Active Electrode Material For Supercapacitors Research Articles

Synthesis of activated carbon monolith derived from cocoa pods for supercapacitor electrodes application

ABSTRACT Agricultural and agro-industrial residues are ordinary wastes in the forestry industry and their valorization is an important issue.Cocoa (Theobroma cacao) pods waste was chosen as an activated activated carbon material and studied as active materials for supercapacitor electrodes. The carbon electrode has been made using 0.3 M and 0.4 M Potassium Hydroxide (KOH) activators at 700°C. Physical properties were tested by measuring density, X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM), while the electrochemical properties were tested using the Cyclic Voltammetry (CV) method. Activated carbon electrodes were constructed by a combination of chemical activation, and physical activation methods. The technique of making carbon electrodes was started from pre-carbonization, milling, chemical activation, pellet making, carbonization, and physical activation. Analysis of dimensions, density, and specific capacitance in the manufacture of carbon electrodes showed the mass, diameter, thickness, and density of the electrodes decreased with the addition of KOH concentrations from 0.3 M to 0.4 M. While the specific capacitance value of the electrode was directly proportional to the increase of KOH concentration. In XRD measurement data, the values of 2θ in the range of 23.569°–24.747° was obtained for the reflection field 002, and 44.634°–44.781° for the reflection plane 100. X-ray diffraction curve data showed a 0.4 M at 700°C sample having an Lc value and a lattice distance smaller than the sample of 0.3 M at 700°C. Therefore, it could be indicated that the surface area of the sample of 0.4 M at 700°C was greater than the sample of 0.3 M at 700°C. The electrochemical test showed that the method of chemical activation variation of 0.4 M produced electrodes with better performance than 0.3 M. The specific capacitance value obtained at a concentration of 0.3 M was 90.2 F/gr with a density of 0.850 gr/cm3, while at a concentration of 0.4 M was 140.2 F/gr with a density of 0.802 gr/cm3. These results indicate the high potential of agricultural cocoa pods based activated carbon monoliths as supercapacitor electrode.

Advances on Emerging Materials for Flexible Supercapacitors: Current Trends and Beyond

AbstractThe progressive size reduction of electronic components is experiencing bottlenecks in shrinking charge storage devices like batteries and supercapacitors, limiting their development into wearable and flexible zero‐pollution technologies. The inherent long cycle life, rapid charge–discharge patterns, and power density of supercapacitors rank them superior over other energy storage devices. In the modern market of zero‐pollution energy devices, currently the lightweight formula and shape adaptability are trending to meet the current requirement of wearables. Carbon nanomaterials have the potential to meet this demand, as they are the core of active electrode materials for supercapacitors and texturally tailored to demonstrate flexible and stretchable properties. With this perspective, the latest progress in novel materials from conventional carbons to recently developed and emerging nanomaterials toward lightweight stretchable active compounds for flexi‐wearable supercapacitors is presented. In addition, the limitations and challenges in realizing wearable energy storage systems and integrating the future of nanomaterials for efficient wearable technology are provided. Moreover, future perspectives on economically viable materials for wearables are also discussed, which could motivate researchers to pursue fabrication of cheap and efficient flexible nanomaterials for energy storage and pave the way for enabling a wide‐range of material‐based applications.

Designing quinone-dopamine-based conjugates as six electron system for high-performance hybrid electrode

The development of electrode materials for supercapacitors is a necessary research and development work to address the present-day energy crises. The improvement of productive pseudo-capacitors requires quick and reversible kinetics of redox-molecules. In the development of pseudo-capacitors, quinone/hydroquinone redox couples are one of the promising molecules. Graphite sheet, along with quinone molecules with an increased number of carbonyl groups, is expected to give higher performance hybrid supercapacitors. In this direction, a simple one-step reaction of p-benzoquinone and dopamine hydrochloride to 2,5-bis((3,4-dihydroxyphenethyl)amino)cyclohexa-2,5-diene-1,4-dione molecule (BQ-DP) is carried and confirmed the formation from Fourier-transform infrared, high-resolution mass, proton and carbon nuclear magnetic resonance spectra. This molecule is used as a redox system along with a graphite sheet as active electrode material for supercapacitor, wherein a redox system consists of three quinone groups with six electrons transfer reaction. Cyclic voltammetry and charge-discharge graphs, and two constant phase elements obtained from EIS measurement clearly show the contribution of both electrochemical double layer and pseudo-capacitor components. Both benzoquinone and dopamine groups are involved in the redox reaction. The values of specific capacitance for this electrode are 910 F g−1 at 5 mV s−1 and 1180 F g−1 at 9.5 A g−1, respectively. This cell is subjected to 10,000 charge-discharge cycles, which underwent decay in specific capacitance from 416 to 209 F g−1 up to 1000 cycles and then remains constant up to 7000 cycles. In the case of a negligible contribution of EDLC, the supercapacitor cell could be treated as a battery cell. The battery gives an initial specific capacity of 115–58 mAh g−1 at 1000 cycles. This quinone molecule showed higher electrochemical performance compared to the earlier reports on quinone molecules for supercapacitors. An alternative strategy to increase the performance of the quinone-graphite electrode is made by making holes on graphite sheet and accommodated more amount of electro-active quinone molecule and used as an electrode in symmetric cell configuration in coin cell and subjected for 5000 cycles in the voltage range from 0 to 1 V at 9.5 F g−1. The value of specific capacitance for the symmetric cell obtained from charge-discharge measurement for the electrode (419 F g−1) is found to be higher than that of the electrode without holes (324 F g−1).

Ag nanoparticles-decorated CoAl-layered double hydroxide flower-like hollow microspheres for enhanced energy storage performance

Layered double hydroxides (LDHs) have been considered as one class of promising active electrode materials for supercapacitors due to their tunable composition and chemical versatility. Nonetheless, the poor electrical conductivity hinders their further practical applications in supercapacitors. Herein, CoAl LDH flower-like hollow microspheres are decorated with Ag nanoparticles by a facile one-step solvothermal reaction, followed by chemical bath deposition reaction. Experimental results and theoretical calculations indicate that decorating Ag nanoparticles onto CoAl LDH not only reduces the energy band gap and enhances their electrical conductivity, but also promotes fast diffusion kinetics of electrolyte ions and electrochemical reaction activity. Consequently, the prepared Ag/CoAl LDH electrode demonstrates improved specific capacities of 1214 (825) C g−1 at 3 (30) A g−1 and 91% capacity retention over 10,000 cycles at 10 A g−1 compared to the pristine CoAl LDH electrode. Moreover, using Ag/CoAl LDH and N-doped carbon nanotubes as the positive and negative electrodes, respectively, the assembled hybrid capacitor device delivers an energy density of 61.2 Wh kg−1 at a power density of 800 W kg−1. This work may showcase a great promise of engineering conductive nanoparticles-decorated LDHs-based active materials towards high-performance supercapacitors.

Porous trimetallic fluoride Ni–Co–M (M = Mn, Fe, Cu, Zn) nanoprisms as electrodes for asymmetric supercapacitors

Electroactive materials, with high electrochemical activity, are urgently needed for supercapacitors. While it remains a great challenge to integrate high rate capability and outstanding cycling stability simultaneously. Mixed transition metal fluorides with porous structures are regarded as helpful active electrode materials for supercapacitors. Herein, three dimensional porous tri metallic (Ni–Co–M, M = Mn, Fe, Cu, Zn) fluorides were synthesized by reflux condensation and calcination methods. Among them, Ni–Co–Zn fluorides (NCZF) exhibited stronger synergetic electrochemical property compared with other transition metals, contributing a high specific capacitance of 914.4 F/g at 1 A/g and 81.3% capacity retention at 20 A/g and the specific capacitance could maintain 45.6% after 30,000 cycles. The hybrid supercapacitor based on NCZF and activated carbon (AC) electrodes also displayed a specific capacity of 222 F/g at 1 A/g and 90.2 F/g at 20 A/g with ultralong cycling stability (61.9% capacity retention after 10,000 cycles).

Chromium, fluorine and nitrogen tri-doped graphene sheets as an active electrode material for symmetric supercapacitors

The tri-doped (chromium, fluorine and nitrogen) graphene sheets (CFNG) have been prepared using quinolinium fluorochromate (QFC) as the single and novel source. Graphene oxide (GO) and CFNG were synthesized by modified Hummers method and simple hydrothermal method, respectively, and their electrochemical properties towards supercapacitor were studied. The HR-TEM images provide the crumpled sheet like morphology of CFNG. XPS reveals the presence of Cr, F and N in CFNG. The electrochemical studies such as cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge (GCD) were carried out using 1 M H2SO4 to evaluate the capacitive behaviour in three-electrode cells. A better storage capacitive behaviour of about 363 F/g at a current density of 0.5 A/g was achieved by CFNG. The capacitive performance of CFNG was also tested in two electrode cells, in which, a symmetric device was fabricated with CFNG, which exhibited specific capacitance of 160 F/g for 0.5 A/g. The symmetric CFNG supercapacitor device further delivers respective energy density and power density of 14.23 Wh/kg and 300 W/Kg with excellent capacitance retention of 98.8% and coulombic efficiency of 98.3% for over 1000 charge-discharge cycles. The electrochemical results were indicating that CFNG would be a potential candidate as an active electrode material for supercapacitors.

Hollow porous gold nanoparticle/reduced graphene oxide composite films for electrochemical supercapacitor applications

Here, we report the synthesis of hollow porous gold nanoparticles-decorated reduced graphene oxide (HPAuNPs/RGO) nanocomposites and their electrochemical performances as active electrode material for supercapacitors. Accordingly, the HPAuNPs were first prepared using a simple solution phase template method according to the modified literature procedure, and the size control of hollow porous gold particles was achieved by varying the concentration of hydroquinone used as the reducing agent. Then, the surface of the RGO nanosheets was decorated with HPAuNPs through the self-assembly approach. The structural and morphological features of synthesized nanoparticles and nanocomposites were evaluated by spectroscopic and morphologic methods. Also, the electrochemical supercapacitive performances of the HPAuNPs/RGO/GC nanocomposite electrodes as both cathode and anode materials were analyzed in Na2SO4 solution using electrochemical methods. As a control sample, the RGO/GC electrode was also examined under identical experimental conditions. The results indicate that the composite materials display higher specific capacitances (107–325 F/g) compared with bare RGO (55 and 37 F/g) at a potential scan rate of 20 mV/s. Furthermore, it is obtained that the specific capacitances of the composite electrodes based on hollow porous gold nanoparticles are larger than those of previously reported supercapacitors with spherical gold nanoparticles/graphene as electrode materials. The improved electrochemical properties of the HPAuNPs/RGO/GC nanocomposite electrodes can be ascribed to the hollow and porous structure of the gold particles on RGO sheets.

Facile synthesis of BiSI and Bi13S18I2 as stable electrode materials for supercapacitor applications

In this paper, we demonstrate a novel synthetic route of two bismuth chalcogenide materials 3-D hexagonal Bi13S18I2 and 3-D orthorhombic BiSI, and investigate their potential as the active electrode material for supercapacitors.

Hydrothermal Synthesis of Three-Dimensional Perovskite NiMnO3 Oxide and Application in Supercapacitor Electrode

Supercapacitors are attractive as a major energy storage device due to their high coulombic efficiency and semi-permanent life cycle. Transition metal oxides are used as electrode material in supercapacitors due to their high conductivity, capacitance, and multiple oxidation states. Nanopowder transition metal oxides exhibit low specific surface area, ion diffusion, electrical conductivity, and structural stability compared with the three-dimensional (3D) structure. Furthermore, unstable performance during long-term testing can occur via structural transition. Therefore, it is necessary to synthesize a transition metal oxide with a high specific surface area and a stable structure for supercapacitor application. Transition metal oxides with a perovskite structure control structural transition and improve conductivity. In this study, a NiMnO3 perovskite oxide with a high specific surface area and electrochemical properties was obtained via hydrothermal synthesis at low temperature. Hydrothermal synthesis was used to fabricate materials with an aqueous solution under high temperature and pressure. The shape and composition were regulated by controlling the hydrothermal synthesis reaction temperature and time. The synthesis of NiMnO3 was controlled by the reaction time to alter the specific surface area and morphology. The prepared perovskite NiMnO3 oxide with a three-dimensional structure can be used as an active electrode material for supercapacitors and electrochemical catalysts. The prepared NiMnO3 perovskite oxide showed a high specific capacitance of 99.03 F·g−1 and excellent cycle stability with a coulombic efficiency of 77% even after 7000 cycles.

Pencil Peel Derived Highly Porous and Conductive Activated Carbon for All-Solid-State 1.8 V Symmetrical Supercapacitors

Activated carbon recycled from biomass resources are recently gaining attention for variety of applications due to their tunable pore size, high specific surface area and good electrical conductivity. Herein, we have synthesized highly porous and conductive activated carbon using commonly available and recyclable pencil peels. The pencil-peel derived activated carbon (PDAC) shows very high specific surface area and good conductivity, therefore becomes suitable to be used as an active electrode material for supercapacitors. The PDAC material is obtained at different temperatures viz. 700, 800 and 900 °C. Among them PDAC-800 shows highest specific surface area and hierarchal pore size while maintaining good conductivity. Due to these properties, PDAC-800 based electrode shows enormous electrochemical performance as compared to its other counterparts. The PDAC-800 electrode possesses high specific capacitance of 552.5 F/g at a current density of 1 A/g using 1 M H2SO4 aqueous electrolyte. Furthermore, an PDAC-800//PDAC-800 based all solid-state flexible symmetrical supercapacitor is assembled using two equally weighted PDAC-800 electrodes, which shows a wide potential window of 1.8 V. Therefore, the as fabricated solid-state device delivers a high energy density of 25.7 Wh/kg with a high-power density of 939.6 W/kg. Meanwhile, the device shows a long-term cycle life of 92.2 % after 5000 continuous charge-discharge cycles. A PDAC-800 based supercapacitor device in PVA-1 M H2SO4 polymer gel electrolyte with 1.8 V potential window is capable to power up a white LED for 3 minutes upon charging for 40 seconds. This work paves the way for the next generation energy storage technology and demonstrate its potential for future supercapacitor application.

Electrochemical Studies of One-Pot Synthesized Tetragonal Hausmannite Manganese Oxide/ Nitrogen-Doped Reduced Graphene Oxide Nanohybrid for Supercapacitor Applications

The increasing consumption of fossils fuel accompanied by related carbon emissions and complex set of issues associated with the generation and use of electricity has raised an urgent need for reliable, renewable and sustainable energy alternatives [1]. Remarkable progress made in nanoscience and nanotechnology brought inspiration for further development of new technologies in electrochemical energy storage. Supercapacitors (SCs) have emerged as a fast-rising class of energy storage technology and have received tremendous attention for potential applications in high-power sources [1,2]. Thus, manipulation of nanostructured materials became an important approach for the improvement of energy storage properties in SCs. Up to now, various synthetic methods have been established to improve the electrode materials for SC applications. Carbon nanomaterials such as carbon nanotubes (CNTs), graphene and graphene oxide (GO) have been widely used and modified to enhance their energy storage performance in SCs. Recently, much interest has been devoted to the doping of carbon materials to improve the performance of SC devices. Manganese oxide-based electrode materials characterized by their high theoretical specific surface area (1370 m2 g-1), high theoretical specific capacitance (1100 to 1300 F g-1), low-cost, abundance and environmentally friendly in nature, have attracted significant interest as active electrode materials for SCs. Although intensive study has been done on the MnO2-based pseudocapacitor, tetragonal hausmannite manganese oxide, Mn3O4, has received limited attention in SCs application [3]. Among various synthetic methods of synthesizing carbon/metal oxides nanohybrids, hydrothermal reduction of metal salts in the presence of carbon material is widely used, due to the simple operation and the low cost. This work present, one-pot synthesis of nitrogen-doped reduced graphene oxide decorated with hausmannite manganese oxide (N-rGO/Mn3O4 nanohybrid) and the study of its electrochemical energy storage performance for supercapacitor application. The microscopic and spectroscopic characterization of N-rGO/Mn3O4 nanohybrid and its precursor materials were acquired using SEM, EDX, Raman and XRD whereas the electrochemical characterization were acquired using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS).

Glycine-assisted hydrothermal synthesis of NiCo2S4 as an active electrode material for supercapacitors

Nickel cobalt sulfide (NCS) was synthesized from nickel and cobalt nitrate (NCS-1) by a hydrothermal method. In another method, nickel cobalt sulfide (NCS-2) was also synthesized from hydrothermally synthesized nickel cobalt oxide (NCO). The syntheses of NCS-1 and NCO were conducted in the presence of glycine as a templating agent. The NCS and NCO samples were thoroughly characterized by different techniques. XRD studies showed that both NCO and NCS consisted of the cubic crystal phases. Cyclic voltammetry of NCO and NCS revealed that, with an increasing scan rate within the range of 10–100 mV s−1, the specific capacitance of the samples reduced. The specific capacitance of NCS-2, measured by galvanostatic charge–discharge, was found to be 675 F g−1, which is higher than those of NCO (313 F g−1) and NCS-1 (500 F g−1). The specific capacitance retention of NCS-2 was 88% over 1000 cycles, indicating the good cyclic stability of the material.

Carbon electrodes with double conductive networks for high-performance electrical double-layer capacitors

Tremendous efforts have been devoted to develop the active materials for supercapacitor electrodes, but very few are focused on the improvement of the electrode material/electrolyte interfaces via protonic conductors. In this study, double conductive networks are constructed in powdery carbon electrodes by using sulfated zirconia as protonic conductor and acetylene black as electric conductor. The synergetic effect of protonic and electric double transport pathways enhances the electrode material/electrolyte interfaces, reduces diffusion distance of protons, and increases the electrode specific capacitance. Compared to the control electrode without protonic conductor, the electrode shows a specific capacitance with 21.0% increment. The proposed strategy may be a promising avenue for preparation of powdery carbon electrodes used in electrical double-layer capacitors.

One-dimensional MoO3/Pd nanocomposite electrodes for high performance supercapacitors

One-dimensional (1D) nanostructures are the exemplary host for fabricating active electrode material for supercapacitors as they have large specific surface area, robust adsorption/desorption capability and outstanding thermal stability, which could assist as support and promoter to anchor noble metal nanoparticles with enhanced electrochemical properties. Herein, pure and MoO3/Pd nanocomposites have been synthesized by simple hydrothermal method. The XRD spectrum of synthesized powder exhibited orthorhombic α-MoO3 structure and the calculated average crystallite sizes are 42 nm and 33 nm for pure and MoO3/Pd nanocomposites respectively. The Pd nanoparticles plays a crucial role in controlling the structure. The SEM images showed 1D nanorods like structure with a size of about 100 nm dia and few micrometer length. The TEM images confirm the Pd nanoparticles are incorporated into the 1D MoO3 nanorods. The electrochemical properties of pure and MoO3/Pd 1D nanocomposite electrodes showed pseudocapacitive nature. The MoO3/Pd electrode exhibited high specific capacitance of 501 F g−1 at a current density of 1 mA g−1 with good cycling stability. The high specific capacitance of newly fabricated MoO3/Pd nanocomposite electrode is mainly associated with the synergetic effect between Pd nanoparticles and MoO3 nanorods.

Controlled synthesis of SnO2@NiCo2O4/nitrogen doped multiwalled carbon nanotube hybrids as an active electrode material for supercapacitors

A thermal reduction process was successfully employed to construct novel hybrid composites of SnO2@NiCo2O4/N-doped multiwalled carbon nanotubes (N-MWCNTs) for supercapacitors. The hybrid confirmation studies were performed using X-ray diffraction, Raman and X-ray photoelectron spectroscopy analyses. Cyclic voltammetry performance confirmed their suitability for use as an active electrode material for supercapacitors. SnO2@NiCo2O4/N-MWCNTs showed the high specific capacitance of ∼728 Fg−1 at 4 A/g in 6 M KOH electrolyte. After 5000 cycles, the hybrid composite produced excellent capacitance retention property with ∼92% of its primary value. Consequently, this SnO2@NiCo2O4/N-MWCNTs hybrid composite promising electrode for high-performance supercapacitor applications.

Ordered mesoporous Co3O4/CMC nanoflakes for superior cyclic life and ultra high energy density supercapacitor

Development of micro/nanoarchitectures with unique morphology and size remains a great challenge in the pursuit of electrochemically active electrode materials for supercapacitors. Ordered mesoporous, flaky structures have been achieved by combined species (Co3O4/CMC) to meet the energy necessities in supercapacitors. Present study suggests an energy budget approach to address the preparation of cobalt oxide (electrical conductivity) with remarkable enhanced electrochemical performance by utilizing carbon (carboxymethyl cellulose-CMC) as physical support. This structure also offers short diffusion path for ions and accelerate effective charge transport which results in high specific capacitance (298 C g−1 at 1 A g−1), outstanding stability (90% capacity retention after 5000 cycles) and low charge transfer resistance (0.5 Ω) in three electrode system. In addition, we have designed an asymmetric supercapacitor (operating voltage 0–1.2 V) which shows desirable electrochemical behavior with an energy density of 18 W h kg−1 (at 2 A g−1). These outcomes endorse the potential capabilities of integrated Co3O4 & CMC which could be a promising electrode in future generation supercapacitors.

Quantitative characterization of a voltage-dependent pseudocapacitance on heteroatom-enriched nanoporous carbons

Nanostructured carbons with a number of redox-active sites play a key role as active electrode materials for supercapacitors and rechargeable batteries, owing to their pseudocapacitive charge storage behaviors. Nevertheless, there is currently no method to characterize the level of contribution of pseudocapacitance in overall capacitance values, hindering technological and scientific advancement of pseudocapacitive electrode materials. In this study, we can observe the voltage-dependent pseudocapacitive behaviors of heteroatom-enriched nanoporous carbons, which can be detected through a simple comparison of electrochemically obtained results in both aqueous and organic electrolyte systems. It is also confirmed that the voltage-dependent pseudocapacitive behaviors are so fast and stable that the heteroatom-enriched nanoporous carbons based on the voltage-dependent pseudocapacitive behaviors can deliver high specific energy and power as cathodes when they are assembled with a proper counterpart anode.

Cuprous oxide nanocubes decorated reduced graphene oxide nanosheets embedded in chitosan matrix: A versatile electrode material for stable supercapacitor and sensing applications

Herein, we report cuprous oxide nanocubes decorated reduced graphene oxide (CNC-rGO) immersed in chitosan matrix as a versatile and enhanced electrochemically active electrode material for both supercapacitor and hydrogen peroxide (H2O2) sensor applications. The CNC-rGO was synthesized by one-pot scalable chemical precipitation method. The morphology and crystal structure of as-synthesized hybrid material was characterized by field emission scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The CNC-rGO hybrid material immersed in the chitosan matrix was used as an enhanced electrochemically active electrode material for supercapacitor and hydrogen peroxide (H2O2) sensor. The fabricated CNC-rGO hybrid in chitosan matrix as an electrode showed remarkable charge storage capacity of 772.3Fg−1 (12.87mAhg−1) at a current density of 0.2Ag−1 with high cyclic stability over 2000 charge-discharge cycles. Similarly, H2O2 sensing performance of the same electrode exhibits very high sensitivity of 0.33AM−1cm−2 within a linear range of detection of 20–160μM. Thus, the synthesized CNC-rGO hybrid material composed of numerous cuprous nanocubes on rGO nanosheets with large active sites showed enhanced electrochemical activity beneficial towards the supercapacitor and H2O2 sensor applications.

Facile fabrication of Ag/PANI/g-C3N4 composite with enhanced electrochemical performance as supercapacitor electrode

Ag nanoparticles decorated Polyaniline (PANI)/graphitic carbon nitride (g-C3N4) composite was fabricated as active electrode materials for supercapacitors via an in-situ oxidative polymerization. Morphology and structure of Ag/PANI/g-C3N4 composite were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) and X-ray diffraction (XRD). The supercapacitive behavior of the electrode material was tested in a three electrode system using 1.0 M H2SO4 electrolyte. The results indicated that the Ag/PANI/g-C3N4 composite delivered a high specific capacitance of 797.8 F g−1 and an excellent capacitance retention of 84.43% after 1000 cycles at an applied current density of 1 A g−1. Ragone plot was derived and compared which showed enhanced supercapacitive performance of Ag/PANI/g-C3N4. The composite should be ideal potential electrode materials for high-performance and effective supercapacitors.

Nitrogen-doped hierarchical porous carbon using biomass-derived activated carbon/carbonized polyaniline composites for supercapacitor electrodes

Biomass porous micro/nanostructures activated carbon materials have attracted tremendous attention in the field of energy storage due to their high specific surface area, excellent electrical conductivity, low cost and environmental benignity. In this paper, we innovatively use celery as a biomass carbon precursor to prepare nitrogen-doped hierarchical porous carbon materials by activation, polymerization and carbonization. Prepared Celery-derived activated carbon is utilized to synthesize activated carbon/polyaniline composite material by wet-chemistry method and further carbonized to obtain nitrogen-doped hierarchical porous carbon. The nitrogen-doped hierarchical porous carbon materials are used as the active electrode materials for supercapacitors. It exhibits high specific capacitance of 402 F g−1 in 1 M H2SO4 electrolyte at 1 A g−1. After 10,000 GCD cycles, material still displays cycling stability of 97% capacitance retention. The outstanding electrochemical performance endows nitrogen-doped hierarchical porous carbon with enormous prospects as a supercapacitor electrode material.