Excellent Supercapacitive Performance Research Articles

New Class of Trimetallic Oxide Hierarchical Mesoporous Array on Woven Fabric: Electrode for high-Performance and Stable battery type Ultracapacitor

Imperative urgency to substitute outdated combustion engines with safer, faster and efficient energy storage devices and conversion systems has inspired researchers to realize new energy storage materials with high performance. In this work, a facile hydrothermal technique with subsequent calcination procedure has been adopted to prepare Cu-Ni-Co (CNCo) based trimetallic oxide nanowires over carbon cloth (CC). Hierarchical mesoporous CNCo arrays on conducting scaffold delivers excellent supercapacitive performance with specific capacitance as high as 2535 Fg-1 at current density of 1 Ag-1 and excellent rate capability of 94% at 5 Ag-1 even after 5000 cycles. To judge the figure of merit of CNCo electrode, results are compared with the synthesized one-dimensional binary and monoxides nanoform over same platform namely nickel cobalt oxide (NCo) and cobalt oxide (Co). Utility of CNCo as robust and potential electrode material is further assessed by fabricating CNCo based symmetric supercapacitor. Specific energy of 39 Wh/kg at specific power of 0.45 KW/kg and extraordinary cyclic stability (capacitance retention more than 100% after 10000 cycles) register from the fabricated device. Coordination of metal ions strengthens the synergistic effect which affects the rate of redox charge transfer and thereby improves the cyclic stability and rate capability.

Ultrahigh specific capacitance of α-Fe2O3 nanorods-incorporated defect-free graphene nanolayers

The development of hybrid materials with high pseudocapacitance and electrical double layer capacitance is an urge for the fabrication of efficient supercapacitor electrodes. Herein, a highly effective, easily performable, high-yielding, and economical method is demonstrated for the preparation of α-Fe2O3 nanorods incorporated defect-free graphene nanosheets that showed excellent supercapacitor performance. α-Fe2O3/graphene nanocomposite has been synthesized by an interlayer catalytic exfoliation of α-Fe2O3 intercalated graphite which showed high conductivity of 3.1 × 106 S/cm. α-Fe2O3/graphene nanocomposite modified carbon paste electrode exhibited ultrahigh specific capacitance values of 1135 mF/cm2 at a scan rate of 5 mV/s and 815 mF/cm2 at a current density of 0.5 mA/cm2. The fast ionic diffusion with no charge transfer resistance of the electrode material was revealed from the electrochemical impedance spectroscopic analysis. α-Fe2O3/graphene nanocomposite showed 100 folds of increase in the specific capacitance compared to α-Fe2O3 and graphene, suggesting their synergistic effect in the nanocomposite leading to a drastic increase in the specific capacitance. The composite displayed good cyclic stability of 79.9% retention of the initial capacitance after 1500 cycles and 54.9% after 10,000 repeated cycles.

High energy density hybrid supercapacitors derived from novel Ni3Se2 nanowires in situ constructed on porous nickel foam

A novel Ni3Se2 nanowires are synthesized in situ on the surface of nickel foam through a one-step hydrothermal reaction under the reaction time of 24 h, and it demonstrates excellent energy storage performance for hybrid supercapacitors.

A {BW12O40} hybrid decorated by Ag+ for use as a supercapacitor electrode material and photocatalyst

Through a hydrothermal method, we successfully synthesized a supramolecular compound [{Ag(phen)2}4{Ag(phen)}2(H2BW12O40)2]. The as-synthesized material exhibited excellent supercapacitive and photocatalytic performances.

Urchin-like NiCo2O4 hollow microspheres with oxygen vacancies synthesized by self-template for supercapacitor

The designed urchin-like NiCo2O4 material exhibits excellent supercapacitive performance due to the hollow porous structure and oxygen vacancies.

An asymmetric supercapacitor with an interpenetrating crystalline Fe-MOF as the positive electrode and its congenetic derivative as the negative electrode

Interpenetrating crystalline Fe-based materials of FeSC and congenetic derivative FeSC# have been assembled into an asymmetric supercapacitor, which can offer an excellent supercapacitor performance.

MoS2/polyaniline/functionalized carbon cloth electrode materials for excellent supercapacitor performance

In this study, molybdenum disulfide (MoS2), polyaniline (PANI) and their composite (MoS2/PANI) were facilely prepared via a liquid-phase method and in situ polymerization. An MoS2/PANI/functionalized carbon cloth (MoS2/PANI/FCC) was facilely constructed by a drop-casting method. MoS2/PANI-10/FCC displays remarkable electrochemical performances, and its specific capacitances varied from 452.25 to 355.5 F g−1 at current densities ranging from 0.2 to 4 A g−1, which were higher than those of MoS2/CC (from 56.525 to 7.5 F g−1) and pure PANI/CC (319.5 to 248.5 F g−1), respectively. More importantly, the MoS2-10/PANI/FCC electrode has a long cycling life, and a capacity retention of 87% was obtained after 1000 cycles at a large current density of 10 A g−1. Moreover, the MoS2/PANI-10/FCC-based symmetric supercapacitor also exhibits excellent rate performance and good cycling stability. The specific capacitance based on the total mass of the two electrodes is 72.8 F g−1 at a current density of 0.2 A g−1 and the capacitance retention of 85% is obtained after 1000 cycles.

Flexible Solid-State Supercapacitors Derived from Biomass Konjac/Polyacrylonitrile-Based Nitrogen-Doped Porous Carbon.

Energy shortage and wasting of resources are two main challenges for human society. To solve these problems, nitrogen-doped porous carbon was synthesized through a simple thermally induced phase separation (TIPS) method with subsequent carbonization and activation with biomass konjac/polyacrylonitrile composites as the raw materials and nitrogen source for the first time. The obtained composite carbon with hierarchical porosity, large specific surface areas, and high content of nitrogen doping shows promise due to its desirable electrochemical performance. Nitrogen-doped porous carbon exhibits a high specific capacitance of 390 F g-1 in a three-electrode system and a good rate characteristic with 70% capacitance retention at 20 A g-1. Excellent stabilization was observed with only a 4.5% capacitance decay under 10 000 cycles at 5 A g-1. The practical application of the composite porous carbon on flexible symmetrical supercapacitors was evaluated, showing a maximum energy density of 9.0 W h kg-1 when the power density was 250.2 W kg-1. More importantly, the fabricated flexible supercapacitor could still keep an excellent supercapacitor performance under bending and shows only a slight capacitance loss of 9% even after 1000 cycles (180°) of repetitive bending. The current study promotes the development of nitrogen-doped carbon materials on flexible energy storage devices.

"One-Step" Carbonization Activation of Garlic Seeds for Honeycomb-like Hierarchical Porous Carbon and Its High Supercapacitor Properties.

In this paper, a simple “one-step” route is introduced to prepare a kind of novel honeycomb-like hierarchical porous carbon (h-HPC) by carbonizing and activating garlic seeds. Due to its special microstructure, h-HPC shows excellent electrochemical properties and high supercapacitor performances. The experimental results reveal the following: (1) There exists an optimal condition for synthesizing h-HPC, i.e., 700 °C carbonization temperature and 1:1 mass ratio of KOH and garlic seeds. (2) h-HPC has a three-dimensional interconnected porous structure and exhibits a specific surface area as high as 1417 m2/g with a narrow pore size distribution. (3) When h-HPC is employed as an electrode material in supercapacitors, its specific capacitance reaches a value up to 268 F/g at a current density of 0.5 A/g and excellent rate capability. (4) The h-HPC-based symmetric supercapacitor shows a high energy density of 31.7 Wh/kg at a power density of 500 W/kg and retains 99.2% of the initial capacitance after 10,000 charge/discharge cycles at 200 mV/s. When compared with similar works, these data are competitive, which demonstrates that the garlic-derived h-HPC is a kind of promising electrode material for the next-generation high-energy-density supercapacitors.

Coal-derived porous activated carbon with ultrahigh specific surface area and excellent electrochemical performance for supercapacitors

Porous activated carbon material is successfully prepared with anthracite through KOH activation. The obtained activated carbon delivers a large specific surface area of 3550.7 m2 g−1 with existence of porous structure. The KOH activation introduces numerous hydroxyl groups on the surface of carbon material, improving the wettability of carbon. As electrode for supercapacitor, the material delivers the high specific capacity of 433 F g−1 at the current density of 0.5 A g−1 and it maintains 230 F g−1 even current density reaches up to 50 A g−1. Especially, as electrode for symmetric capacitor, the porous activated carbon exhibits a high specific capacitance of 280 F g−1 and energy density of 38.9 Wh kg−1 at 0.5 A g−1. The material also displays superior cyclic stability without distinct decay in capacity after 30000 cycles. The porous activated carbon material derived from coal, which embodies characteristics of capacitance behavior, may broaden the horizon of electrode materials and provide application prospect for specialized hybrid supercapacitor applications.

Liquid-phase exfoliation of layered biochars into multifunctional heteroatom (Fe, N, S) co-doped graphene-like carbon nanosheets

• Developing a liquid exfoliation strategy for delaminating multilayered biochars. • The graphene-like carbon nanosheets (Fe-N-S-CNS) had multi-heteroatom co-doping. • Fe-N-S-CNS showed multifunctional electrochemical activity. • A higher ORR activity was obtained than that of commercial Pt/C. • The ionic liquid-based supercapacitor delivered an energy density of 54.1 Wh kg −1 . We here report a liquid-phase exfoliation strategy to delaminate multilayered biochars into multi-heteroatom (Fe, N, S) co-doped graphene-like carbon nanosheets, in which the multilayered biochars derived from naturally evolved layer-by-layer precursors. This strategy provides the versatile capability to tailor the textural properties of the as-synthesized carbon nanosheets, such as obtaining a controllable specific surface area of up to 2491 m 2 g −1 . Thanks to the unique integration of graphene-like microstructures with a thickness of 4.3 nm, large specific surface area and hierarchical pores, homogenous co-doping of N, S, and Fe, and high electronic conductivity, the as-synthesized Fe-N-S co-doped carbon nanosheets could act as multifunctional electrodes for electrocatalytic process of oxygen reduction reaction (ORR) and capacitive energy storage. The optimized nanosheets showed a better ORR catalytic performance than commercial Pt/C catalyst, with a more positive onset potential (1.026 V) and half-wave potential (0.829 V), higher long-term stability, and outstanding methanol tolerance in alkaline mediums. Furthermore, the porous carbon nanosheets exhibited excellent supercapacitive performances which delivered a high energy density of 29.1 Wh kg −1 at a high power density of up to 39.5 kW kg −1 in an ionic liquid electrolyte. This liquid-phase exfoliation strategy will offer new inspiration for the synthesis of various biomass-derived graphene-like carbon nanosheets for multifunctional applications.

Synthesis of NiFeAl LDHs from electroplating sludge and Their excellent supercapacitor performance

This work demonstrated that electroplating sludges (EPS) of specific composition may be used for the synthesis of layered double hydroxide (LDH) materials for energy applications after appropriate treatment. The unique composition and structure of EPS render it with good electrochemical energy storage performance. The EPS containing Ni, Fe, and Al was dissolved by acid and added with urea precipitator. The LDH material was prepared by a facile hydrothermal method. The increase of urea in a certain range is conducive to the formation of intact LDH. However excessive urea levels promoted the transformation from LDH to Ni(HCO3)2. Various active Ni bridged by N in ‒O‒CN promoted electron transfer, ‒O‒CN content in LDHs was proportional to the urea amount. The prepared LDHs exhibited a specific capacitance of 1652.20 F g−1 at 0.5 A g−1, and the value remained at 766.69 F g−1 after 1000 cycles. The prepared LDH has excellent supercapacitor performance, which is closely related to its structure. Therefore, the proposed recycling strategy of EPS resources can be used to prepare LDH supercapacitors, paving the way for new applications of EPS in the field of energy storage.

Synthesis of polypyrrole/nitrogen-doped porous carbon matrix composite as the electrode material for supercapacitors

Polypyrrole complex nitrogen-doped porous carbon matrix (PPy/N-PCM) was synthesized by a simple two-step method. Firstly, graphene oxide was prepared by the modified Hummers method. Secondly, Polypyrrole was compounded on the graphene oxide substrate, and the carbon matrix with a high specific surface area was obtained through high-temperature carbonization and KOH activation, and polypyrrole was used as a nitrogen source for the final nitrogen-doped composite material. The structure characterization of the carbon matrix and the final composite material shows that the carbon matrix surface has obvious porous structure, and the polypyrrole nanospheres grow uniformly on the porous carbon matrix surface. The electrochemical evaluation show that the prepared PPy/N-PCM has excellent supercapacitor performance, and its specific capacitance can reach 237.5 F g−1. When the current density reaches 10 A g−1, it has good cycle stability (the capacitance retention after 1000 charge and discharge is 88.53% of the initial capacitance value, which is better than pure PPy-60.76% and PPy/rGO-C-71.84%). The excellent capacitance performance, good-looking micro-morphology and simple synthesis method of the PPy/N-PCM provide the possibility for its commercialization.

Hierarchical Nylon-6/reduced graphene oxide/polyaniline nanocomposites with enhanced dielectric properties for energy storage applications

Abstract Materials with high specific energy and specific power, along with chemical and structural stability, are in huge demand due to their numerous applications, including solid-state electronic devices and wearable electronics. Nanocomposites comprising of both conducting and non-conducting polymers exhibit excellent charge transfer mechanism along with high dielectric strength and structural stability, which enhances their appropriateness as efficient energy storage materials. Herein, we explore the application of Nylon-6 (PA6), polyaniline (PANI) and reduced graphene oxide (rGO) in preparing ternary nanocomposite (PA6/rGO/PANI) by varying the ratio of PA6 and PANI, for a fixed amount of rGO along with binary (PA6/PANI and rGO/PANI) nanocomposites. Among them, PA6/rGO/PANI 1:2 exhibits an excellent supercapacitance performance owing to its high surface area, low charge transfer resistance, high cyclic stability, and exceptional ionic rate capability. We have observed reasonable dielectric properties (viz., dielectric permittivity and dielectric loss), which is attributed to the stacking property of rGO with PA6 and PANI chains. The in-situ polymerization of PANI ensures the formation of well-dispersed nanocomposites with the hierarchical nanostructures, as revealed by the detailed morphological study. The galvanostatic charge-discharge measurement exhibits remarkable reversibility with capacitance retention of ~ 98%. The fabricated symmetric supercapacitor device based on PA6/rGO/PANI 1:2 exhibits noteworthy specific capacitance (38 F g−1), specific energy (~ 3.66 Wh kg‒1) and specific power (~ 234.84 W kg‒1), suggesting significant charge accumulation over the electrode surfaces, which is attributed to the synergistic effect of PA6 and PANI in the presence of rGO. The excellent electrochemical properties indicate its potential applications in self-powered electronic appliances effectively.

Ultrafine Tin Dioxide Nanoparticles Grown on Nitrogen-doped Graphene with Rich Pyrrolic Nitrogen for Excellent Supercapacitor Performance

Ultrafine Tin Dioxide Nanoparticles Grown on Nitrogen-doped Graphene with Rich Pyrrolic Nitrogen for Excellent Supercapacitor Performance

Nitrogen/Oxygen Enriched Hierarchical Porous Carbons Derived from Waste Peanut Shells Boosting Performance of Supercapacitors

AbstractThe high specific surface area and the fine electrical conductivity are the vital impacts, but they are always a pair of mutually counterbalancing factors in carbon‐based supercapacitors. Herein, a facile strategy of the combined CoCl2 catalytic graphitization and ZnCl2 activation is applied to synthesize porous carbonaceous materials with enriched nitrogen and oxygen doping from a cheap and abundant biowaste of peanut shells. The as‐produced carbon materials possess high surface area (1745–2257 m2 g−1), naturally nitrogen/oxygen co‐doping, and hierarchical porous structure. These physicochemical properties jointly endow these materials excellent supercapacitive performances: a high gravimetric specific capacitance of 343 F g−1 at 0.5 A g−1 and enduring long‐cycle performance of 90.9% capacitance retention after 10 000 cycles at 10 A g−1 in a 3‐electrode system with 6 m KOH electrolyte as well as a superior energy density of 42 Wh kg−1 at the high power density of 375 W kg−1 in an organic electrolyte. This low‐cost and facile approach shall open a new avenue to produce carbon materials with both high surface area and superior graphitization from the plentiful biomass for the potential energy storage applications.

Facile and low‐cost production of Lantana camara stalk‐derived porous carbon nanostructures with excellent supercapacitance and adsorption performance

Facile and <scp>low‐cost</scp> production of <scp> <i>Lantana camara</i> stalk‐derived </scp> porous carbon nanostructures with excellent supercapacitance and adsorption performance

Construction of Ta-Cu7S4 negative electrode for high-performance all-solid-state asymmetric supercapacitor

Constructing electronic structure of the electrode materials is an effective approach to enhance the electrochemical activity. The substitution of high-valence metal ions can optimize the electronic structure of host materials. And there are few reports using this way to enhance supercapacitor performances. Herein, the isomorphous replacement by tantalum in Cu7S4 (Ta-Cu7S4) materials were fabricated by hard-template method and designed as negative electrode materials for solid-state supercapacitor (SSC). The unique hollow structure increased the specific areas of active materials and enabled the effective contact between electrode and electrolyte. Density functional theory (DFT) calculations indicate that the replacement of Ta element optimized the electronic structure, endowing the Ta-Cu7S4 with good electrical conductivity and more active sites. Moreover, the Ta element acted as an ‘electron reservoir’, which decreased the adsorption energy of OH– on the surface of electrode material, carried the electron to trigger redox reaction on Cu active sites continuously. These factors resulted the obtained Ta-Cu7S4 exhibited the excellent supercapacitor performances. When used as a negative electrode material, the Ta-Cu7S4 had an outstanding specific capacitance (675F g−1 at 1 A g−1) and good rate capacity (363.1F g−1 at 10 A g−1). In addition, the assembled SSC showed high energy density (111.1 Wh kg−1 at power density of 800 W kg−1) and long-term cyclic stability of retaining 83.3% after 5000 charge/discharge cycles. This work reports a low-cost and efficient Cu7S4-based supercapacitor material by Ta incorporating, and infer this new strategy can be used in other energy storage application devices.

Template induced self-oxidative polymerization of phenols to mesoporous carbon doped with faradaic active oxygen for high-performance supercapacitor

Facile synthesis of nanocarbons with rich faradaic-active functionalities is urgently needed for supercapacitor in aqueous electrolytes to address the bottleneck of low energy density (usually below 10 Wh/kg). Herein, we report a template induced self-oxidative polymerization method for the fabrication of nanocarbon with commercial Mg(OH)2 as template to absorb phenol (catechol or phloroglucinol) via acid-base interaction. The absorbed phenol undergoes self-oxidative polymerization to form a composite of polyphenol and template. The resultant flower-like material with open access morphology display large surface area (1303 m2/g), rich mesoporosity (over 80%), and rich faradaic oxygen functionalities (7.4 atom%) in the forms of -C=O and -C–O- groups. Benefiting from these features, the phloroglucinol derived product (PMC973) exhibits excellent supercapacitor performances in aqueous electrolyte including ultrahigh energy density of 36.7 Wh/kg (at 1000 W/kg), maintaining energy density of 22.9 Wh/kg at 18 800 W/kg, superior capacitance retention of over 70% and excellent cycling stability with 97.8% capacity retention after 10 000 charge/discharge cycles, offering huge potential for energy storage. The developed strategy avoids the use of harmful formaldehyde as linker reagent, thus providing a green and simple approach for the fabrication of functional nanocarbons that are applicable in a large numbers of fields.

Constructing Fe3O4/Nitrogen-doped Graphene Composites with Rich Pyrrolic Nitrogen for Excellent Supercapacitor Performance

Constructing Fe3O4/Nitrogen-doped Graphene Composites with Rich Pyrrolic Nitrogen for Excellent Supercapacitor Performance