at 1 A g⁻¹. Reproduced with permission from [108].

Figure 28

Superior performance in supercapacitors using multi-heteroatom-doped hierarchical porous carbon produced from chestnut shells. Reproduced with permission from [109].

Figure 29

EC study of the CSC-800/CSC-800: (a) CV curves with different voltages; (b) CV curve with a range of scan rates from 10 to 1000 mV s⁻¹; (c) GCD curves with a different CD; (d) Csp vs. CD; and (e,f) Ragone plots. Reproduced with permission from [110].

Figure 30

CV results of (a) PH-900 (b) PHC-900, GCD results of (c) PH-900 (d) PHC-900 (e) scan rate dependent specific capacitance and (f) current density dependant specific capacitance (g) comparison of GCD curves at 0.1 A/g current density (h) EIS spectra (inset at high resolution at the higher frequency range). Reproduced with permission from [114].

Figure 31

NiS/carbon hexahedrons produced from a nitrilotriacetic acid assembly for supercapacitors. Reproduced with permission from [117].

Figure 32

Controlled porous carbon synthesis and electrochemical performance of supercapacitors. Reproduced with permission from [118].

Figure 33

Microwave treatment of chili-straw pyrolysis residue yields high-value porous carbon. Reproduced with permission from [119].

Figure 34

Porous carbon material originated from wild rice stem and used in supercapacitors. Reproduced with permission from [120].