Potential Supercapacitor Research Articles

Three-dimensional self-doped hierarchical porous mussel nacre-derived carbons for high performance supercapacitors

A facile self-doping and self-templating strategy to prepare three-dimensional nitrogen-doped hierarchical porous carbons via direct carbonization of mussel nacre (MN) is developed. Self-templating can be effective to retain the origin structure and the volatile organic components can serve as carbon precursors for porous carbon. The typical MN-derived carbon (MNC) carbonized at 800 °C is endowed with high surface area of unique hierarchical porosity (consisting of macropores, mesopores and micropores), and high content of heteroatom functionalities (1.30 at.% N). Consequently, the performance in the alkaline KOH electrolyte system was particularly promising with the MNC-6 electrodes showing a high capacitance of 243.7 F g−1 at a current density of 1.0 A g−1 and a promising cycling stability with 85.7% capacitance retention at 1.0 A g−1 after 10,000 cycles. The present work provides a new avenue for facile and high efficient construction of N-doped hierarchical porous carbons for potential supercapacitor.

Decoupling and correlating the ion transport by engineering 2D carbon nanosheets for enhanced charge storage

The high aspect ratio of two-dimensional (2D) carbon materials feature unique superiorities and great potential in supercapacitors. The transport of electrolyte ions inside the 2D carbon electrode that can directly affect the overall electrochemical performance, is a key issue that need to be concerned. Nevertheless, the research regarding this process always lags far behind the material concerns and the intrinsic factors to affect ion transport remain obscure. Here we for the first time focus on and correlate the potential and possible factors for addressing this issue using 2D porous carbon nanosheets with tunable thickness as representative demos. A compromise balance between the thickness and ion transport behavior is presented and investigated. The optimal thickness of nanosheets can effectively avoid curling and stacking of ultrathin nanosheets, shorten the distance of ion transport and accelerate the ion diffusion, which render the material with the low resistance corresponding to minimum Warburg coefficient and maximum ion diffusion coefficient for fast transport of electrolyte. A superior capacitance value of 280 F g−1 can be obtained at 0.5 A g−1, with a retention rate of 81% even at a large current density of 100 A g−1. Besides, the symmetric supercapacitor with 1-ethyl-3-methylimidazolium tetrafluoroborate electrolyte (EMIMBF4) delivers an energy density of 94 Wh kg−1 at 1.8 kW kg−1. This work illustrates the importance for transferring the focus from carbon materials to electrolyte ion transport behavior within electrode and provides a guidance for regulating the ion transport by engineering the microscopic thickness of advanced materials in energy-related fields.

Nonaqueous, Redox‐Active Gel Polymer Electrolyte for High‐Performance Supercapacitor

Redox‐active liquid or polymer‐based aqueous electrolytes are widely reported in carbon‐based supercapacitors, enhancing their performance substantially due to the involvement of fast redox reaction(s) at the electrode–electrolyte interface. Here, a nonaqueous, ionic liquid (IL)‐based redox‐active gel polymer electrolyte (GPE) as a potential supercapacitor electrolyte is demonstrated. This electrolyte, comprising IL 1‐butyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide added with redox agent NaI, immobilized in poly(vinylidenefluoride‐co‐hexafluoropropylene), offers excellent thermal, mechanical, and electrochemical stability with high ionic conductivity of ≈3.81 × 10−3 S cm−1at room temperature. The redox‐additive NaI not only increases the ionic conductivity of electrolyte but also introduces redox behavior at the interfaces of porous activated carbon supercapacitor resulting in high specific capacitance (≈334 F g−1) and high specific energy and power (≈26.1 and ≈18 kw kg−1, respectively). The capacitor with redox‐active nonaqueous GPE offers stable performance up to 10 000 charge–discharge cycles with ≈5% initial fading only. This study opens a novel approach to prepare highly stable redox‐active GPEs for high‐performance supercapacitors.

Facile synthesis of interconnected carbon network decorated with Co3O4 nanoparticles for potential supercapacitor applications

Three-dimensional (3D) multifunctional carbon nanofibers (CNFs) are promising electrode materials of electrochemical energy storage devices for their unique interconnect structures. Here, we prepared interconnected carbon network decorated with Co3O4 nanoparticles by a facile soak-adsorption strategy. Among them, bacterial cellulose (BC) with inherent interconnect structures was used as carbon precursor. The adsorbed organophosphorus pesticides can introduce new functional groups on the surface of BC and create loose structure for fabricating a loose 3D CNFs skeleton. The absorbed cobalt salt transformed into Co3O4 nanoparticles which anchored on the CNF skeleton to obtain CNFs/Co3O4 composites. This strategy combines interconnected CNFs and uniformly distributed Co3O4 nanoparticles which provide large specific surface area, fast electron transport, well mechanical stability and high electrochemical activity. The CNFs/Co3O4 electrode exhibits a high specific capacitance (785 F g−1 at 0.5 A g−1), superior rate performance (capacity remained 57% from 0.5 to 20 A g−1) and good cycling stability (over 93.0% capacity retained after 5000 cycles). Furthermore, the assembled asymmetric device CNFs/Co3O4//activated carbon (AC) possesses a high energy density of 13 Wh kg−1 at the power density of 257 W kg−1 and the performance still retains 85.9% of initial capacity after 10,000 cycles.

Electrochemical Effects of Annealing Temperature on Anodic 304 Stainless Steels

Supercapacitors, as an energy storage device, have attracted growing interests [1]. Recently, iron oxides (a-Fe2O3 and Fe3O4) have been demonstrated to present comparable pseudocapacitive properties [2]. It was further observed that nanoporous oxide layers have been obtained on various SS substrates by electrochemical anodization process. They can provide more reaction sites due to high surface area, and acceptable electron conductivity due to multiple valence states of formed Fe3O4 for potential supercapacitor electrodes. Meanwhile, it has been envisaged that annealing at various temperatures may induce morphologgical modification and crystal-phase transition, which will strongly influence the supercapacitance behavior [3]. However, the effects of annealing temperature on supercapacitance behavior of anodic oxide films have not been well studied. In the experiments, SUS 304-type SS foils were used as the anode for prorous formation. The anodization of SS foils was carried out in ethylene glycol containing 0.1 M distilled water and 0.1 M NH4F using a two-electrode cell. The SS foils worked as anode and graphite plate as cathode. During the anodization process, the long-term anodization was kept by slightly decreasing electrolyte temperature to rescrict the temperature rise. The as-fabricated samples were soaked in 99.9% ethanol for 1 h followed by annealing at 200-600℃ in air for 3h, respectively. Fig.1 presents the SEM images of self-organized porous anodic films formed on the surface of SS foils by constant potential anodization of 50 V for 1 h, respectively annealed at 200-600℃ in air. The self-organized pores exhibited a quasi-honeycomb structure with pore diameters ranging from 45 to 60 nm as shown in Fig. 1a. As shown in Fig. 1b, the thickness of 8.12 μm anodic layer was formed at 50 V for 1h and some cracks were further clearly observed across the anodic films by the residual stress produced during film growing process and further amplified during subsequent annealing process. Remarkably, the decrease of the pore size from the top to the bottom of the porous anodic film was clearly observed by SEM pictures shown in Fig. 1c, the pore size varies from 53±10nm (top) to 33±7nm (bottom). An anodic etching model will be applied to explain the phenonomenon. XRD spectra further reveals the annealed anodic films own crystalline structures, which are predominantly composed of three phases of hematite (Fe2O3), eskolaite (Cr2O3) and spinel (Fe3O4 and FeCr2O4), which was clearly increased with the increasing annealing temperature. Fig. 2 (a) shows the C-V curves of the anodic layers formed at different annealing temperature. When tested as a binder-free electrode, all C-V curves exhibit a nearly symmetric CV plots, indicating good reversibility of faradaic redox reactions. Clearly, the anodic layer annealed at 400℃ exhibits the maximum specific area capacitance among the five samples, which can be explained by the increased amount of Fe2O3 and Fe3O4. Fig. 2 (b) shows the C-V curves of the anodic layers (400℃) recorded at the scan rates from 5 to 100 mV s-1. The enclosed area under the CV curve increases with the scan rate increases from 5 to 100 mV s-1. Similar results were observed in GCD plots as shown in Fig. 2 (c) and (d). The anodic layers exhibit the specific area capacitance ~ 54.5, 145.3, 80.6 and 18.3mF cm-2 at 1 mA cm-2, resepectively for the annealing temperature from 300-600℃. The optimum one exhibited the higher area capacitance ~ 145.3 mF cm-2 at 1 mA cm-2 and ~ 76 mF cm-2 at 4 mA cm-2, and the capacitance still retained 53.3% of its initial value after 1000 cycles. The Nyquist plots are presented in Fig. 2e to assess the resistance and capacitance of the formed anodic films. The lower resistance of anodic film annealed at 600℃ was attributed to the increased amount of high conductive Fe3O4. In summary, nanostructured anodic films have been fabricated on 304 stainless steel via constant-potential anodization instead of galvanostatic anodization. The supercapacitance behavior of anodic film is strongly dependent on the annealing temperature. When tested as a binder-free electrode, the optimum anodic layers (400℃) exhibit the highest area capacitance ~ 145.3 mF cm-2 at 1 mA cm-2, and the capacitance still retained 53.3% of its initial value after 1000 cycles.

Evaluation of Nanoporous Carbon Synthesized from Direct Carbonization of a Metal⁻Organic Complex as a Highly Effective Dye Adsorbent and Supercapacitor.

The synthesis of interconnected nanoporous carbon (NPC) material from direct annealing of ultra-small Al-based metal–organic complex (Al-MOC) has been demonstrated. NPC presents a large accessible area of 1054 m2/g, through the Methylene Blue (MB) adsorption method, which is comparable to the high specific surface area (SSA) of 1593 m2/g, through an N2 adsorption/desorption analysis. The adsorption properties and mechanisms were tested by various dye concentrations, pH, and temperature conditions. The high MB accessible area and the good electrical conductivity of the interconnected NPC, led to a large specific capacitance of 205 F/g, with a potential window from 0 to 1.2 V, in a symmetric supercapacitor, and a large energy density of 10.25 Wh/kg, in an aqueous electrolyte, suggesting a large potential in supercapacitors.

Co3O4@NiCo2O4 microsphere as electrode materials for high-performance supercapacitors

In this work, hierarchical Co3O4@NiCo2O4 microspheres composed of nano particles grown on nickel foam as supercapacitor electrode material were designed by a hydrothermal route, following an ultrasonic-assisted process. The introduction of moderate amounts NiCo2O4 in Co3O4 can decrease charge transfer resistance and enhance the transfer of electrons and ions. Therefore, Co3O4@NiCo2O4 (4:1) shows an excellent specific capacitance of 879.4 F g−1 at 10 A g−1, and the capacitance retention maintains 81.2% of its first capacitance after 3000 cycles, indicating a high cycling durability and outstanding fast charge-discharge performance. The outstanding property exhibits that the hierarchical Co3O4@NiCo2O4 (4:1) microsphere has tremendous application potential in supercapacitors.

A simple and practical hybrid ionic liquid/aqueous dual electrolyte configuration for safe and ion-exchange membrane-free high cell potential supercapacitor

A simple and practical hybrid dual ionic liquid (IL)/1.0 M LiTFSI(aq.) is proposed using ILs in the nanopores of activated carbon for high cell potential supercapacitor. Unlike previously reported system, the proposed supercapacitors use no ion-exchange membrane, a low quantity of ILs (∼20 μL/cell) and a simple coin cell (single compartment). Hydrophilic and hydrophobic ILs were tested in the hybrid dual electrolyte configuration. The dual electrolyte with hydrophobic ILs enables the maximum operational cell potential of 2.2 V with the excellent capacitance retention of 94% after continuous charge-discharge cycles up to 30,000 at 0.5 A g−1. The identified maximum cell potential is higher than the previously reported value of 1.9 V for the supercapacitors with the dual electrolyte comprising an ion-exchange membrane and, also comparable with the supercapacitors using “water-in-salt” electrolytes (2.2 V). The supercapacitor cell using proposed hybrid dual IL/aqueous electrolyte delivers the specific capacitance of 34.0 F g−1 and the specific energy of 22.0 Wh kg−1. The proposed hybrid dual IL/aqueous electrolyte may be useful for many energy storage devices requiring high cell potentials.

Molten Salt Synthesis of Na‐Mn‐O Composites as Electrode Materials for High‐Performance Supercapacitors

AbstractManganese (Mn) based oxide materials are regarded as one of the favorable electrode materials, exhibiting a high energy density, low‐cost and environmental benignity. In this work, we focus on synthesizing hollandite Na−Mn−O composites as potential supercapacitor electrode materials by a facile molten salt technique. The structure and the morphology of the Na−Mn−O system were significantly influenced by the synthesis temperature. The Na−Mn−O composite synthesized at 550 °C (Na−Mn−O 550) demonstrates a distinct structure and a mixed morphology of nanorods and nanoparticles. The Na−Mn−O 550 composite exhibits the best electrochemical performance with 306.0 F/g at 0.5 A/g and maintains 80.7 % capacity after 3000 charge‐discharge times at 5 A/g. The largest specific capacitance of 64.0 F/g (0.3 A/g) and high energy density of 20.0 Wh/kg (226.1 W/kg) were achieved in the assembled asymmetric supercapacitor device based on the Na−Mn−O 550 and active carbon. Moreover, a long‐cycling lifetime with 92.9 % retention after 10000 cycles was performed, which holds broad prospect for practical application in high performance energy storage devices.

Evaluation of cobalt nanoparticle deposited graphene oxide and carbon nanotube supports as supercapacitor electrodes

Cobalt nanoparticles were deposited on multi-wall carbon nanotubes (CNT) and graphene oxide (GO) carbon supports and evaluated as a potential supercapacitor electrodes. The structure and morphology of the cobalt nanoparticles deposited on carbon supports were studied using XRD, TGA, and Raman spectroscopy. Cyclic voltammetry was used to measure the electrical charge of the electrode based on the materials and their specific capacitance (Csp) were calculated. GO based electrode showed a higher Csp than CNT electrode which is attributed to a larger surface area of the GO carbon support. Interestingly, the deposition of Co nanoparticles promoted an enhanced Csp in the both GO and multi-wall CNT supports.

Conversion of laboratory paper waste into useful activated carbon: a potential supercapacitor material and a good adsorbent for organic pollutant and heavy metals

In this study, laboratory tissue paper and hardboard waste were utilized to synthesize activated carbon (AC). The structure, morphology, zeta potential and particle size of the synthesized AC is investigated using X-ray diffraction, scanning electron microscopy-energy dispersive spectroscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, zeta seizer and particle size analysis techniques. The synthesized AC is used as an adsorbent for removal of Methylene blue (MB) and chromium ion from aqueous solution. AC adsorption efficiency is analyzed using a UV–Vis spectrophotometer. The adsorption capacity of the tissue paper derived activated carbon (T-AC) is greater than that of the hardboard derived activated carbon (H-AC). MB adsorption by T-AC and H-AC data fitted well to the Langmuir isotherm model. The thermodynamic parameters such as Gibbs free energy (∆G), enthalpy change (∆H) and entropy change (∆S) are calculated for both the T-AC and H-AC adsorbents. Moreover, the dye adsorbed T-AC and H-AC exhibit good specific capacitance value of about 260 Fg−1 and 155 Fg−1 at a constant current density of 0.5 Ag−1. The specific capacitance is maintained to an extent of 92% and 71% even after 1000 cycles for T-AC and H-AC respectively. It is encouraging that the results obtained have opened up ways of utilizing laboratory waste materials for producing materials useful in environmental remediation and energy storage sectors.

Electrochemical performance of two-dimensional Ti3C2-Mn3O4 nanocomposites and carbonized iron cations for hybrid supercapacitor electrodes

In this work, we present a simple two-step synthesis route to develop a cost effective high performance Ti3C2Mn3O4 nanocomposite via a solvothermal process at 150 °C. The characterization of the composite material was obtained via various techniques. Electrochemical performance study of the material as a potential supercapacitor electrode demonstrated a maximum specific capacity of 128 mAh g−1 at a specific current of 1 A g−1 in a 6 M KOH aqueous electrolyte. A capacity retention of 77.7% of the initial value was recorded after over 2000 galvanostatic cycles at 10 A g−1 for the single electrode. More so, the as-prepared nanocomposite sample electrode also showed a relatively stable property with an energy efficiency of 83.5% after cycling tests. Interestingly, an assembled hybrid supercapacitor device with carbonized iron cations (C-FP) and the Ti3C2Mn3O4 composite delivered a specific capacity of 78.9 mAh g−1. The device yielded a high energy of 28.3 Wh kg−1 with an equivalent 463.4 W kg−1 power densityat 1 A g−1. A good cycling stability performance with an energy efficiency of 90.2% in addition to a 92.6% capacity retention was observed for over 10,000 cycles at specific current of 3 A g−1 over a voltage window of 1.5 V.

One pot facile synthesis of carbonaceous gel via thiol-epoxy click reaction as potential electrode material for supercapacitor

Carbonaceous gels, as afresh materials are gaining considerable attention in recent era because of their multifunctional characteristics. Benefiting from these characteristics, a facile and template free in-situ pathway is developed for the fabrication of carbonaceous gel as a source of porous carbon material for potential supercapacitor applications. The as prepared carbonaceous gel was then chemically activated by KOH, which introduces compact porous structure to the gel as revealed by scanning electron microscopic (SEM) analysis. The activated gel is then converted into activated microporous carbon (AMC) via simple pyrolysis at 800 °C under inert atmosphere. The obtained AMC shows excellent performance as an electrode material for supercapacitors. The AMC electrode exhibited high specific capacitance value of 310 F g−1 at a current density of 0.2 A g−1 in 6 M KOH as an electrolyte solution using potential window from -1 to 0 V. Furthermore, the AMC possesses excellent cycle stability up to 99.4% of the retention of capacitance for almost 10,000 charging and discharging cycles. These outcomes consolidated that inexpensive carbonaceous gels are potential candidate to fabricate electrode for various energy storage devices.

A general method to fabricate MoO3/C composites and porous C for asymmetric solid-state supercapacitors.

MoO3 is one of the most promising electrodes for high energy density supercapacitors due to its layered structure, which facilitates the insertion/removal of small ions. However, the commercial recognition of MoO3-based electrodes has been hampered by their low electronic conductivity, poor structural stability and narrow working potential window. A MoO3/C composite (MCs) has been synthesized by a polymerization method followed by calcination of the obtained hydrogel. The obtained MCs electrode exhibits remarkable electrochemical performance in both aqueous (432.5 F g−1 at a current density of 0.5 A g−1, 100% capacity retention after 10 000 cycles) and all-solid (220.5 F g−1 at 0.5 A g−1) systems with porous C as the positive electrode, demonstrating its potential in commercial utilization.

Creating binder-free supercapacitor electrodes from biomass resources: a nitrogen-doped pomelo peel derived carbon foam

We conducted experiments in producing nitrogen-doped carbon foam using pomelo peels as a raw material. Pomelos are a citrus fruit similar in appearance to grapefruit, and native to South and Southeast Asia. Specifically, we fabricated nitrogen-doped pomelo peel derived carbon foam (N-PPCF) by using an ammonia gas treatment. The as-prepared N-PPCF had a high specific surface area of 1,218.5 m2 g−1, an average pore size of 1.36 nm, and a pore volume value of 0.50 cm3 g−1. Additionally, the N-PPCF had a nitrogen content of 8.1%, allowing for a high specific capacitance of 150.1 F g−1 at a density of 1.0 A g−1. Even at 4 A g−1, the N-PPCF still maintained an ideal capacitance of 115.6 F g−1. Ultimately, we believe that nitrogen doped carbon foam is a potential method for treating pomelo peels, and that N-PPCF can function as a potential binder-free supercapacitor electrode.

Porous Activated Carbons Derived from Pleurotus eryngii for Supercapacitor Applications

Varieties of natural biomass have been utilized to prepare porous carbon materials for supercapacitor applications. In this work, porous activated carbons derived from Pleurotus eryngii were prepared by carbonization and KOH activation. The activated carbons presented a large specific surface area of 3255 m2·g−1 with high porosity. The as-prepared electrode exhibited a maximal specific capacitance of 236 F·g−1 measured in a three-electrode cell system. Furthermore, the assembled symmetric supercapacitor showed a specific capacitance of 195 F·g−1 at 0.2 A·g−1 and a superior specific capacitance retention of about 93% after 15000 cycles. The desirable capacitive behavior suggests that Pleurotus eryngii is an attractive biomass source of carbon materials for the potential supercapacitor applications.

Direct synthesis of graphene-based hybrid films as flexible supercapacitor electrodes

Excellent carbon nanotubes and graphene have attracted more and more attention due to their fascinating properties of combining advantages. In this report, graphene/multi-walled carbon nanotube composite films (G/MWNTs) with excellent mechanical flexibility and high electrical conductivity were prepared by one-step and self-assembly strategy. Importantly, G/MWNTs were equipped with high specific surface areas, which are conductive to growing the micropores and active sites. The electrochemical measurement results indicate that G1/MWNTs exhibit a specific capacitance of 249.3 F g−1 at a current density of 200 mA g−1 and still remain 91.3% of the original specific capacitance after 8000 cycles, indicating an excellent electrochemical performance. Furthermore, the flexible and mechanically stable graphene-based films can be bent to various angles on demand, which is a necessary condition in practical application. The as-prepared G/MWNTs show enormous potential in supercapacitors as high performance electrodes and may be favorable for some other research fields as well.

A free-standing, flexible PEDOT:PSS film and its nanocomposites with graphene nanoplatelets as electrodes for quasi-solid-state supercapacitors

Research and development on all-solid-state, flexible supercapacitors is the prime concern of the scientific community these days due to their various advantages including their easy transportability, miniaturization, and compactness in different appliances. We report the novel configuration of all-solid symmetrical supercapacitors employing free-standing, flexible films of poly(3,4-ethylenedioxythiophene) poly(styrene sulfonate) (PEDOT:PSS) and its nanocomposite electrodes with graphene nanoplatelets (GNPs), separated by ionic liquid (IL) (1-ethyl 3-methylimidazolium trifluoromethanesulfonate (EMITf))-based gel polymer electrolyte (GPE) films. The free-standing and flexible form of PEDOT:PSS/GNP nanocomposite films have been prepared via simple mixing of the two counterparts. Scanning electron microscopy, x-ray diffraction, Raman analysis, and thermal and mechanical characterizations have been performed to ascertain the suitability of pristine and nanocomposite PEDOT:PSS films as potential supercapacitor electrodes. The GPE film, comprising of a solution of NH4CF3SO3 (NH4-triflate or NH4Tf) in IL, entrapped in poly(vinylidine fluoride-co-hexafluoropropylene) (PVdF-HFP), is a promising electrolyte due to its high ionic conductivity and sufficient electrochemical stability window. The supercapacitor with a PEDOT:PSS nanocomposite containing ∼3.8 wt.% of GNP has been found to give an optimum specific capacitance of ∼106 F g−1 (evaluated from electrochemical impedance spectroscopy), and specific energy and power of ∼6.95 Wh kg−1 and 2.58 kW kg−1, respectively (evaluated from galvanostatic charge–discharge). More importantly, the capacitors demonstrate stable performance for more than 2000 charge–discharge cycles, with only ∼10% initial fading in capacitance. Interestingly, the PEDOT:PSS/GNP nanocomposite-based solid-state supercapacitors with the IL-incorporated GPE have shown comparable (even better) performance than other reported PEDOT:PSS-based supercapacitors.

A Novel Radiation Method for Preparing MnO₂/BC Monolith Hybrids with Outstanding Supercapacitance Performance.

A novel facile process for fabrication of amorphous MnO2/bamboo charcoal monolith hybrids (MnO2/BC) for potential supercapacitor applications using γ-irradiation methods is described. The structural, morphological and electrochemical properties of the MnO2/BC hybrids have been investigated using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS) techniques. The combination of BC (electrical double layer charge) and MnO2 (pseudocapacitance) created a complementary effect, which enhanced the specific capacitance and good cyclic stability of the MnO2/BC hybrid electrodes. The MnO2/BC hybrids showed a higher specific capacitance (449 F g−1 at the constant current density of 0.5 A g−1 over the potential range from –0.2 V to 0.8 V), compared with BC (101 F g−1) in 1 M of Na2SO4 aqueous electrolyte. Furthermore, the MnO2/BC hybrid electrodes showed superior cycling stability with 78% capacitance retention, even after 10,000 cycles. The experimental results demonstrated that the high performance of MnO2/BC hybrids could be a potential electrode material for supercapacitors.

Value added porous carbon from leather wastes as potential supercapacitor electrode using neutral electrolyte

Abstract Leather industries produce a large quantity of chromium containing wet blue leather solid waste (WBW), that are either thrown away or dumped in open lands causing environmental issues. These WBW are biologically resistant as a result of complexation between chromium (III) salts and the carboxyl groups of collagen. The objective of this study is to propose an unusual way to minimize environmental contamination routing through waste to energy concept, adopting cleaner methodologies. The research is also specifically focussed to bring in, new initiatives through interdisciplinary approach serving as a decisive key to transform wet blue leather wastes into a high performance supercapacitor electrode material. Electrochemical measurements such as cyclic voltammetry, galvanostatic charge discharge, and electrochemical impedance spectroscopy techniques using 1 M Na2SO4 aqueous electrolyte were performed to evaluate the suitability of the prepared carbon for supercapacitor applications. Na2SO4, is chosen as it can serve as neutral electrolyte, and has less corrosion behavior. The values of specific capacitance, specific energy, specific power and cycle stability for WBW activated at 900 °C (LSAC9) were 2203 Fg-1, 624.7 Whkg−1, 749.9 Wkg-1 and over 10,000 cycles respectively and are comparable with graphene like carbons. The performance of WBW porous carbons are consequence of micro-meso porosity and graphitic structure and are an initiative of waste to energy storage conversion concepts.