Electrochemical Supercapacitors Research Articles

Ethylenediamine-functionalized metal-organic frameworks for applications of electrochemical supercapacitors as an additive

In this study, the impact of incorporating ethylenediamine (ED)-functionalized metal-organic frameworks (MOFs) on enhancing the electrochemical performance of polypyrrole(PPy)-based conducting polymers as supercapacitor electrode materials was investigated. The stability of terephthalic acid-containing MOFs in different environments, including exposure to acids, relies on the specific metal ions and ligands utilized in their construction. In this research, ED treatment was chosen for its resistance to acid attack. Unlike the post-synthetic modifications observed in previous literature regarding ED-modified MOF5, this study introduces a unique approach where ED is directly integrated into the framework in a single step. The resulting materials, referred to as ED-MOF, were employed in creating a novel composite material concurrently with polypyrrole, designed for use as electrode materials in supercapacitor applications. The optimal loading in the electrochemical preparation of polypyrrole-based conducting polymers was determined using cyclic voltammetry and electrochemical impedance spectroscopy techniques. Areal capacitance for the resulting electrodes was evaluated through cyclic charge-discharge experiments. The areal capacitance of the ED-ZnMOF/1@/PPy/PGE electrode was found to be 575.2 mF.cm−2 at a charge/discharge current density of 1 mA.cm−2. This research underscores the potential advantages of combining conducting polymers and metal-organic frameworks in supercapacitors, as well as other electrochemical systems.

Screen-Printed Stretchable Supercapacitors Based on Tin Sulfide-Decorated Face-Mask-Derived Activated Carbon Electrodes with High Areal Energy Density

Screen-Printed Stretchable Supercapacitors Based on Tin Sulfide-Decorated Face-Mask-Derived Activated Carbon Electrodes with High Areal Energy Density

Engineering Local Graphitic Domains to Balance Defect Active Site and Electronic Conduction Ability in Coal‐Derived Carbon Anode for Superior Potassium Ions Storage

AbstractPotassium‐ion hybrid capacitors (PIHCs) are regarded as one of the promising candidates for large‐scale energy storage technologies. Nevertheless, the lack of suitable anode materials combined with fast ion diffusion kinetics and favorable cycle stability restricts their application. Herein, a catalyst‐confined graphitization strategy is proposed to synthesize low‐cost coal‐based carbon anodes, which have controllable heteroatom co‐doping and rich defect sites, together with local graphitic domains. Density functional theory calculations and kinetic analysis are performed to uncover the coupling effect for heteroatom dual‐doping and defective structures. Importantly, the introduction of graphitic domains ensures good electric conductivity and charge transfer kinetics while preserving rich defects and active sites. The optimized NC‐950 exhibits superior potassium storage capacity, which delivers a high reversible specific capacity (363.3 mAh g−1), impressive rate capability (93.9 mAh g−1 at 2 A g−1), and stable cycling performance. As a practical device application, the PIHCs (NC‐950//AC) are assembled using the NC‐950 anode and commercial activated carbon (AC) cathode, which exhibits the maximum energy density of 97.0 Wh kg−1 and excellent cycling stability (10 000 cycles). Significantly, this work unveils a new pathway to developing low‐cost and fast reaction kinetics carbon anode for advanced electrochemical supercapacitors.

Nanostructural engineered titanium dioxide by rare earth metals dual doping for electrochemical supercapacitor applications

Nanostructural engineered titanium dioxide by rare earth metals dual doping for electrochemical supercapacitor applications

A battery-type cathode with RuO2 modified Ni11(HPO3)8(OH)6 for asymmetric supercapacitors

Phosphates are a kind of promising electrode materials because they can provide numerous cavities and several reaction sites to be favored for storing anions and cations. However, the widespread application of phosphates are limited by their intrinsically low electronic conductivity. RuO2/hydrated RuO2 exhibits high conductivity and excellent electrochemical properties. Reducing its dosage and increasing its specific surface area are the research concerns. Combining less RuO2 to Nickel phosphate (NiP) is expected to improve the electrochemical performance. RuO2-modified NiP (NiP-RuO2) electrode material is synthesized by a one-step hydrothermal reaction and its structural morphology and capacitive properties are investigated. The results indicate that NiP-RuO2 electrode consists of hydrated RuO2 and Ni11(HPO3)8(OH)6, and exhibits excellent battery-type electrochemical supercapacitor performance with a specific capacity of 878.06 C/g at 1 A/g. According to density functional theory (DFT) analysis, Ru-doped Ni11(HPO3)8(OH)6 has a narrower forbidden band width and higher conductivity than Ni11(HPO3)8(OH)6. Furthermore, the asymmetric supercapacitor (ASC) assembled by NiP-RuO2/NF and activated carbon (AC) electrode achieves a high energy density (43.58 Wh/kg) at a power density of 923.47 W/kg. When two ASC devices are connected in series, ten light-emitting diodes (LEDs) can be illuminated for ten minutes.

Synthesis and Electrochemical Performance of Flexible and Freestanding Graphene-Encapsulated PANi@MnO2/ECNFs Nanoscale Architectures for Electrochemical Supercapacitors

Synthesis and Electrochemical Performance of Flexible and Freestanding Graphene-Encapsulated PANi@MnO2/ECNFs Nanoscale Architectures for Electrochemical Supercapacitors

Electrochemical Supercapacitor Application of Electrochemically Produced Chlorine-Doped Graphene Oxide with Cobalt Sulfide-Based Compounds Produced from Recycling of Spent Li-Ion Batteries

Recycling of LiCoO2 (LCO) based Li-ion batteries for energy storage systems is crucial both environmentally and economically. Reusing active species of LCO cathodes minimizes waste and conserves resources, promoting sustainability in energy storage. We have investigated repurposing cobalt from spent LiCoO2 (LCO) type Li-ion batteries into a cobalt sulfide-based compound (CS), which was then employed as an electrode material in asymmetric supercapacitors. Initially, the LCO cathode compound underwent leaching, resulting in the precipitation of CS utilizing the sulfur source derived from cobalt ions present in the solution. Furthermore, chlorine-doped graphene oxide (Cl-GO) was synthesized via the chronoamperometric method utilizing a 5 M perchloric acid solution. Produced CS and Cl-GO were characterized by using spectroscopic and microscopic techniques. The resulting CS and Cl-GO powders were combined to form the composite positive electrode of coin cell type asymmetric supercapacitors (CCTAS), with graphite powder (GP) utilized in the preparation of the negative electrode. CCTAS were also characterized by using electrochemical techniques such as cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge. The highest areal capacitance, recorded as 101 mF.cm−2 at a scan rate of 10 mV.s−1, was achieved in the CS/Cl-GO%15//GP CCTAS, with a capacitance retention of approximately 94% observed after 1000 cycles.

Simple and affordable synthesis of a binder-free nickel-zinc sulfide electrode for high-performance supercapacitors

Due to the increasing demand for renewable energy solutions, aqueous energy systems have emerged as promising and sustainable technologies. Nanostructured transition metal sulfides, renowned for their exceptional properties, are prime candidates for electrochemical supercapacitors. In this study, we present the synthesis of nickel-zinc sulfide (Ni-Zn-S) as a binder-free supercapacitor material using the affordable successive ionic layer adsorption and reaction simple technique. The active nanomaterial was directly deposited onto a 3D Ni foam current collector substrate, negating the need for a binder. The synergistic combination of Ni and Zn enhances the electrode capacitance. Various electrochemical techniques were used to evaluate the loaded active material as a binder-free supercapacitor electrode in a 6 M KOH electrolyte. Results indicate pseudocapacitive performance, achieving a high specific capacitance of 400F/g at 0.7 A/g. This material retains 97 % of its capacity, even after 2000 cycles, showcasing exceptional long-term cycling stability. These findings underscore the potential of the Ni-Zn-S electrode for delivering low-cost, high-performance supercapacitors.

3D layered MgCo2O4@CoMoO4 porous nanomaterial arrays grown on nickel foams: Preparation and application as high-performance electrodes for supercapacitor

The advanced 3D layered porous MgCo2O4@CoMoO4 composite electrode (MCCo) was directly synthesized on a nickel foam substrate using a straightforward two-step hydrothermal approach. Among the various MCCo electrodes, the MCCo-7 h electrode demonstrated superior performance with a specific capacity of 2403 F g−1 due to its exceptional charge transfer internal resistance (Rs) and remarkable electrochemical characteristics. Notably, this performance surpassed that of MgCo2O4 (807 F g−1), MCCo-3 h (1224 F g−1), MCCo-5 h (1414 F g−1), MCCo-9 h (1936 F g−1), and CoMoO4-7 h electrode materials (442 F g−1). Furthermore, when MCCo-7 h was paired with activated carbon (AC) to construct a MCCo-7 h//AC device, it achieved an impressive energy density of 39 Wh kg−1 at a power density of 375 W kg−1, maintaining an impressive capacity retention of 83% even after 2000 cycles at a high current density of 5 A g−1. This groundbreaking work offers valuable insights and strategies for electrochemical energy storage and supercapacitors.

Mathematical expressions for simulation of supercapacitor voltammetry curves and capacitance dependence on scan rate

A straightforward RC series circuit model was proposed to fit the cyclic voltammetry experimental data of various symmetrical electrochemical supercapacitors. The model simulated the experimental behavior for exponential dependence of capacitance on the scan rate. In this model, the zero-scan rate capacitance was considered as a constant, and the equivalent serial resistance depended on the scan rate. Neither the equivalent parallel resistance nor a possible intrinsic dependence of capacitance on applied voltage was considered in the modelling.

Avocado seed biomass-assisted synthesis of heterostructure bismuth vanadate nanomaterial by combustion method for the application of electrochemical lithium battery storage and supercapacitor

With the global demand for lithium-ion batteries (LIBs), research is focused on developing advanced energy storage materials with high energy and power densities. Hetero-structured nanomaterials have garnered significant interest in energy storage applications based on their unique architecture providing sites for improved electrochemical activity. This work reports a facile single-step combustion synthesis of bismuth vanadate nanoparticles (BVNPs) using avocado seed powder, an economical and eco-friendly fuel source. By optimizing the precursor-to-fuel ratio to 1:1, highly pure phase BVNPs were obtained as characterized via XRD, FT-IR, SEM-EDAX, TEM, UV-DRS, PL, BET, and DLS analyses. When assessed as an electrode material for LIBs, the BVNP1:1 delivered an exceptional initial discharge capacity of 2166 mAhg−1 and a retention of ∼53 mAhg−1 over 90 cycles with 99% Coulombic efficiency. The BVNP1:1 electrode exhibited a maximum specific capacitance of 545.65 mF/cm2 at 2 mA/cm2 current density as a supercapacitor. The combination of scalable green synthesis, excellent phase purity, and superior electrochemical performance makes these BVNPs a promising and sustainable electrode material for forthcoming energy storage technologies to meet the surging energy needs.

Membrane based In-situ reduction of graphene oxide for electrochemical supercapacitor application

Reduced graphene oxide (rGO) is a widely studied electrode material for energy storage, however, its strong re-stacking tendency during chemical reduction always leads to a degraded specific surface area and thus limits its performance. Therefore, it is necessary to control the morphology of rGO during the reduction process. Here, we develop a novel in-situ membrane-based method for the reduction of graphene oxide (GO) using a green and efficient vitamin C (VC) aqueous solution as reductant. The obtained electrode material (vitamin C reduced GO via membrane-based method, VG-M) exhibits a specific capacitance of 174 F/g at 1 A/g and 75.9% of retention at 40 A/g, which is about 9 times better than the highly self-stacked material from conventional methods (vitamin C reduced GO via stirring method, VG-S). This designed method successfully achieves the maintenance of rGO sheet morphology through laminar confinement in GO membrane and presents a simple approach towards two-dimensional (2D) material morphology control.

Nitrogen-doped mesoporous carbon spheres decorated with NiCo alloy nanoparticles for high-performance electrochemical supercapacitors

Nitrogen-doped mesoporous carbon spheres (NMCSs) decorated with NiCo alloy nanoparticles (NiCo/NMCS) were prepared and examined for their prospective role as high-performance electrode materials. The average size and BET surface of the NMCSs are 488.1 nm and 660.9 m2g−1. The N content of the NMCSs and NiCo/NMCS-50 (NMCSs with 50 wt% of NiCo alloy nanoparticles (NPs)) was 1.49 wt% and 2.9 wt%, respectively. The NiCo alloy NPs, with an average diameter of 9.6 nm, were evenly incorporated into NMCSs. The NiCo/NMCS-50 exhibited a specific capacitance of 585 F g−1 when tested in a 6 M KOH solution at a current density of 1 A/g. The superior electrochemical performance of NiCo/NMCS-50 is attributed to the synergistic effect of mesoporous carbon structure and NiCo alloy NPs by improving redox-related mass transport and electron transfer. Symmetric supercapacitor devices assembled using two NiCo/NMCS-50 electrodes had a maximum energy density of 30.0 Wh kg−1 at a power density of 187.5 W kg−1 with notable cycling stability, maintaining 60.1 % of capacitance, up to 5,000 cycles. These results suggest that NiCo/NMCS composites have significant potential for utilization in high-energy storage applications.

Binder-Free Two-Dimensional Few-Layer Titanium Carbide MXene Ink for High-Performance Symmetric Supercapacitor Device Applications

A heightened interest in developing MXene (Ti3C2Tx) for energy storage is evident in binder-free MXene ink being directly applied to current collector Ni-foam. Moreover, 2D titanium carbide MXene, with a few layers of nanostructure, has been prepared for symmetric supercapacitor device applications. As-prepared MXene nanosheets exist in two forms: dried powder and ink, achieved through wet-chemical etching and dimethyl sulfoxide delamination from the MAX (Ti3AlC2) phase. This comparative study of electrode devices involves (i) MX-dry powder with binder/additive electrodes and (ii) binder-free MXene inks with directly applied MX-conductive inks. The surface morphological images of pure MX-powder/ink display few layers, and material analysis reveals the good crystalline nature of delaminated MXene (Ti3C2Tx) inks. The electrochemical symmetric supercapacitor device performances of pure MXene powder and binder-free directly applied/coated MXene (Ti3C2Tx) ink, in terms of cyclic voltammetry (CV) and impedance spectroscopy (EIS), exhibit galvanostatic charge–discharge (GCD) curves that show high specific capacitance (Csp) at 105.75 F/g at a current density of 1 A/g. A comparison of active material electrodes demonstrated excellent cycle stability. Hence, in this work, we confirmed the superior capacitive behavior of binder-free MXene ink (MX-I) compared to conductive additives with polymeric binders included in MXene electrodes.

Nitrogen-incorporated boron-doped diamond films for enhanced electrochemical supercapacitor performance

The electrochemical (EC) supercapacitor, known for its rapid charging, reliability, and versatile applications, demands optimized electrode characteristics and an understanding of their electrochemical behaviour. Although boron-doped diamond (BDD) holds promise as a supercapacitor electrode, a crucial gap exists in comprehending its material behaviour under specific growth conditions. Here, nitrogen-incorporated BDD (N-BDD) films with different microstructures are investigated. The morphology of N-BDD films is varied by tuning the substrate temperature (Ts) from 400 °C to 850 °C during the growth process. The diamond films grown at lower Ts = 400 °C consist of faceted grains, and the grain sizes shrink as Ts is increased (550 °C and 700 °C). Interestingly, the films grown at 850 °C (N-BDD850°C) show nanowire-like morphology with enhanced electrical conductivity. The spectroscopy and microscopy results reveal the concurrence of sp3-diamond and sp2-graphitic phases in the nanowire morphology. The EC supercapacitor studies disclose that formation of nanowire-like morphology for N-BDD850°C increases the active surface area and electron transport properties; hence, higher current response and enhanced specific capacitance (0.09 F cm−2 at a current density of 1.53 mA cm−2) are observed. Lifecycle stability of 82% is observed after 5000 cycles indicating the efficient performance of N-BDD850°C films.

Fabrication of hierarchically structured supercapacitor using N and S co‐doped activated carbons derived from Samanea saman biomass

AbstractBiomass‐derived activated carbons have emerged as highly promising electrode materials for electrochemical supercapacitors due to their remarkable characteristics, such as high surface area, cost‐effectiveness, and environmental sustainability. This study focuses on the synthesis of N and S co‐doped activated carbons (NSACs) from Samanea saman (rain tree) biomass through a combined hydrothermal‐chemical activation process. Leveraging the advantageous hierarchical structure inherent to biological sources, the resulting NSACs demonstrate enhanced ion transport, leading to remarkable capacity and power density. The NSACs synthesized by pyrolysis at 800°C exhibit exceptional specific capacitances of 434 and 401 Fg−1 in Na2SO4 and H2SO4 electrolytes, respectively, in a three‐electrode system. The capacitance retention of the same NSAC was found to be 77.6% at a corresponding current density of 10 Ag−1 in H2SO4 electrolyte. This outstanding electrochemical performance can be attributed to the material's high specific surface area (1402 m2 g−1), well‐defined hierarchical porous structure, and a substantial degree of graphitization. A symmetric supercapacitor constructed using the synthesized NSACs demonstrates notable energy densities of 14.5 and 25.0 Whkg−1, with H2SO4 and Na2SO4 electrolytes respectively. Furthermore, the symmetric supercapacitor exhibits excellent stability, retaining 91.3%–94.3% of its capacity after 5000 consecutive GCD cycles with H2SO4 and Na2SO4 electrolytes, respectively. The synergistic combination of the unique characteristics of NSACs derived from Samanea saman biomass presents a promising avenue for the development of high‐performance and environment‐friendly supercapacitors.

Hydrothermal synthesis of β-NiS layer structure nanoparticles for supercapacitor applications

At present, there is a significant research focus on development of sulfide based electrode materials for improving the performance of electrochemical supercapacitor (SC). Nickel sulfide (NiS) electrode materials has emerged attention as a promising candidate due to its high value of specific capacitance and outstanding redox activities. This study includes synthesis, characterization, and a novel electrode material called layer-like NiS that resembles a single-phase (β) is evaluated. At a current density of 3 mA g−1 in 3 M KOH electrolytes, the β-NiS electrode demonstrates an impressive specific capacitance of 780 F g−1 with 92 % cycling capacitance retention after 5000 cycles.

Solvent effects on the electrochemical performance of few layered MoS2 electrodes fabricated using FTO substrates

Owing to its exceptional structural, electrical, and optical features, Molybdenum disulphide (MoS2), a two-dimensional (2D) layered material with tuneable bandgap, finds its application in electrochemical supercapacitors for superior energy and power density. Because of their low toxicity and long-term energy storage, the development of MoS2-based supercapacitors is inevitable. The study of solvent effects on the electrochemical performance of a few layered MoS2 using FTO substrates is done for the first time to the best of our knowledge. Exfoliating bulk MoS2 powder in different solvents with variable surface tensions such as Ethanol, Ethylene Glycol (EG), Dimethylformamide (DMF), and Dimethyl Sulfoxide (DMSO) results in the formation of few-layered MoS2 structures. The sample’s structural, optical, and electrochemical behaviours are investigated using x-ray diffraction (XRD), atomic force microscopy (AFM), UV spectroscopy, Fourier transform infrared (FTIR), cyclic-voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS). XRD confirms the formation of a 2D MoS2 film with (002) planes and the optical investigation revealed the variation of layer-dependent bandgap with solvents. We observe both faradaic and non-faradaic charge storage mechanisms in the samples and demonstrate a superior pseudocapacitive behaviour for MoS2 in DMF with a maximum specific capacitance of 34.25 F g−1 at a current density of 1 A/g.

B-site disorder driven Griffiths-like phase and electrochemical behavior in Y2NiCrO6 double perovskite

In this investigation, nanoparticles of B-site disordered Y2NiCrO6 (YNCO) double perovskite were synthesized by the facile sol–gel method to evaluate their magnetic and electrochemical properties. Their crystallographic structure is monoclinic and the average size of the particles is 79±16 nm. XPS analysis indicated a mixed oxidation states of B-site transition metals Ni2+/Ni3+ and Cr2+/Cr3+. The mixed valence states of Ni and Cr, along with the mixed magnetic phases of YNCO, constitute a signature of the B-site disorder. This antisite disorder contributed to the observation of a Griffiths-like phase arising from ferromagnetic short-range interactions above the magnetic transition up to the Griffiths temperature, T G = 137 K. The synthesized YNCO double perovskite demonstrated a promising behavior as an electrode material for electrochemical supercapacitors. In a three-electrode system, it displayed a specific capacitance of 270 F g−1 at a current density of 0.5 A g−1. In a symmetric two-electrode system, YNCO exhibited a specific capacitance of 180 F g−1 at 0.5 A g−1, alongside an energy density of 6.25 Wh kg−1 at 250 W kg−1 power density. In both cases, we employed a mild 0.5 M neutral aqueous Na2SO4 solution as the electrolyte, in contrast to the typically employed corrosive and concentrated alkaline aqueous solution. The fascinating magnetic and charge storage properties of the B-site disordered YNCO double perovskite indicate its potential for use in spintronic devices and as efficient electrodes in symmetric hybrid supercapacitors.

Harnessing the potential of NiMn2O4 nanoparticle: a next-generation supercapacitor electrode material

This research addresses the pressing demand to enhance energy density and power in energy storage devices, including batteries, fuel cells, and supercapacitors. Here, NiMn2O4 is synthesized using the urea combustion method. Characterization techniques, including powder x-ray diffraction, field emission scanning electron microscopy, and BET analysis, are employed to investigate its properties. The diffraction peaks showed that NMO had a face-centered tetragonal structure, and the Scherrer equation was used to figure out the average crystallite size (t) as 8.73 nm. Its electrochemical behavior is extensively evaluated through cyclic voltammetry and galvanic charge–discharge measurements. The findings indicate that the fabricated NiMn2O4 electrodes exhibited remarkable specific capacitance and exceptional cycling stability, retaining 97% of their initial performance over 10000 cycles. The specific capacitance of the electrode from GCD was obtained 80 F g−1 at a current density of 0.25 A g–1. This study highlights the potential of NiMn2O4 as an electrode material for high-performance electrochemical supercapacitors, offering a viable solution for advancing energy storage technologies.