High-performance Supercapacitor Electrode Research Articles

Acid-modified biomass-based N-doped O-rich hierarchical porous carbon as a high-performance electrode for supercapacitors.

In contemporary society, the conversion and efficient utilization of waste biomass and its derivatives are of great significance. Carbonized wood (CW) is an easily accessible and cost-effective green resource, but it has limitations as an electrode material due to its low specific surface area, limited active sites and poor conductivity. Therefore, it is crucial to improve the performance of biomass-based materials by using activation, heteroatom doping and modification methods to enhance the specific surface area and active sites. In this study, we developed acid-modified urea-doped activated carbonized wood (AUACW) with a three-dimensional (3D) porous structure and porosity, achieving a high specific surface area of 1321.3 m2 g-1. In addition, the degree of graphitization (ID/IG = 1.0) provides good conductivity and a large number of active sites, which are conducive to charge transfer and ion diffusion. The increase of nitrogen and oxygen elements enhances the surface wettability of the material and provides additional pseudocapacitance. The specific capacitance of AUACW reaches 435.84 F g-1 at 0.8 A g-1 with a 93.6% capacitance retention after 10 000 cycles in a 1 M KOH electrolyte. More attractively, a symmetrical supercapacitor (SSC) based on AUACW delivers an energy density of 22.61 W h kg-1 at a power density of 533.26 W kg-1. This work demonstrates the promising potential of utilizing waste biomass to develop green and valuable carbon materials for supercapacitors.

High-Performance Supercapacitor Electrodes from Fully Biomass-Based Polybenzoxazine Aerogels with Porous Carbon Structure

In recent years, polybenzoxazine aerogels have emerged as promising materials for various applications. However, their full potential has been hindered by the prevalent use of hazardous solvents during the preparation process, which poses significant environmental and safety concerns. In light of this, there is a pressing need to explore alternative methods that can mitigate these issues and propel the practical utilization of polybenzoxazine aerogels. To address this challenge, a novel approach involving the synthesis of heteroatom self-doped mesoporous carbon from polybenzoxazine has been devised. This process utilizes eugenol, stearyl amine, and formaldehyde to create the polybenzoxazine precursor, which is subsequently treated with ethanol as a safer solvent. Notably, the incorporation of boric acid in this method serves a dual purpose: it not only facilitates microstructural regulation but also reinforces the backbone strength of the material through the formation of intermolecular bridged structures between polybenzoxazine chains. Moreover, this approach allows ambient pressure drying, further enhancing its practicability and environmental friendliness. The resultant carbon materials, designated as ESC-N and ESC-G, exhibit distinct characteristics. ESC-N, derived from calcination, possesses a surface area of 289 m2 g−1, while ESC-G, derived from the aerogel, boasts a significantly higher surface area of 673 m2 g−1. Furthermore, ESC-G features a pore size distribution ranging from 5 to 25 nm, rendering it well suited for electrochemical applications such as supercapacitors. In terms of electrochemical performance, ESC-G demonstrates exceptional potential. With a specific capacitance of 151 F g−1 at a current density of 0.5 A g−1, it exhibits superior energy storage capabilities compared with ESC-N. Additionally, ESC-G displayed a more pronounced rectangular shape in its cyclic voltammogram at a low voltage scanning rate of 20 mV s−1, indicative of enhanced electrochemical reversibility. The impedance spectra of both carbon types corroborated these findings, further validating the superior performance of ESC-G. Furthermore, ESC-G exhibits excellent cycling stability, retaining its electrochemical properties even after 5000 continuous charge–discharge cycles. This robustness underscores its suitability for long-term applications in supercapacitors, reaffirming the viability of heteroatom-doped polybenzoxazine aerogels as a sustainable alternative to traditional carbon materials.

Nitrogen-Doped Porous Carbons Derived from Peanut Shells as Efficient Electrodes for High-Performance Supercapacitors

Nitrogen-Doped Porous Carbons Derived from Peanut Shells as Efficient Electrodes for High-Performance Supercapacitors

Utilizing rubber plant leaf petioles derived activated carbon for high-performance supercapacitor electrodes

This research introduces a novel and sustainable method that exploits the untapped potential of waste biomass, specifically converting dead leaf petioles from Ficus elastica, an industrial crop commonly known as rubber plants, into high-performance activated carbon (AC) for supercapacitor electrodes through a straightforward pyrolysis process. The prepared AC is used as an electrode substance to construct symmetrical supercapacitors. It underwent detailed morphological and structural analyses through various analytical instruments to assess the AC's performance and quality. Electrochemical assessments using a two-electrode configuration with 1 M KOH as the electrolyte revealed that the AC electrodes display exemplary characteristics of electric double-layer capacitance. This conclusion was drawn from observing cyclic voltammetry curves that were rectangular and symmetrical across scan rates ranging from 10 to 100 mV/s. Remarkably, at a scan rate of 10 mV/s, these AC electrodes achieved a specific capacitance of 128 F/g. The superior performance of the AC, when compared to other biomass-derived electrode materials, can be attributed to its extensive surface area and significant porosity. Moreover, electrodes crafted from AC derived from rubber plants showed remarkable durability over 10000 charge-discharge cycles, maintaining 89 % of their original capacitance and achieving a Coulombic efficiency of up to 87 %. During prolonged discharge periods, these electrodes exhibited a high specific capacitance, which contributed to achieving a power density of 200 W/kg and an energy density of 11.4 Wh/kg. This study highlights the viability of rubber plant waste in advanced energy storage systems and significantly contributes to sustainable material science. By offering an eco-friendly approach for supercapacitor electrode fabrication, this research aligns with global efforts towards sustainable energy storage technologies, demonstrating the practicality of environmentally benign materials in high-performance applications.

High-performance battery type bismuth vanadate electrodes for supercapacitors

High-performance battery type bismuth vanadate electrodes for supercapacitors

Hierarchically structured Cu2P2O7 nanoflakes as a binder-free electrodes for high-performance supercapacitors

Metal phosphates-derived materials are emerging as promising candidates for electrode materials in energy storage systems due to their excellent redox properties and high electrical conductivity. In this work, we present a novel study and first report on the fabrication of binder-free electrodes using ultrathin Cu2P2O7 nanoflakes, facilitated through a cost-effective and industrially scalable chemical bath deposition (CBD) technique. These electrodes exhibit a unique surface architecture resembling micro-spherical flower structures, which are directly grown on flexible and conductive nickel foam (NF) substrates. The nanoscale structure of the Cu2P2O7 electrodes is meticulously designed to provide high porosity and an impressive specific surface area, allowing for efficient electrolyte ion infiltration. Consequently, these electrodes exhibit an exceptional specific/areal capacitance value of 1187 F g−1, 1894 mF cm−2 at a scan rate of 5 mA cm−2 and a specific capacity value of 644 C g−1. Notably, when integrated into an aqueous asymmetric supercapacitor (AASC) device, the Cu2P2O7-derived micro-sized flower structure delivers a significant energy density of 39.46 Wh kg−1, a notable specific power of 1.08 kW kg−1, and maintains an exceptional 99 % retention even after 10,000 charge/discharge cycles. This research highlights the potential of transition metal phosphates (TMPOs), specifically Cu2P2O7, as superior electrode materials for supercapacitor applications, offering a scalable and cost-effective approach for enhancing energy storage performance.

Structural and Electrochemical Evolution of Water Hyacinth-Derived Activated Carbon with Gamma Pretreatment for Supercapacitor Applications.

This study introduces a gamma pretreatment of water hyacinth powder for activated carbon (AC) production with improved electrochemical properties for supercapacitor applications. The structural and morphological changes of post-irradiation were meticulously analyzed using scanning electron microscopy (SEM), Raman spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) analysis, and X-ray photoelectron spectroscopy (XPS). The pretreatment significantly modifies the pore structure and reduces the particle size of the resulting activated carbon (WHAC). Nitrogen adsorption-desorption isotherms indicated a substantial increase in micropore volume with escalating doses of gamma irradiation. Electrochemically, the activated carbon produced from pretreated WH at 100 kGy exhibited a marked increase in specific capacitance, reaching 257.82 F g-1, a notable improvement over the 95.35 F g-1 of its untreated counterpart, while maintaining 99.40% capacitance after 7000 cycles. These findings suggest that gamma-pretreated biomasses are promising precursors for fabricating high-performance supercapacitor electrodes, offering a viable and environmentally friendly alternative for energy storage technology development.

Synergistic Interaction of Siloxene and Polyaniline Nanocomposite for High-Performance Supercapacitor Electrodes

Synergistic Interaction of Siloxene and Polyaniline Nanocomposite for High-Performance Supercapacitor Electrodes

High-performance supercapacitor electrode materials from composite of bamboo tar pitch activated carbon and tannic acid carbon quantum dots

A novel composite electrode material comprising bamboo tar pitch-based activated carbon (BTPAC) and tannic acid-derived carbon quantum dots (TACDs) was prepared. The integration of TACDs into the composite BTPAC-60/TACD not only preserved the high conductivity characteristic of BTPAC but also enhanced its hydrophilicity, pore structure, and specific surface area. Electrochemical evaluations revealed that BTPAC-60/TACD delivers a specific capacitance of 677.7 F/g at 0.5 A/g in a three-electrode system, and 281.8 F/g at 1 A/g in a two-electrode setup. Impressively, it achieves an energy density of 56.4 Wh/kg at a power density of 600 W/kg and maintains 95.7 % of its capacitance after 10,000 cycles. This research not only capitalizes on the high-value application of bamboo tar pitch but also provides a new perspective for the development of high-performance supercapacitor electrodes.

Bimetallic MOF derived Ni[sbnd]Mn phosphide for high-performance supercapacitor electrode material

Nickel‑manganese bimetallic phosphides are prepared by phosphidization of MOF-derived bimetallic hydroxides. The bimetallic phosphides exhibit crystalline Ni2P phase, show high specific surface area, and are composed of nanosheets. When supported on carbon cloth (CC) and used as the electrode material in 4 M KOH, the (Ni0.93Mn0.07)2P-18/CC shows a specific capacitance of 851.1C g−1 at 1 A g−1 and maintains 84.87 % capacity after 5000 cycles. The origin of the high specific capacity is investigated, and electron interaction between Mn and Ni sites, the high specific surface area, and the facile ion transport leads to the high specific capacity and stability. The constructed (Ni0.93Mn0.07)2P-18//AC asymmetric supercapacitor has an energy density of 59.83 Wh kg−1 at a power density of 750 W kg−1 and a capacity retention of 95.5 % after 5000 cycles.

Non-preoxidation synthesis of MXene integrated flexible carbon film for supercapacitors

Although the flexible carbon film integrated with MXene has been proven to be a new generation of supercapacitor material with good energy storage prospects, the MXene oxidation and the lack of active sites during the preparation of the carbon film can lead to irreversible capacity loss. Herein, a flexible carbon film constructed by MXene-integrated N-doped cavity-interconnected porous carbon nanofibers was prepared by a non-pre-oxidation synthesis strategy combining electrospinning and metal–organic framework derivatization. This flexible carbon film overcomes the oxidation problem of MXene during the stabilization of polyacrylonitrile, and the derived porous structure of cavity interconnection exposes more active sites. Due to its unique structural characteristics and ideal chemical composition, this independent flexible carbon film exhibits significantly enhanced electrochemical performance as an electrode material for supercapacitors. It exhibits an energy density of 26.2 Wh kg−1 at a power density of 500 W kg−1, and a capacitance retention rate of 96.3 % after 10,000 charge–discharge cycles. This study provides a unique strategy for the preparation of high-performance flexible carbon films, and this technology can also be extended to other integrated CNF composites for the design of high-performance supercapacitor electrodes.

Heterostructure Ni3P/CoP2/NiCo2O4/CC nanowire material as a trifunctional electrode for high-performance supercapacitors and electrocatalysis

The design and preparation of efficient and cost-effective multifunctional active materials for energy storage and conversion are essential component in achieving the current clean energy development. Herein, we have successfully synthesized heterostructure Ni3P/CoP2/NiCo2O4/CC nanowires with vertical array structure on carbon cloth by a simple strategy of solvothermal-annealing and phosphate treatment. The abundant heterogeneous interfaces and synergistic effect between the transition metal oxides/phosphides endow the material with excellent multifunctional properties. As a supercapacitor electrode, the Ni3P/CoP2/NiCo2O4/CC electrode possesses an exceptional specific capacitance of 2349 F g−1 at 1 A g−1. At a power density of 900 W kg−1, the built asymmetric supercapacitor achieves a high energy density of 37.5 Wh kg−1. Furthermore, an initial capacitance retention rate of 85 % was still maintained after 25,000 cycles. When used as electrocatalyst, the required oxygen evolution reaction and hydrogen evolution reaction overpotentials for a current density of 10 mA cm−2 are only 267 mV and 98 mV, respectively. Meanwhile, it presents superior overall water splitting activity (1.64 V@10 mA cm−2) and catalytic stability. This study affords additional perspectives for the reasonable design of non-noble metal based multifunctional materials to meet the diversified energy development.

NiCoMn-LDH with core-shell heterostructures based on CoS nanotube arrays containing multiple ion diffusion channels for boosted supercapacitor applications

Nanostructure engineering and composition rationalization are crucial for materials to become candidates for high-performance supercapacitor. Herein, a novel core-shell heterostructured electrode, combining CoS hollow nanorods with NiCoMn-layered double hydroxides (LDH) ternary metal nanosheets, were prepared on carbon cloth by reasonably controlled vulcanization and electrodeposition. By optimizing electrodeposition conditions, the material's structure and properties can be fine-tuned. The enhanced capacitance of the optimized carbon cloth (CC)@CoS/NiCoMn-LDH-300 electrode (4256.0 F g−1) lies in the open space provided by CoS and the establishment of a new charge transfer channel across the interfaces of CC@CoS/NiCoMn-LDH-300 nanosheets. This is further demonstrated by Density functional theory (DFT) simulations based on OH− adsorption energy, which produces faster redox charge kinetics and significantly enhances the electrode's energy storage capacity. The hybrid supercapacitor, integrating the optimized CC@CoS/NiCoMn-LDH-300 electrode with active carbon, demonstrates the highest energy density of 86 Wh kg−1 (under the power density of 850 W kg−1) and the long cycle stability of 89.7%. This study aims to go beyond simple binary LDH by constructing a ternary LDH with a hierarchical core-shell heterostructure to provide an effective and feasible new concept for high-performance supercapacitor electrode materials via rational structure design.

Graphitic carbon nitride film deposited with nitrogen-doped carbon nanoparticles as electrode for high-performance supercapacitors

Graphitic carbon nitride film deposited with nitrogen-doped carbon nanoparticles as electrode for high-performance supercapacitors

Ti3C2Tx MXene/reduced graphene oxide/cellulose nanocrystal-coated cotton fabric electrodes for supercapacitor applications

Textile-based electrodes are the most important components of wearable and portable supercapacitors. Ti3C2Tx MXene and reduced graphene oxide (rGO) have a great potential for the fabrication of high-performance textile supercapacitor electrodes. In this work, rGO was synthesized with the presence of cellulose nanocrystal (CNC) and Ti3C2Tx/rGO/CNC dispersions with different rGO/CNC contents were prepared. The plain-woven cotton fabrics were coated by homogenous Ti3C2Tx and Ti3C2Tx/rGO/CNC dispersions (5% wt., 15% wt., 30% wt. and 50% wt. rGO/CNC content) and characterized by X-ray Diffraction, Fourier Transform Infrared spectroscopy and Scanning Electron Microscopy techniques. The electrochemical characterization techniques showed that Ti3C2Tx/rGO/CNC loaded fabric electrodes up to 15 wt.% rGO/CNC content exhibited a high specific capacitance of 501.1 F g−1 at a current density of 0.3 A g−1 with low internal electrode resistance, and a good electrochemical stability. The results also showed that MXene/rGO/CNC based high-performance textile supercapacitor electrodes can be prepared by simple drop-casting method.Graphical

Oxidative MnO2 Template Assisted Electrochemical Fabrication of Graphene/Polypyrrole Supercapacitor Electrodes.

Improving the morphological structure of active materials is a reliable strategy for the fabrication of high-performance supercapacitor electrodes. In this study, we introduce a feasible approach to constructing the graphene/polypyrrole (PPy) composite film implanted onto the current collector through a two-step electrochemical deposition method utilizing MnO2 as an intermediary template. The reduced graphene oxide (rGO) hydrogel film is first hydrothermally grown on a carbon cloth (CC) substrate to obtain a porous rGO@CC electrode on which MnO2 is electrodeposited. Then the as-prepared rGO/MnO2@CC electrode is subjected to the electrochemical polymerization of pyrrole, with MnO2 acting as an oxidizing template to facilitate the oxidative polymerization of pyrrole, ultimately yielding an rGO/PPy composite film on CC. The PPy synthesized via this methodology exhibits a distinctive interconnected structure, resulting in superior electrochemical performance compared with the electrode with PPy directly electrodeposited on rGO@CC. The optimized electrode achieves an impressive specific capacitance of 583.6 F g-1 at 1 A g-1 and retains 83% of its capacitance at 20 A g-1, with a capacitance loss of only 9.5% after 5000 charge-discharge cycles. The corresponding all-solid-state supercapacitor could provide a high energy density of 22.5 Wh kg-1 and a power density of 4.6 kW kg-1, with a capacitance retention of 82.7% after 5000 charge-discharge cycles. Furthermore, the device also demonstrates good flexibility performance upon bending at 90 and 180°. This work presents an innovative method for the preparation of carbon material/conducting polymer electrodes with specific structural characteristics and superior performance.

A sustainable solution: Conversion of distillers' grains waste into high-performance supercapacitor electrode materials for energy storage applications

The development of cost-effective biomass-derived carbon with good electrochemical properties is crucial for advancing energy storage devices sustainably. One feasible approach to producing supercapacitor electrode materials is the conversion of heteroatom-rich biomass waste into heteroatom self-doped hierarchical porous carbons with favorable electrochemical properties. In this study, distillers' grains with abundant crude fiber and protein were utilized as precursors to prepare N, S self-doped hierarchical porous carbon, which presents a high specific surface area of 3642.87 m2 g−1. The N, S doping could improve the interfacial wettability of electrode materials and enhance the pseudocapacitive effect of the materials. In three-electrode system, the carbon delivered a high capacitance of 347 F g−1 at 1 A g−1. Symmetrical capacitors assembled with PVA/KOH gel electrolytes delivered an ultrahigh energy density of 11.29 Wh kg−1 at a power density of 250 W kg−1. This strategy provides a practical, low-cost, and renewable design approach of carbon electrode for high-performance supercapacitors.

Palladium enhanced electrochemical supercapacitive performance of chromium oxide thin films synthesized by sputtering process

Recently, the use of transition metal oxide electrodes for supercapacitor applications has increased due to the possibility of variable mixed valence states. The present study has established the use of Pd-Cr2O3 composite thin films as a working electrode for high-performance supercapacitors. The reactive dc magnetron co-sputtering method has been used for the fabrication of thin film of Cr2O3 and Pd-Cr2O3 on SS-304 substrate. X-ray diffraction and X-ray photoemission spectroscopy techniques were used to examine the surface chemistry and phase purity of chromium oxide and Pd-Cr2O3 composite thin films. The incorporation of Pd in Cr2O3 delivers a drastic change in the surface morphology. Due to the modified morphology and electronic properties, a noticeable improvement in the electrochemical properties of Pd-Cr2O3 electrode is observed. The obtained value of specific capacitance for this electrode is 401 Fg−1 at 0.1 mAcm−2 scan rate and within the potential window range 0 to +1.2 V. This value of specific capacitance is almost twice in comparison to the Cr2O3 based electrode. The Pd-Cr2O3 composite thin film shows a good cycle retention capability of 8000 cycles with 87.5 % retention. The obtained value of energy density and power density for Pd-Cr2O3 electrode was 80.2 Whkg−1 and 3.23 kWkg−1, respectively at 0.1 mAcm−2. Consequently, this composite material electrode can be seen as a promising advancement for electrodes in supercapacitor devices.

Nanostructured binary transition-metal-sulfides and nanocomposites as high-performance electrodes for hybrid supercapacitors

Supercapacitors (SCs) are attractive as promising energy storage devices because of their distinctive attributes, such as high power density, good current charge/discharge ability, excellent cyclic stability, reasonable safety, and low cost. Electrode materials play key roles in achieving excellent performance of these SCs. Among them, binary transition metal sulfides (BTMSs) have received significant attention, attributed to their high conductivity, abundant active sites, and excellent electrochemical properties. This topic review aims to summarize recent advances in principles, design, and evaluation of the electrochemical performance for nanostructured BTMSs (including nickel–cobalt sulfides, zinc–cobalt sulfides, and copper–cobalt sulfides.) and their nanocomposites (including those carbon nanomaterials, transition metal oxides, binary transition metal oxides, transition metal sulfides, and polymers). Nanostructuring of these BTMSs and nanocomposites as well as their effects on the performance were discussed, including nanoparticles, nanospheres, nanosheets, nanowires, nanorods, nanotubes, nanoarrays, and hierarchitectured nanostructures. Their electrochemical performance has further been reviewed including specific capacitance, conductivity, rate capability, and cycling stability. In addition, the performance of hybrid supercapacitors (HSCs) assembled using the nanostructured BTMSs as the cathodes also have been summarized and compared. Finally, challenges and further prospects in the HSCs-based BTMS electrodes are presented.

Highly conductive titanium nitride core sterically reinforced nickel-vanadium layered double hydroxides for supercapacitors

Nickel vanadium layered double hydroxide (NiV-LDH) is a highly promising electrode material for supercapacitors, but its poor electrochemical durability and conductivity limit its capacitance performance as a high-performance supercapacitor electrode. In contrast, titanium nitride (TiN) stands out for its outstanding electrochemical durability and superior conductivity. In this work, a composite material (TiN@NiV-LDH) with outstanding electrochemical performance was prepared by a simple hydrothermal method, where nickel vanadium layered double hydroxide nanosheets were vertically grown in a staggered manner on the surface of amorphous titanium nitride nanoparticles. The results demonstrate that at a current density of 2 A g−1, the capacitance of TiN@NiV-LDH reaches 712.4 F g−1. In addition, the assembled TiN@NiV-LDH//AC asymmetric supercapacitor exhibits a high energy density of 136.5 Wh kg−1 at a high power density of 1549.9 W kg−1, and after 10,000 cycles at a high current density of 20 A g−1, it retains 80.2 % excellent cyclic stability. This work, based on nickel vanadium layered double hydroxide and utilizing titanium nitride modification, aims to enhance the long-term stability of nickel vanadium layered double hydroxide while preserving its advantageous properties, providing a promising strategy for designing efficient supercapacitor electrodes.