Electrode Material For High-performance Supercapacitors Research Articles

Facile route to high-mass-loading amorphous NiCo-MOFs as high-performance electrode materials for asymmetric supercapacitors

In the current work, synthesis of an amorphous NiCo-MOF with an ultra-high mass loading (10.3 mg cm−2) and an ultra-thick plate structure was achieved via a one-step solvothermal method.

A high mass loading flexible electrode with a sheet-like Mn3O4/NiMoO4@NiCo LDH on a carbon cloth for supercapacitors.

Mass loading is an important parameter to evaluate the application potential of active materials in high-capacity supercapacitors. Synthesizing active materials with high mass loading is a promising strategy to improve high performance energy storage devices. Preparing electrode materials with a porous structure is of significance to overcome the disadvantages brought by high mass loading. In this work, a Mn3O4/NiMoO4@NiCo layered double hydroxide (MO/NMO/NiCo LDH) positive electrode is fabricated on a carbon cloth with a high mass loading of 20.4 mg cm-2. The MO/NMO/NiCo LDH presents as a special three-dimensional porous nanostructure and exhibits a high specific capacitance of 815 F g-1 at 1 A g-1. Impressively, the flexible supercapacitor based on the MO/NMO/NiCo LDH positive electrode and an AC negative electrode delivers a maximum energy density of 22.5 W h kg-1 and a power density of 8730 W kg-1. It also retains 60.84% of the original specific capacitance after bending to 180° 600 times. Moreover, it exhibits 76.92% capacitance retention after 15 000 charge/discharge cycles. These results make MO/NMO/NiCo LDH one of the most attractive candidates of positive electrode materials for high-performance flexible supercapacitors.

Fabrication of tobacco-stem-derived hierarchical porous carbon via synergistic gas exfoliation effect for high-performance supercapacitors

The high-value utilization of agricultural and forestry waste holds the promise of alleviating the issues of energy crisis. Among them, the manufacturing of high-performance supercapacitor electrode materials from tobacco waste biomass is a reliable avenue. In this work, tobacco-stem-derived hierarchical porous carbon (TS-HPC) was prepared by one-pot ball milling and carbonization using calcium carbonate (CaCO3) and potassium oxalate (K2C2O4) as mild activating agents. Due to the synergistic activation of CaCO3 and K2C2O4, the specific surface area of TS-HPC is 2749 m2/g. TS-HPC with the hierarchical porous structure greatly shows an excellent specific capacitance (402 F/g at 0.5 A/g) in the three-electrode configuration. In addition, symmetric supercapacitor based on TS-HPC exhibits 10.2 W h/kg energy density at 150.0 W/kg power density, together with outstanding cycling stability (remains 97.8% after 10,000 cycles). Moreover, we demonstrated that the gas exfoliation of CaCO3 and K2C2O4 could contribute to the formation of hierarchical porous structures with a synergistic activation effect. This work could provide a new perspective on the preparation of biomass-derived carbon as electrode for supercapacitors.

MoSe2-FeOOH nanocomposite as hybrid electrode material for high-performance symmetric supercapacitor

Molybdenum diselenide-based composite has been considered a potential material in the supercapacitor application due to its variable oxidation states, high surface area, and electronic conductivity. This report presents the composite formation of molybdenum diselenide nanoflowers and iron oxide-hydroxide nanorods utilizing a hydrothermal route assisted by room temperature chemical blending technique. The symmetric cell designed based on prepared composite material delivers the specific capacitance of 132 F g−1 for 1 A g−1 for a 1 V voltage. It shows 100% capacitance retention for 3000 cycles and 100% coulombic efficiency for 10,000 cycles at 1 A g−1. It provides an energy density of 18.3 Wh kg−1 at 1174 W kg−1 power density. The practical application associated with the designed symmetric cell based on the composite electrode was confirmed via the illumination of the panel comprising 42 red LEDs for 10 min effortlessly without break. Additionally, a self-proposed charge mechanism has been incorporated for an enhanced understanding of the reader. The improved results indicate the point that the prepared electrode material has good capability for high-performance supercapacitors.

Graphene oxide@Fe3o4@Tungstate modified ionic liquid as a novel electrode material for high-performance supercapacitor

In this study, using Fe3O4, graphene oxide (GO), Na2WO4, and ionic liquid (IL), GO@ Fe3O4-IL-W as a novel nanocomposite has been synthesized to obtain a high-performance supercapacitor. The morphologies and structures of materials have been characterized by Fourier-transform infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TGA), X-ray diffraction (XRD), vibrating-sample magnetometer (VSM), scanning electron microscopy (FESEM), and energy diffraction X-ray (EDX) analysis. The behavior of electrochemical and supercapacitive nanocomposite has been investigated using cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS). The fabricated electrode material exhibited high specific capacitance (332.45 F/g at 0.2 A/g) and excellent electrochemical performance based on the cyclic stability (capacitance retention of 91.3% after 10,000 cycles). Furthermore, a symmetric supercapacitor device based on GO@ Fe3O4-IL-W was successfully assembled and an energy density of 7.38 Wh/kg at a power density of 40 W/kg has been obtained. Consequently, the GO@ Fe3O4-IL-W nanocomposite electrode material is expected to be a promising material for supercapacitor applications and other energy devices.

MnO2 nanospheres integrated into hierarchical porous carbon as electrode for high performance asymmetrical supercapacitors

Hierarchical porous carbon (HPC) is considered as an ideal electrode material for supercapacitors on account of its high stability and developed pore structure. MnO2, possessing ultrahigh theoretical capacitance, can provides pseudocapacitance to facilitate electrochemical performances. Herein, HPC with large specific surface area (1153 m2 g−1) and abundant mesopores (95.76 % mesopore ratio) is prepared via ZnCl2 activation, which can act as the support and substrate for MnO2. Subsequently, in-situ synthesis of MnO2 nanospheres and preparation of MnO2/HPC composites (MnO2@HPCs) are realized simultaneously by a simple redox reaction. Benefiting from high conductivity of HPC (4.07 S m−1) and moderate size of MnO2 nanospheres (∼40–50 nm), MnO2@HPCs exhibit an excellent specific capacitance (521 F g−1 at 0.5 A g−1 and 468 F g−1 at 1 mV s−1) and pseudocapacitance effect in three-electrode system. Further, the asymmetric supercapacitor adopting MnO2@HPC160 and HPC as the cathode and anode delivers a superior capacitance value (74 F g−1 at 0.5 A g−1), outstanding rate performance (79.7 % at 10 A g−1) and remarkable energy density of 32.93 Wh kg−1 in 1 M Li2SO4 electrolyte. These results demonstrate that the MnO2/hierarchical porous carbon composite is a promising candidate as electrode material for high-performance supercapacitors.

Nanostructured Titanium Nitride and Its Composites as High-Performance Supercapacitor Electrode Material.

Electrochemical supercapacitors as an energy storage device have become trademark in current electronic, medical and industrial applications, as they are sources of impressive power output. Supercapacitors supply fast power output, suitable to cover the energy demand of future electronic devices. Electrode material design is a subject of intense research in the area of energy development and advancement, due to its essential role in the electrochemical process of charge storage and the cost of capacitors. The nano-dimensions allow for more electroactive sites, different pore size distributions, and a large specific surface area, making nanostructured electrode materials more promising. Electrode materials based on metal oxides, metal nitrides, and metal carbides are considered ideal for highly efficient electrochemical supercapacitors. Recently, much effort has been devoted to metal nitride-based electrodes and their diverse compositions as they possess higher electrical conductivity and better corrosion resistance, electrochemical stability, and chemical reactivity. Among these, titanium nitride (TiN), possesses high electrochemical stability, outstanding electrical conductivity, and a unique electronic structure. Nanocomposites based on titanium nitrides are known to deliver higher electrochemical performance than pristine nanostructured TiNs due to potential synergetic effects from both the materials. In this paper, recent advancements made in the field of nanostructural TiN electrode materials for SCs are reviewed along with their challenges and future opportunities. Additionally, some of the major techniques involved in the synthesis process are discussed, along with some basic concepts.

Three-dimensional unified electrode design using CuO embedded MnO2 Nano-dandelions@Ni(OH)2 nanoflakes as electrode material for high-performance supercapacitors

In this study, we report successive chemical bath deposition (CBD) method to prepare three-dimensional (3D) hierarchical porous Ni(OH)2 nanoflakes on CuO-doped MnO2 nano-dandelions named as MnO2/CuO@Ni(OH)2 nanorod-nanoflake clusters. The as-prepared hierarchical MnO2/CuO@Ni(OH)2 nanorod-nanoflake clusters were composed of radially grown nanorods with a length of about 1.0 μm and surrounded by the interconnected nanoflakes clusters with a diameter of about 17 nm. Electrochemical evaluations revealed that the as-prepared electrode delivers a high specific capacitance of 3800 mF cm−2 at 1.0 mA cm−2 and long cycle life. The superior electrochemical performances were attributed to ideal ion transfer channels derived from radially grown 1D nanorods, which in combination with battery-type behavior of Ni(OH)2 nanoflakes, afford synergistic and multipurpose effects. Especially, the existence of CuO inner layer in the hierarchical MnO2/CuO@Ni(OH)2 nanorod-nanoflake clusters can fill the Schottky barrier at the interface between MnO2 and Ni(OH)2. This work suggest a new design of metal oxide/hydroxides and indicates that the hierarchical MnO2/CuO@Ni(OH)2 nanorod-nanoflake clusters can be considered as potential electrode material in high-rate supercapacitors.

Cu(OH)2@NiC2O4 core-shell structure: A novel class nanoarrays electrode materials for high-performance supercapacitor

Constructing heterostructured electrode materials is a promising strategy for improving the performance of supercapacitors. However, the performance of existing active materials does not meet the growing demand for energy storage devices. In this study, novel nanoarrays with Cu(OH)2 nanorod cores and nickel oxalate shells were grown on copper foam as electrode materials for boosting the performance of supercapacitors. The synthesized CF@Cu(OH)2@NiC2O4 can reach a specific capacitance of 9.7 F cm− 2 (3 mA cm−2), which presents a good enhancement for the precursor electrode. The asymmetric supercapacitor (ASC) prepared with activated carbon exhibited a high energy density of 0.97 mWh cm−2 (2.4 mW cm−2) and an excellent cycling performance (82.3% retention after 30,000 cycles at 100 mv/s). The improved properties are inferred to be attributed to the construction of the novel electrode with heterostructures. This study provides a new idea that core-shell hybrids with oxalate shells can be used as advanced electrode materials for energy storage applications.

Design of in-situ grown copper-based bimetallic phosphide electrode materials for efficient energy storage

Transition metal compound electrodes are promising in the preparation of high-performance supercapacitors (SCs) due to their significantly enhanced charge mass transfer and rich electrochemical active sites. Possessing a large electrochemical surface area combined with a good conductive copper foam is a way to improve the capacitive performance of the electrode. Here, we report the synthesis of NiCo-P three-dimensional nanosheet structures (expressed as Cu@NCP) on copper foam as a high-performance electrode material for supercapacitors. The presence of multivalent cations in this Cu@NCP electrode material enables abundant redox reactions and promotes synergistic effects. Benefiting from these advantages, the obtained electrode exhibits a high specific capacitance of 1619 C g−1 (at a current density of 1 A g−1), excellent rate capability (1480 C g−1 at a current density of 20 A g−1), and good cycling stability (retains 90.6 % of the initial capacitance after 10,000 cycles at a current density of 10 A g−1). Using Cu@NCP as the cathode of the hybrid supercapacitor and rGO as the anode, showed that the energy density of 31.22 Wh kg−1 at a power density of 400 W kg−1. Not only that, it shows ultrahigh capacity retention (89.5 %) at a current density of 10 A g−1. It is believed that this finding facilitates the design of electrode materials to improve the performance of fast energy storage materials based on transition metal compounds.

Amorphous nanosheets constructed nickel cobalt hydroxysulfide hollow spheres as cathode materials for hybrid supercapacitors

Tailoring architecture and multi-composition of electrode materials via a facile and cost-effective strategy are highly favorable to optimize physiochemical properties for developing energy storage devices. Herein, hierarchical nickel cobalt hydroxysulfide hollow spheres decorated with amorphous nanosheets and dual-ligands (denoted as NiCo-DHS) are synthesized through hydrolysis of self-templating metal alkoxides, followed by room-temperature anionic exchange process. The resultant dual-ligands hydroxysulfide possesses weak metallicity, reduced band gap and enhanced conductivity owing to the electronic regulation of the formed M−OH/S bonds. Additionally, the nanosheet-constructed amorphous structure contributes to accelerating ions diffusion and enlarging specific surface area, further exposing more active sites to enrich redox reactions. Benefiting from the compositional and structural superiorities, the optimized NiCo-DHS-12 electrode presents desirable electrochemical performance, including high specific capacity of 973.6 C g−1 (1 A g−1) and stable durability over 8000 cycles with a small capacity loss of 7.4 % at 10 A g−1. Moreover, the hybrid device assembled with NiCo-DHS-12 and porous activated carbon delivers an energy density of 65.91 Wh kg−1 at a power density of 0.89 kW kg−1 and considerable cycling stability. These encouraging results demonstrate a simple and reliable approach in constructing high-performance electrode materials for advanced supercapacitors in potential.

Biomass-derived inherently doped multifunctional hierarchically porous carbon as an efficient electrode material for high-performance supercapacitors

Biomass-derived inherently doped multifunctional hierarchically porous carbon as an efficient electrode material for high-performance supercapacitors

In Situ Growth of MnO2 Nanosheets on a Graphite Flake as an Effective Binder-Free Electrode for High-Performance Supercapacitors.

In this work, manganese dioxide (MnO2) nanosheets in situ loaded on a high-purity graphite flake (GF) were prepared by one-step hydrothermal deposition. It was found that the specific capacitance value of a single MnO2/GF electrode was 882 F/g at a current density of 1.0 A/g in a KOH electrolyte, and the specific capacitance retention of the MnO2/GF electrode can reach about 90.1% after 5000 charge-discharge cycles at a current density of 10 A/g. Furthermore, a MnO2/GF∥MnO2/GF symmetric supercapacitor device was fabricated with two pieces of MnO2/GF electrodes and ordinary filter paper with a 1 M KOH/PVA gel electrolyte as a separator. The single symmetric device displayed a high energy density of 64.2 Wh/kg at a power density of 400 W/kg within an applied voltage of 1.6 V, and this value was superior to those of previously reported MnO2-based systems. A tandem device consisting of a five-series tandem device (the applied voltage of a single device was 0.7 V) and a three-series tandem device (the applied voltage of a single device was 1.6 V) was prepared to drive a red light-emitting diode (LED). These findings open up application prospects for MnO2-based composite electrode materials for high-performance supercapacitors.

One-step solvothermal synthesis of heterostructured nanocomposite Ni0.85Se/MnSe as the high-performance electrode material for supercapacitors

A facile one-step solvothermal method is developed to prepare heterostructured nanocomposite Ni0.85Se/MnSe. High-resolution transmission microscopy confirms the formation of the heterostructure. When coated onto carbon cloth and used as the electrode material for supercapacitors, the electrode with the optimized Ni0.85Se/MnSe exhibits specific capacity of 1118 C g−1 at the current density of 1 A g−1, and a capacity retention at 83.2% after 5000 charge-discharge cycles at 10 A g−1 in 4 M KOH using three-electrode system. The assembled asymmetric supercapacitor exhibits the specific energy of 49.3 Wh kg−1 at the power density of 799.81 W kg−1, and 97.8% of the initial capacity is retained after 5000 charge-discharge cycles at 5 A g−1. Kinetic study indicates that the major contribution of the capacity is the diffusion-controlled process, and the electrode exhibits battery-type behavior. The excellent charge storage performance is originated from the higher number of electrochemically active sites, improved reaction kinetics and facilitated diffusion that are induced by the charge redistribution at the heterostructure interface. Conversion of the surface metal selenides to oxides and (oxy)hydroxides is observed during the long-term charge-discharge cycling. The heterostructured nanocomposite Ni0.85Se/MnSe is a promising candidate as the electrode material for supercapacitors.

Ternary MnCo2O4/MWCNT/rGO nanocomposites as high-performance supercapacitor electrode materials

In this research, MnCo2O4 nanoparticles and their composites with reduced graphene oxide (rGO), multi-wall carbon nanotube (MWCNT), and MWCNT/rGO were synthesized by a simple hydrothermal method to investigate their performance as supercapacitor electrodes. The crystal structure and morphology of the fabricated materials were studied through X-ray diffraction, field-emission scanning electron microscopy, and transmission electron microscopy. Moreover, electrodes of the samples were prepared by the hydrothermal method to investigate electrochemical properties. Cyclic voltammetry, galvanostatic charge–discharge (GCD), electrochemical impedance spectroscopy, and cyclic stability showed that the MnCo2O4/MWCNT/rGO composite with a high specific capacitance of 3346.6 F g−1 at the current density of 1 A g−1 had the highest capacitance and stability among all samples. The MnCo2O4/MWCNT/rGO electrode remained stable and preserved 91.18% of initial capacitance at the end of 10,000 cycles at the current density of 20 A g−1. This electrode, with a specific surface area of 45.9 m2 g−1 and suitable electrochemistry, has promise as an excellent electrode material for storing energy.

Nitrogen-Rich Porous Carbon/NiMn Hybrids as Electrode Materials for High-Performance Supercapacitors

Nitrogen-Rich Porous Carbon/NiMn Hybrids as Electrode Materials for High-Performance Supercapacitors

Investigation of MnO2/CuO/rGO ternary nanocomposite as electrode material for high-performance supercapacitor

• Various morphologies are interlaced in the development of MnO 2 /CuO/rGO nanomaterials for supercapacitors application. • Significant enhancement of capacitive active sites and encourage electrolyte transport during the electrochemical process. • Showed excellent cycling stability with capacitance retention of 83.74% after 5000 cycles at 10 A/g and high specific capacitance of 658.97 F/g at a current density of 1 A/g. Here, utilising easily available precursor, we technologically advanced a modest and affordable way to form carbon-grounded material interlaced with metal oxides to form a controlled structure. As a hard substrate, interconnect microstructures were built via the in-situ creation of rGO/MnO 2 -rod/CuO-sphere (MCR) nanoparticles, which could significantly enhance capacitive active sites and encourage electrolyte transport during the electrochemical process. The modified sample showed excellent cycling stability with capacitance retention of 83.74% after 5000 cycles at 10 A/g and high specific capacitance of 658.97 F/g at a current density of 1 A/g. Additionally, at an energy density of 118.61 Wh/kg, the supercapacitor made of MCR electrodes demonstrated a power density of 1.5 kW/kg. This research presents a viable method for creating supercapacitor electrodes with great performance.

Solvent-induced molecular structure engineering of lignin for hierarchically porous carbon: Mechanisms and supercapacitive properties

Lignin is considered an ideal precursor for porous carbon materials on account of its rich aromatic entities and high carbon content. Modulating the molecular structure of lignin is of paramount importance in controlling the carbon structure. In this work, a solvent-induced self-assembled strategy is reported to synthesize three porous carbon materials using three typical kinds of lignin as precursors. The influence of lignin molecule structure on the microstructural and electrochemical properties of the as-prepared porous carbons is discussed. Experiment results reveal that the hydrophobic nature of lignin in mixed solvent is the force driving the self-assembly process, determining the porosity, dispersity, and conductivity of the resulting carbon. Among the three as-prepared samples, the carbon obtained from sodium lignosulfonate (LSC) shows a highly-dispersed sheet-like structure with rich hierarchical pores. The LSC shows a high specific capacitance of 305 F g − 1 , suggesting that it can be utilized as a promising electrode material for high-performance supercapacitors. The proposed solvent-induced self-assembly strategy could guide the rational design of other lignin-derived carbon. Synopsis. The molecular structure of lignin has a significant effect on its solution self-assembly. Owing to the intensive pyrolysis synergistic effect induced by the strong hydrophobic bonding, sodium lignosulfonate-derived carbon (LSC) showed the highest specific capacitance. • Biomass byproducts are used to prepare high-value carbon materials. • A green process is developed to prepare high quality hierarchical porous carbon. • The amphiphilic properties of lignin are beneficial to self-assembly regulation. • The microstructure of porous carbon has significant influence on electrochemical performance.

Rose-like ZnNiCo layered double hydroxide grown on Co3O4 nanowire arrays for high energy density flexible supercapacitors

Ternary double layer hydroxides are considered as potential electrode materials for high-performance supercapacitors due to their unique layered structure and synergistic effect among their active components. However, the poor stability of these materials during the redox reaction seriously hinders their practical application. Therefore, it is of practical significance to design highly efficient and facile strategy to solve these issues. Herein, rose-like CC@Co3O4/ZNC-LDH hierarchical structure nanowire arrays are successfully synthesized on carbon cloth by a two-step hydrothermal method combined with a calcination process. Due to the unique structural design and the synergistic effect between Zn, Ni and Co elements, the prepared CC@Co3O4/ZNC-LDH nanocomposites exhibit excellent electrochemical properties (2084 mF cm−2 at 1 mA cm−2) and ideal capacitance retention (86.5 % after 10,000 cycles). In addition, the ASC device assembled with CC@Co3O4/ZNC-LDH nanocomposites as the positive electrode and activated carbon as the negative electrode can provide an energy density of 41 Wh kg−1 and a corresponding power density of 958 W kg−1 in a voltage window of 0–1.7 V. A multifunctional display can be lit up for more than 25 min by connecting two ASC devices in series. Therefore, the prepared rose-like CC@Co3O4/ZNC-LDH electrode with hierarchical structure should have a satisfactory practical application prospect.

One-dimensional curved graphene nanoribbons assisted MoS2 nanosheets enhanced electrode material for high-performance supercapacitor

Curved graphene-nanoribbons@MoS2 hybrid electrode is designed with a hierarchical structure and employed as an electrode for high-performance supercapacitors. Molybdenum disulphide (MoS2) was prepared via hydrothermal method. The XRD result of MoS2 showed hexagonal phase.Hummer’s method and reduction process lead to the unzipping of MWCNTs to curved graphene nanoribbons (CGNs). The CGNs were confirmed by the 2θ value, which was located at 26.05° and it was shifted to 23.2°. As prepared CGNs@MoS2 electrode shows better performance and delivered a high specific capacitance of 282F/g @1 A/g also it delivered 78% of specific capacitance over 5000 cycles at a current density of 10 A/g.