Electrode For Hybrid Supercapacitors Research Articles

Iodine Adsorption in Nanoporous Carbon to Fabricate Assimilated Battery Electrodes for Durable Hybrid Supercapacitors

A hybrid supercapacitor is designed by coupling a battery electrode with a capacitive electrode in a single device/cell to enhance energy density. In iodine-based hybrid supercapacitors, the nanoporous carbon serves as the electrode material; however, the cathode or positive electrode is charged with iodine via electrodeposition from a redox aqueous electrolyte, while a negative electrode stores charges at the electric double-layer. In this work, iodine is loaded via physical adsorption into the porosity of a carbon electrode, keeping the aqueous electrolyte free from iodide redox moieties. By this way, the risk of polyiodide (I3− and I5−) generation at the positive electrode leading to a shuttling-related performance loss of the hybrid supercapacitor is prevented. Chemical interactions of iodine with the carbon surface and within the pores have been investigated with Raman spectroscopy, thermogravimetry and electron microscopy. Electrochemical methods have been used to test individual electrodes and hybrid supercapacitors in aqueous NaNO3 and aqueous LiTFSI at 5 mol/L concentration for performance parameters such as energy efficiency, capacitance, self-discharge and cyclability. The hybrid supercapacitor in aqueous LiTFSI exhibits stable capacitance and energy efficiency during long-term aging tests at 1.5 V. Carbon nanoarchitecturing with iodine as shown in the present work offers an economical approach to enhance the performance of hybrid supercapacitors.

Zirconium doping facilitates a vertically aligned NiCoZr-layered hydroxide nanoneedle arrays electrode for hybrid supercapacitors exhibiting a 90,000 cycle durability

LDHs (Layered Double Hydroxides) are a kind of promising cathode material for high-performance hybrid supercapacitor. Nevertheless, it suffers quick capacitance decay after only thousands of cycles, which greatly prevents it from further application. In this contribution, zirconium (Zr) is introduced to the host layer of NiCo-LDH via a simple one-pot hydrothermal process. Owing to the strong bonding energy of ZrO (760 kJ mol−1) and special electronic structure (fully empty 4d orbits), the doped Zr could not only act as a structural stabilized element, but also change the mechanism of the energy storage process to alleviate the Jahn-Teller distortion of NiCo-LDH. Moreover, the introduction of Zr boosts an orderly growth of the LDHs, changing from disorder stack structure to vertically aligned nanoneedle arrays, which improve their structural stability. By controlling a varying level of Zr content, the electrode NiCoZr-LDH@CC with a Zr content ratio of 6.4 % delivers the best comprehensive electrochemical performance with a specific capacitance of 1758 F g−1 and good rate performance (73 % capacitance retention at 10 A g−1). The assembled asymmetric supercapacitor shows a highest energy density of 42.3 Wh kg−1 at 504 W kg−1 and an ultralong cycling lifespan beyond 90,000 cycles with a 97 % capacitance retention. The results exhibit the great potential of NiCoZr-LDH as a qualified candidate for high-performance hybrid supercapacitors.

Versailles Santa Barbara-5 derived bifunctional one-dimensional electrocatalysts of hierarchical Ni3S2 nanoprism@nanosheets arrays for self-supporting and binder-free efficient supercapacitor and methanol oxidation reaction

We herein present a structure consisting of two-dimensional (2D) single-crystal Ni3S2 nanosheets designed on one-dimensional (1D) Ni3S2 nanoprism arrays (also known as Ni3S2 nanoprism@nanosheets). These arrays are directly synthesized over nickel foam, which is referred to as Ni3S2/NF. These structures can be used as binderless, self-supporting electrodes for bifunctional methanol oxidation reaction (MOR) applications and high energy density hybrid supercapacitors (HSC). Ni3S2/NF is synthesized through the two steps of hydrothermal processes. In step I, 1D hexagonal Versailles Santa Barbara-5 (VSB-5) nanorod arrays have been prepared onto the surface of NF (denoted as VSB-5/NF). The precursor for step II was 1D VSB-5 nanorod arrays, which were transformed into Ni3S2 using Na2S as a sulfur source via the Kirkendall effect. Electrochemical examination results show that as-synthesized Ni3S2/NF electrode exhibited a high specific capacitance (Cs) of 145.0 mA h g−1 at 5 A g−1, low series resistance (0.18 Ω) and charge-transfer resistance (0.05 Ω), small relaxation time constant (τ0 = 8 ms) and high frequency response at 125.8 Hz. Ni3S2/NF has a superior specific capacity of 145.0 mA h g−1 at 5 A g−1 as a SC electrode. The Ni3S2/NF//CNTs/NF HSC can be operated up to 1.6 V in a 3 M KOH electrolyte, delivering an impressive energy density of 256.35 W h kg−1 at a power density of 6400 W kg−1. The as-assembled Ni3S2/NF//CNTs/NF HSC device exhibited an impressive stability of 81 % even after undergoing 10,000 charge-discharge cycles. When compared to previously reported catalysts, Ni3S2/NF was proved to be an excellent electrocatalyst for MOR due to its ability to generate a current density of 215.0 mA cm−2 at 0.5 VSCE, while maintaining a superior and stable current density of 619.2 mA cm−2 at 0.8 VSCE.

Convenient room-temperature synthesis of sulfur and nitrogen co-doped NiCo-LDH coupled with CNTs on NiCo foam as battery-type electrode for high performance hybrid supercapacitor

Convenient room-temperature synthesis of sulfur and nitrogen co-doped NiCo-LDH coupled with CNTs on NiCo foam as battery-type electrode for high performance hybrid supercapacitor

Ultrafast Microwave-Assisted Synthesis of Porous NiCo Layered Double Hydroxide Nanospheres for High-Performance Supercapacitors.

Currently, new clean energy storage technology must be effective, affordable, and ecologically friendly so as to meet the diverse and sustainable needs of the energy supply. In this work, NiCo-LDH containing intercalated EG was successfully prepared within 210 s using an ultrafast microwave radiation technique. Subsequently, a series of characterization and systematic electrochemical tests were conducted to analyze the composition, structure, and energy storage mechanism of the NiCo-LDH material. The Ni:Co ratio of 5:5 results in the highest capacitance value of 2156 F/g at 1 A/g and an outstanding rate performance of 86.8% capacity retention rate at 10 A/g. The results demonstrated that the unique porous structure of NiCo-LDH and large layer spacing were conducive to more electrochemical reactions. Additionally, an electrochemical test was carried out on the NiCo-LDH as a hybrid supercapacitor electrode material, with NiCo-LDH-5:5 serving as the positive electrode and activated carbon as the negative electrode, the asymmetric supercapacitor can achieve a maximum energy density of 82.5 Wh kg-1 and power density of 8000 W kg-1. The NiCo-LDH-5:5//AC hybrid supercapacitors own 81.5% cycle stability and 100% coulombic efficiency after 6000 cycles at 10 A/g.

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.

Enhanced cycling rate performance of three-dimensional NiO as a positive electrode for hybrid supercapacitor

Enhanced cycling rate performance of three-dimensional NiO as a positive electrode for hybrid supercapacitor

Polythiophene/nitrogen-doped reduced graphene oxide nanocomposite as a hybrid supercapacitor electrode

In this study polythiophene/nitrogen-doped reduced graphene oxide (Pth/n-rGO) was synthesized by in situ chemical polymerization. The correct synthesis of Pth/n-rGO nanocomposite was checked and confirmed through different spectral, elemental and morphological analysis. The supercapacitor performance of the Pth/n-rGO was higher than those of pure Pth and n-rGO in a neutral medium containing 1 M sodium sulfate. The highest energy density, specific capacitance, and power density values of 13.1 Wh kg−1, 455 F g−1, and 279 W kg−1 were achieved for the Pth/n-rGO nanocomposite. The Pth/n-rGO electrode also revealed commendable cyclic stability which it maintained 94% of its original specific capacitance and 125% coulombic efficiency during 1500 galvanostatic charge-discharge cycles. The superior charge-storage property of Pth/n-rGO is ascribed to the double-layer/pseudocapacitance charge storage synergistic effect. By considering the results of performance and stability for the Pth/n-rGO nanocomposite in this study, it could be good candidate for development of new supercapacitors electrode material.

MOP-18-Derived CuO Fiber for Hybrid Supercapacitor Electrodes.

This study explores a simple method of fabricating hybrid supercapacitor electrodes, which could potentially broaden the application of this technology. The method involves electrospinning a uniform solution of Matrimid/Metal-Organic Polyhedra 18 (MOP-18) followed by carbonization at a relatively low temperature of 700 °C in air, rather than in an inert atmosphere, to create free-standing, redox-active hybrid supercapacitor electrodes. Additionally, the synthesis procedure requires no stabilization or activation steps, which enhances the cost effectiveness of the synthesized electrode materials. The resulting C/CuO composite was used as the working electrode, with a polyacrylonitrile (PAN)/Poly(methyl methacrylate) (PMMA) carbon nanofiber (CNF) electrode as the counter and 6 M KOH as the electrolyte in a T-cell configuration. The cell performance and redox activity were evaluated using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), electrochemical impedance spectroscopy (EIS) and cycling stability tests. Additionally, the physical and chemical structures of the electrode materials were assessed using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron spectroscopy (TEM), X-ray diffractometry (PXRD), surface area analysis and other characterization techniques. The electrode material demonstrated a specific capacitance of up to 206 F/g. Supercapacitors utilizing this material display an energy density of 10.3 Wh/kg (active material) at a current density of 1 A/g in electrochemical testing.

Cobalt phosphate-benzene-1,3,5-tricarboxylic acid metal–organic framework @ reduced graphene oxide electrodes for hybrid supercapacitors

Cobalt phosphate-benzene-1,3,5-tricarboxylic acid metal–organic framework @ reduced graphene oxide electrodes for hybrid supercapacitors

Extrinsic Pseudocapacitive NiSe/rGO/g-C3N4 Nanocomposite for High-Performance Hybrid Supercapacitors.

Battery-type materials with ultrahigh energy density show great potential for hybrid supercapacitors (HSCs). In this work, we have developed a nickel selenide (NiSe)/reduced graphene oxide (rGO)/graphitic carbon nitride (g-C3N4) ternary composite as a promising positive electrode for hybrid supercapacitors (HSCs). The extended π-conjugated planar layers of g-C3N4 promote strong interconnectivity with rGO, which further enhances surface area, surface free energy, and efficient electron/ionic path. Additionally, it establishes clear ion diffusion pathways, serving as ion reservoirs during charge and discharge and facilitating efficient redox reactions. As a result, the NiSe/g-C3N4/rGO nanocomposite electrode displayed a specific capacity of 412.6 mA h g-1 at 1 A g-1. Later, the HSC device was assembled using the nanocomposite as the positive electrode and activated carbon as the negative electrode, which delivered an energy density of 65.2 Wh kg-1 at a power density of 750 W kg-1. Notably, the HSC device maintained excellent cyclic stability, preserving 93.3% of its initial performance and Coulombic efficiency of 86.6% for 10,000 charge-discharge cycles at 5 A g-1. These findings underscore the potential utility of NiSe/g-C3N4/rGO as a versatile and effective electrode material for the strategic development of HSC devices.

Optimization of the Porous Structure of Carbon Electrodes for Hybrid Supercapacitors with a Redox Electrolyte Based on Potassium Bromide

This work investigates the electrochemical behavior of hybrid supercapacitors with carbon-based electrodes of different porosity using 5M NaNO3 + 0.5M KBr electrolyte to optimize energy storage processes. Three types of carbon materials were synthesized: activated carbon from rice husk (RH) with a specific surface area of ~2300 m2/g and pore size < 1 nm, and templated carbons from magnesium citrate (MP-8) and glucose with SiO2 as a template (G7), having surface areas of 1976 and 1320 m2/g and pore sizes of 3.4 and 7 nm, respectively. The microporous structure of activated carbon (AC) obtained from RH shows limitations in the diffusion of electrolyte ions, which affects the charge-discharge kinetics. In contrast, the larger mesoporous structures of templated carbons promoted better adsorption and ion transport, significantly affecting the dynamics of redox reactions. The RH/MP-8 hybrid capacitor, combining high surface area and large pore size, demonstrated a 54% increase in specific capacitance, 128% increase in specific energy and 51% increase in energy efficiency at high current densities of 5 A/g, comparing to the symmetric RH/RH hybrid capacitor. This study highlights the critical importance of the relationship between electrode pore structure and electrolyte composition for optimizing supercapacitor performance, which provides valuable information for the development of efficient energy storage technologies.

Challenges and Opportunities: Conducting Polymer‐Graphene based Nanocomposites of Metal Oxides and Metal Sulfides for Supercapacitors

AbstractSupercapacitor's demand for hybrid vehicles, portable electronic gadgets, and high‐power applications is increasing unexpectedly. However, supercapacitors′ inadequacies (i. e., inflated costs, poor energy density, erratic cycle life) need to be addressed by introducing novel composite materials and developing facile synthesis techniques which can give them high surface area and improved electrochemical stability. Moreover, hybrid supercapacitor electrodes based on ternary composites should be designed to broaden their application range and to deal with the challenges. The primary aim of this review is to explore the recent advances in the field of hybrid supercapacitors to address the challenges in this field. Specifically, we have focused on ternary nanocomposites comprising Graphene‐Conducting Polymers‐Metal Oxides (G‐CPs‐MOs) and Graphene‐Conducting Polymers‐Metal Sulfides (G‐CPs‐MSs). Our investigations centred around exploring various synthesis techniques, the surface morphology of composites and analysing the reported electrochemical evaluations of supercapacitor electrodes to highlight the potential prospects and challenges they present.

Investigation of Zn-to-Co Chemometric Ratio in Zinc Cobaltite Spinel as Battery-Type Superior Redox-Active Electrodes for Hybrid Supercapacitors: Density Functional Theory Analysis

Investigation of Zn-to-Co Chemometric Ratio in Zinc Cobaltite Spinel as Battery-Type Superior Redox-Active Electrodes for Hybrid Supercapacitors: Density Functional Theory Analysis

Efficient and eco-friendly preparation of N/P/O co-doped porous carbon electrode for zinc-ion hybrid supercapacitors by laser carbonization

The incorporation of heteroatoms into carbon materials confers advantages in the development of electrode materials for zinc-ion supercapacitors with superior electrochemical performance. However, the conventional carbonization process requires a large thermal power input and is characterized by complexity, high costs, and lengthy reaction times. In this work, the phytic acid-doped polypyrrole (P-PPy) was carbonized via laser irradiation to synthesize N, P, O co-doped porous carbon (P-NOPC), wherein phytic acid served as the source of phosphorus and oxygen, while PPy served as the porous carbon precursor and nitrogen source. The formation of porous carbon can provide a large specific surface area for ion adsorption. The doping of heteroatoms improves the hydrophilicity of porous carbon electrodes and also improves the chemisorption capacity of carbon materials. The aqueous zinc-ion hybrid supercapacitor (ZHSC) based on 0.6P-NOPC9 positive electrode and zinc foil negative electrode has a discharge capacity of 148.0 mAh g−1 in a voltage window of 0.2–1.8 V at 0.1 A g−1, a high energy density (118.2 Wh kg−1) and long cycle life (capacity retention of 98.5% after 10,000 cycles). In addition, the capacity retention of the flexible quasi-solid-state ZHSC is 97.8% after 10,000 cycles. This study can provide a reference for the feasible design of porous carbon electrodes with high performance.

The Effect of Nitrogen on the Capacitive Properties of N-Doped rGO/CuCr<sub>2</sub>O<sub>4</sub> Composites as Materials for Supercapacitors

A hybrid supercapacitor is an energy storage device that combines the properties of EDLCs and pseudocapacitors. In this research, the goal was to analyze the effect of hydrothermal temperature on the structure, morphology, and capacitive properties of the N-Doped reduced graphene oxide/Copper Chromite (N-Doped rGO/CuCr2O4) composite, which was being investigated as a potential material for hybrid supercapacitor electrodes. The method used was hydrothermal, with temperature variations of 120°C, 140°C, and 160°C. The structure and morphology of the composites were analyzed using Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray Analysis (EDX), X-Ray Diffractometer (XRD), and Fourier Transform Infrared Spectrometer (FTIR). Meanwhile, the capacitance and conductivity values of N-doped rGO/CuCr2O4 were measured using Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) tests. The results of the XRD tests showed that an increase in temperature led to a greater dspacing value, indicating the presence of more substituted nitrogen atoms. This was supported by the results from EDX, which showed that the sample with a hydrothermal temperature of 160°C had the largest percentage of nitrogen. Nitrogen is important in increasing the conductivity of the material. The FTIR results revealed a covalent bond between Carbon (C) and Nitrogen (N). Meanwhile, the results of the CV test, performed at a scan rate of 5 mV/s and a potential window of 0-0.8 V, showed that the specific capacitance values were 99.5, 196.16, and 221.59 Fg-1 for the samples with hydrothermal temperatures of 120°C, 140°C, and 160°C, respectively. The EIS test measured the conductivity values of the samples, which were 0.123, 0.518, and 0.549 S/m for the samples with hydrothermal temperatures of 120°C, 140°C, and 160°C, respectively. Thus, the specific capacitance values were influenced by the electrical conductivity of the materials and the nitrogen doping content in the electrode composite material.

Temperature-Dependent Electrochemical Performance of Ta-Substituted SrCoO3 Perovskite for Supercapacitors.

Developing new electrode materials with good temperature-dependent electrochemical performance has become a great issue for the deployment of hybrid supercapacitors with wide temperature tolerance. In this work, a series of Ta-substituted SrCo1-x Tax O3-δ (x=0.05, 0.10, 0.15, 0.20) perovskites have been studied as positive electrodes for hybrid supercapacitors in terms of their structures, elemental valence states and electrochemical performances. Incorporating Ta into SrCoO3-δ perovskite not only stabilizes the crystallite structure but also notably improves electrochemical activities. The SrCo0.95 Ta0.05 O3-δ @CC delivers the highest specific capacity (Qsp ) of 227.91 C g-1 at 1 A g-1 , which is attributed to the highest oxygen vacancy content and the fastest oxygen diffusion kinetics. The hybrid supercapacitor SrCo0.95 Ta0.05 O3-δ @CC//AC@CC exhibits a high energy density of 22.82 Wh kg-1 @775.09 W kg-1 and a stable long-term cycle life (5000 cycles) with 90.7 % capacity retention. As temperature increases from 25 to 85 °C, the capacitance properties are improved at elevated temperatures for both electrode and device due to the increased electrolyte conductivity. The outstanding electrochemical results present that SrCo1-x Tax O3-δ perovskite holds good prospects for hybrid supercapacitors with wide temperature tolerance.

Binder-free cobalt-doped Cu7S4 nanorods as electrode for hybrid supercapacitor with high power density and stable cyclability

Copper-based transition metal sulfides are regarded as good supercapacitor electrode materials due to their cost-effectiveness and considerable theoretical capacity. However, their cycle stability, energy density and rate performance need to be improved. Herein, cobalt-doped Cu7S4 (Co-Cu7S4) nanorods are synthesized at room temperature using environment-friendly routes of co-precipitation and self-sacrifice template processes. Results obtained from electrochemical characterizations and density functional theory calculations can prove the excellent doping kinetics and ideal electrochemical behavior of cobalt ions. Impressively, a high specific capacity of 1302.0 C g−1 (2367.3 F g-1) at 4 A g−1 and rate capabilities of 90.0 % at 10 A g−1 and 61.8 % at 40 A g−1 are obtained. The assembled hybrid supercapacitor (Co-Cu7S4//Active carbon) exhibited superior cycle stability with no insignificant decay after 40,000 charge/discharge process at 5 A g−1 and 20 A g−1, and a maximum power density of 20.4 kW kg−1 at 17.6 Wh kg−1. These excellent electrochemical properties can be ascribed to the porous nanostructures formed by shrinkage during the sulfide process, the rapid electrochemical kinetics, as well as the synergistic effect due to the cobalt ions. This study can provide useful insight into the design and development of electrode materials for high-performance energy storage devices.

Porous carbon derived from a by-product of traditional Chinese medicine for high-performance aqueous zinc-ion hybrid supercapacitors

The rational utilization of biomass waste for the production of usable energy holds immense significance. The present study proposes the effective utilization of a byproduct derived from traditional Chinese medicine, specifically momordica grosvenori shell, as a precursor for fabricating high-performance porous carbon electrodes in rechargeable aqueous zinc ion supercapacitors. The MGCx-T electrodes are prepared by KOH activation and carbonization with MG (momordica grosvenori shell). The influence of KOH addition amount and carbonization temperature on the properties of the prepared materials were studied. Resulting that MGC3–800 has good electrical conductivity, high specific surface area (1141 m2 g−1) and abundant pore structure. The maximum specific capacity reaches 228.7 mAh g−1 at 0.2 A g−1 in 2 M ZnSO4 electrolyte. In the gelatin/ZnSO4 electrolyte, the specific capacity reaches a maximum of 186.1 mAh g−1. Additionally, it exhibits an energy density of 167.5 Wh kg−1 and a power density of 6300 W kg−1. Furthermore, exceptional cycling stability is observed with a capacity retention rate of 92.6 % after 10,000 cycles. Hence, the realization of an industry-effective strategy that not only utilizes biomass waste, but also produces high-performance zinc-ion hybrid supercapacitor electrodes has been achieved.

Binder-Free Defective Bimetallic Metal-Organic Framework Nanostructures with Lattice Distortion as Hybrid Supercapacitor Electrodes

Binder-Free Defective Bimetallic Metal-Organic Framework Nanostructures with Lattice Distortion as Hybrid Supercapacitor Electrodes