High-energy Capacitors Research Articles

High Energy and Power Zinc Ion Capacitors: A Dual-Ion Adsorption and Reversible Chemical Adsorption Coupling Mechanism.

Zinc ion capacitors (ZICs) hold great promise in large-scale energy storage by inheriting the superiorities of zinc ion batteries and supercapacitors. However, the mismatch of kinetics and capacity between a Zn anode and a capacitive-type cathode is still the Achilles' heel of this technology. Herein, porous carbons are fabricated by using tetra-alkali metal pyromellitic acid salts as precursors through a carbonization/self-activation procedure for enhancing zinc ion storage. The optimized rubidium-activated porous carbon (RbPC) is verified to hold immense surface area, suitable porosity structure, massive lattice defects, and luxuriant oxygen functional groups. These structural and compositional merits endow RbPC with the promoted zinc ion storage capability and more matchable kinetics and capacity with a Zn anode. Consequently, RbPC-based ZIC delivers a high specific energy of 178.2 W h kg-1 and a peak power density of 72.3 kW kg-1. A systematic ex situ characterization analysis coupled with in situ electrochemical quartz crystal microbalance tests reveal that the preeminent zinc ion storage properties are ascribed to the synergistic effect of the dual-ion adsorption and reversible chemical adsorption of RbPC. This work provides an efficient strategy to the rational design and construction of high-performance electrodes for ZICs and furthers the fundamental understanding of their charge storage mechanisms or extends the understanding toward other electrochemical energy storage devices.

Extraordinary Compatibility to Mass Loading and Rate Capability of Hierarchically Porous Carbon Nanorods Electrode Derived from the Waste Tire Pyrolysis Oil

The conversion of waste tire pyrolysis oil (WTPO) into S‐doped porous carbon nanorods (labeled as WPCNs) with hierarchical pore structure is realized by a simple template‐directed approach. The specific surface area of as‐obtained porous carbon nanorods can reach up to 1448 m2 g−1 without the addition of any activating agent. As the capacitive electrode, WPCNs possess the extraordinary compatibility to capacitance, different electrolyte systems as well as long‐term cycle life even at a commercial‐level areal mass loading (10 mg cm−2). Besides, only an extremely small capacitance fluctuation is observed under the extreme circumstance (−40 to 80 °C), reflecting the excellent high‐ and low‐temperature performance. The relationship between the pore structure and capacitive behavior is analyzed by comparing WPCNs with mesopores‐dominated asphalt‐derived porous carbon nanorods (APCNs) and micropores‐dominated activated carbon. The molecular dynamics simulation further reveals the ion diffusion and transfer ability of the as‐prepared carbon materials under different pore size distribution. The total ion flow (NT) of WPCNs calculated by the simulation is obviously larger than APCNs and the NT ratio between them is similar with the experimental average capacitance ratio. Furthermore, this work also provides a valuable strategy to prepare the electrode material with high capacitive energy storage ability through the high value‐added utilization of WTPO.

Pre-lithiated Li4+xTi5O12 (0 ≤ x ≤ 3) anodes towards building high-performance Li-ion capacitors

A 180° faradaic shift is observed for a completely pre-lithiated Li4Ti5O12 anode when paired with an activated carbon cathode. The optimum range of pre-lithiation certainly enables attaining high energy and high power Li-ion capacitors.

High energy and power lithium-ion capacitor based on MnO-encased graphene spheres anode and hollow carbon nano-rods cathode

High energy density, high power density and long lifespan lithium-ion capacitors (LICs) are increasing required in many electronic devices. However, the mismatch of capacity severely hinders the practical applications of LICs. Herein, hollow MnO@graphene nano-spheres (MnO@G-NS) are prepared by a high temperature calcination treatment of the hydrothermally-synthesized MnCO3-C spheres. The MnO@G-NS anode shows high capacity, outstanding rate performance (504 mAh g−1 at 3 A g−1), high initial coulombic efficiency (83.6%) and long lifespan cyclic stability. Meanwhile, S, N-codoped hollow carbon nano-rods (SNHCs) are obtained via a template-free calcination process. As the cathode, SNHCs displays high capacitiy, excellent rate capability (165 mAh g−1 at 10 A g−1) and ultralong cycling stability for 5000 cycles. Furthermore, MnO@G-NS//SNHCs is assembled by MnO@G-NS anode and SNHCs cathode, and delivers high energy density (126.7 Wh kg−1), high power density (5722 W kg−1) and long-term cycling stability for 10,000 cycles. Furthermore, a highly loaded (18 mg cm−2) LICs still delivered a high energy density of 111 Wh kg−1 at 999.4 W kg−1, and a higher power density of 5095.1 W kg−1 at 63.7 Wh kg−1 coupled with 81% capacity retention for 10,000 cycles at 10 A g−1, indicating a great application potential in LICs.

A high-energy density hybrid capacitor derived from a graphite-oxide lithium primary battery

A high-energy density hybrid capacitor derived from a graphite-oxide lithium primary battery

Identifying Heteroatomic and Defective Sites in Carbon with Dual-Ion Adsorption Capability for High Energy and Power Zinc Ion Capacitor

HighlightsA unique dual-ion adsorption mechanism for zinc ion capacitor is enabled by a carbon cathode with defect-rich tissue, dense heteroatom dopant and immense surface area.The active sites on carbon surface for reversible dual-ion adsorption are identified by in-depth characterizations and DFT simulations.The zinc ion capacitor delivers unrivaled combination of high energy and power characteristics. The superb energy, power and cyclability are achieved in multiple cell configurations including coin cell and flexible solid-state pouch-/cable-type cells.

High-Coulomb Switches and Their Applications in Pulsed Power (Review)

High-current high-voltage closing switches are the key components of pulsed power systems based on high-energy capacitor banks. Spark-gap switches are the most used today due to their relatively simple design, reliability, and ease of maintenance and repair. The main disadvantage of spark gaps is their limited service life, which is directly or indirectly related to electrode erosion. To prevent this erosion, multichannel switches and switches with the movement of the discharge channel were proposed. In this review, both types of switches are considered and in both cases, the Department of pulsed technology of the Institute of High Current Electronics occupies a leading position in the world in their development.

Nanostructured Co3O4 for achieving high-performance supercapacitor

Supercapacitors with cobalt oxide (Co3O4) electrode are a kind of strong candidates for achieving high-capacity storage energy devices. However, the reported capacitances lower than the theoretical values are undesirable. In this study, a high-performance supercapacitor by using the Co3O4 electrode with a porous nanostructure is enabled by the calcination treatment of metal organic framework ZIF-67. Of note, the resulting Co3O4 electrodes shows high specific capacitance of 1015 F/g under a current density of 1 A/g. Additionally, it exhibits energy density of 36.6 Wh/kg at a power density of 189.5 W/kg and maintains capacitance retention of 78.2% after 5000 cycles at 8 A/g. The strategy proposed here provides a good way to synthesize nanostructured Co3O4, a candidate for constructing high-capacitance energy storage devices.

High action gas switches.

High action, high voltage closing switches are the key components of pulsed power systems based on high energy capacitor banks, primarily used for high power lasers, electromagnetic accelerators, high pulsed magnetic field facilities, crushing materials, and electromagnetic compatibility tests. There are several options for closing switches, including ignitrons, vacuum switches, pseudo-spark switches, solid-state switches, and high pressure gas switches (spark gaps). Spark switches are currently the most used due to their relatively simple design, reliability, and ease of maintenance and repair. The main disadvantage of spark gaps is a limited lifetime, which is directly or indirectly related to the erosion of the electrodes. To prevent erosion of the electrodes, multichannel switches and switches with movement of the discharge channel were proposed. In this Review, both types of switches are considered.

Synthesis and characterization of self-healable poly (acrylamide) hydrogel electrolytes and their application in fabrication of aqueous supercapacitors

With overwhelming progress in the field of electronic technology, self-healable hydrogel electrolyte-based supercapacitors are of significant interest as a power source in wearable energy storage devices. Self-healable hydrogel with unique three-dimensional porous microstructure, unprecedented self-healing, high capacitive energy density, low power density has been synthesized by in situ polymerization of acrylamide in the presence of exfoliated sodium montmorillonite (Na-MMT) clay as non-covalent cross-linker. Furthermore, addition of lithium trifluoromethanesulfonate (LiTF) salt converted the hydrogel into electrolyte for use in supercapacitor. Hydrogel electrolytes were prepared containing 10, 20, 30, and 40 wt% salt (AAM1, AAM2, AAM3, and AAM4), respectively. Acrylamide, clay and salt interactions were explored by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM) and energy dispersive x-ray analysis (EDX). X-ray diffraction (XRD) analysis reveals amorphous nature whereas FTIR and transference number measurements prove the complexation and presence of ionic species in the hydrogel electrolytes. Ionic conductivity and transport studies for hydrogel electrolyte containing 30 wt% of LiTF showed maximum ionic conductivity of 9.34 × 10−3 S/cm and number density of 70.7 × 10 20 cm−3, diffusion coefficient of 2.16 × 10 −9 cm2/s, ionic mobility of 0.854 × 10−7 cm2/V.s among all the synthesized hydrogel electrolytes. The electrochemical performance of the fabricated device disclosed the maximum significant specific capacitance of 102 F/g at 3 mV/s and 157 F/g at 50 mA/g along with power density of 50 W/kg and energy density of 21.59 W h/Kg, respectively for hydrogel electrolyte (AAM3) containing 30 wt% of the LiTF. Self-healing properties of hydrogel electrolyte have been confirmed by its use in supercapacitor where it retained its self-healing properties. The self-healable supercapacitor was used to light up 2 V light emitting diode (LED). Hence, investigations suggest the potential application of the hydrogel electrolytes with 30 wt% LiTF in the supercapacitors.

Configurational approach to the enhancement of the dielectric properties and energy density of polyvinylidene fluoride-based polymer composites

Polyvinylidene fluoride (PVDF)-based polymers are promising dielectric materials, owing to their higher breakdown strength and energy density than conventional ceramic-based dielectric materials. Nevertheless, the energy density of the polymers is lower than expected, highlighting the need for improvement before they can be applied commercially. As one method to solve this issue, the P(VDF-HFP) copolymer and P(VDF-TrFE-CFE) terpolymer have been mixed at various compositions, because both the high breakdown strength of the copolymer and the dielectric constant of the terpolymer can be combined. Depending on the configuration of the two polymers, such as the 3–3 composite or 2–2 composite, the strength of their properties also contributes differently. From blended films of a 3–3 composite, P(VDF-TrFE-CFE) terpolymer and P(VDF-HFP) copolymer films with a 9:1 composition showed the highest energy storage capability as well as excellent dielectric properties. The remnant polarization and breakdown strength of the blended films were 1.83 µC cm−2 and 250 MV m−1, respectively. Multilayered films of the 2–2 composite with the same composition exhibited a considerable energy storage of 40 J cm−3 owing to the low remnant polarization of 5.15 µC cm−2 and large breakdown strength of 500 MV m−1. Consequently, multilayered PVDF-based polymer films showed good potential for high power energy and electrostatic capacitor applications because of their remarkable energy density and breakdown strength.

Graphene foam–based electrochemical capacitors

Electrochemical capacitors (ECs) are a promising technology for energy storage, and future development of sustainable electrode materials is critical to developing these devices. The recent progress and earnest motivation to develop high specific energy capacitors commercially for the emerging market and electronics industry, coupled with the significance and popularity of graphene foam (GF)–based electrode materials in the preparation of functional capacitors have been crucially explored in this review. The review outlines the current disposition and headways in GF-based ECs' technology. Besides, owing to its three-dimensional interconnected hierarchical form alongside the physicochemical distinctions, GF has been regarded as one to curtail some bottlenecks regarding graphene dispersion/restacking in nanocomposite materials. Some of the various techniques to synthesizing high-grade GF that can enable higher energy density of ECs, as well as some key material's features of GF that enhance various performances of the material's composite have also been reviewed.

Percolation phenomena of dielectric permittivity of a microwave-sintered BaTiO3–Ag nanocomposite for high energy capacitor

In the present study, the Alkoxide-Hydroxide sol-gel process is utilized for the synthesis of barium titanate-silver (BaTiO3–Ag) nanocomposite in an inert atmosphere. The high value of dielectric constant having less tangent loss is obtained along with increasing conductivity with Ag content. Moreover, by the inclusion of the conductive phase in BaTiO3, the increasing value of dielectric properties with decreasing Curie temperature is investigated. Sintering of composites was done at 1100 °C for 20 min by using microwave sintering, to improve the densification of ceramic nanocomposites in lesser time with uniform grain size. By increasing the silver content, dielectric constant and tangent loss increased until the percolation threshold (∼5% Ag) achieved and suppression of formation of conducting path in composite occurred due to adhesion of silver on barium titanate. Also, at Tc in BaTiO3–Ag (3.5%), the highest value of dielectric constant (εr) (∼9 × 104 with tangent loss ∼0.06; several times larger than pure BaTiO3) was obtained due to well dispersion of silver particles in BaTiO3 matrix.

Self-assembling NiCo2S4 nanorods arrays and T-Nb2O5 nanosheets/three-dimensional nitrogen-doped garphene hybrid nanoarchitectures for advanced asymmetric supercapacitor

Abstract In this study, NiCo2S4 nanorods arrays on nickel foam (NiCo2S4/NF) have been developed using a simple solvothermal method and T-Nb2O5 nanosheets/three-dimensional nitrogen-doped graphene hybrid (T-Nb2O5/3DNG) have been synthesized by hydrothermal accompanying an annealing calcination treatment. In a three-electrode system, NiCo2S4/NF nanorod and T-Nb2O5/3DNG electrodes display excellent specific capacitances of 1709.2 F g−1 and 952.7 F g−1 at the current density of 1 A g−1, respectively, with the capacitance retention of 93.1% and 90.8% after 5000 cycles. Furthermore, a hybrid asymmetric supercapacitor device consisting of a binder-free NiCo2S4/NF nanorods arrays as a positive electrode and T-Nb2O5/3DNG as a negative electrode in 6 M KOH electrolyte is designed, which exhibits an expanded potential voltage window up to 1.8 V, presents extremely high capacitance of 203.4 F g−1 at 0.5A g−1 and a remarkable energy density of 45.4 Wh kg−1 while delivering a power density of 9568.3 Wkg−1. Encouragingly, the device also delivers outstanding cycling stability of 93.6% and a coulombic efficiency close to 100% after 10,000 charge-discharge cycles. This strategy for the reasonable design of the efficient positive and negative electrode materials provides a promising route for asymmetric supercapacitor and opens new avenues with production of high energy and long life capacitor equipment in modern electronic industries.

All-Solid-State Electrospun Poly(vinylidene fluoride-co-hexafluoropropylene)/Li7.1La3Ba0.05Zr1.95O12 Nanohybrid Membrane Electrolyte for High-Energy Li-Ion Capacitors

Herein, we prepared all-solid-state electrospun poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)/Li7.1La3Ba0.05Zr1.95O12 nanohybrid membrane electrolytes (esHPMEs) by an electrospinning ...

Dielectric behavior in erbium-doped tellurite glass for potential high-energy capacitor

The use of erbium ions, Er3+ to enhance the dielectric properties is investigated in tellurite glass system for the first time, to the best of our knowledge. A glass series of tellurite glass with chemical composition, {[(TeO2)70(B2O3)30]70(ZnO)30}100−y(Er2O3)y (y = 0, 0.005, 0.01, 0.02, 0.03, 0.04 and 0.05) was fabricated via melt-quenched technique. The X-ray diffraction and Fourier transform infrared spectroscopy analysis proved the amorphous structure and the formation of nonbridging oxygen in the glass system. The Er3+ ions affect greatly to the dielectric constant, e′ in which the dielectric constant, e′ show high value at a lower frequency and higher temperature (above 110 °C). The reduction of dielectric constant, e′ is found with the increment value of frequency, which corresponds to the formation of the hindrance effect on heavy dipoles caused by the mixed transition-ion effect. Meanwhile, the dielectric constant, e′ is enhanced with the increase of temperature. The activation energy of the glass system is found to decrease, which is due to the high polarizability of Er3+ ions in the glass system. Based on these results, the erbium-doped tellurite glass is a potential kind of high-energy capacitor.

High Capacitive Energy Storage of Nest-Like Porous Graphene Microspheres Electrode with High Mass Loading.

Nest-like porous graphene microspheres (NPGMs) are grown by using a chemical vapor deposition (CVD) method in a fluidized bed reactor from methane and basic magnesium carbonate microspheres (synthesized by a stirring-induced crystallization approach) as carbon source and template, respectively. The CVD-derived NPGMs have a few-layer structure and high electrical conductivity, as well as a three-dimensional individual macroarchitecture accompanied with well-developed pore channels and great structural integrity. As the electrode for a symmetric supercapacitor, the effect of different mass loadings for NPGMs-based electrodes on the capacitive energy-storage performance is investigated. Superior electrochemical properties with respect to gravimetric, areal, and total capacitances, rate capability, and durability are shown by the NPGMs-based symmetric supercapacitors, even at mass loadings up to 10 mg cm-2 . Moreover, the electrochemical behavior of the NPGMs-based electrode is much superior to those of two-dimensional lamella-like graphene and commercial activated carbon.

High Energy Capacitors Based on All Metal-Organic Frameworks Derivatives and Solar-Charging Station Application.

High energy and efficient solar charging stations using electrochemical capacitors (ECs) are a promising portable power source for the future. In this work, two kinds of metal-organic framework (MOF) derivatives, NiO/Co3 O4 microcubes and Fe2 O3 microleaves, are prepared via thermal treatment and assembled into electrochemical capacitors, which deliver a relatively high specific energy density of 46 Wh kg-1 at 690 W kg-1 . In addition, a solar-charging power system consisting of the electrochemical capacitors and monocrystalline silicon plates is fabricated and a motor fan or 25 LEDs for 5 and 30 min, respectively, is powered. This work not only adds two novel materials to the growing categories of MOF-derived advanced materials, but also successfully achieves an efficient solar-ECs system for the first time based on all MOF derivatives, which has a certain reference for developing efficient solar-charge systems.

High energy and power lithium-ion capacitors based on Mn3O4/3D-graphene as anode and activated polyaniline-derived carbon nanorods as cathode

Recently, high performance energy storage devices are increasingly required in many new fields such as smartphone, pilotless automobile. Lithium-ion capacitors (LICs) have become the promising energy storage devices because of the higher power density, electrostatic capacity and long cycle life. Nevertheless, the limitation of the battery-type anode electrode and the capacitance-type cathode electrode with slow kinetics and low specific surface area leads to the LICs remaining lower energy density in high current density. In this report, a high performance LIC assembled by Mn3O4-graphene coupled with activated polyaniline-derived carbon (APDC) is firstly presented. Mn3O4-G composite material exhibits an outstanding invertible capacity of 489.8 mAh g−1 (at 1 A g−1) in a wide working window (0.01–3 V vs. Li/Li+) with an excellent coulombic efficiency in half cell, which is the highest capacitance reported for Mn3O4 so far. By utilization of Mn3O4-G composite as anode and APDC with the large surface of 1641.9 m2 g−1 as cathode, the assembled LIC of Mn3O4-G//APDC possesses an energy density of 97.2 Wh kg−1 at power density of 62.5 W kg−1, even at a relatively higher power density of 6250 W kg−1, its energy density can retain 5.0 Wh kg−1.

Temperature dependent dielectric and electric properties of zinc silicate nanorods

In this article, single crystalline pristine zinc silicate (Zn2SiO4) nanorods were grown by low temperature hydrothermal technique. The morphological and crystal structural analysis reveals the formation of nanostructures with nanorods shape and willemite structure of the α-Zn2SiO4 nanorods phase. Field emission-scanning electron microscope (FE-SEM) studies shows that length and radius of grown nanorods were in range of 1.5–2μm and 25–30 nm, respectively. Presence of various characteristic peaks in Zn2SiO4 nanorods were confirmed by Fourier transform-infrared spectroscopy (FT-IR) analysis. A very high dielectric constant of 222 was observed at room temperature and a sharp increase in the dielectric constant with an ultra-high dielectric constant of ∼19185 was observed at 100 °C. The variation of dielectric constant, loss and ac conductivity as a function of frequency was also studied. Temperature dependent (RT to 300 °C) dielectric constant, dissipation factor and ac conductivity were also investigated in the frequency range of 20 Hz–2MHz for the first time. It was observed that ac conductivity increased with increase of temperature up to 100 °C and then decreased. Such high dielectric and electric properties of Zn2SiO4 shows its great potential towards various nano-scale high energy capacitor and high-k dielectric nano-transistor applications.