Supercapacitor Cell Research Articles

Preparation of electrochemically stable choline chloride-sugar based sustainable electrolytes and study of effect of water on their electrochemical behaviour

In this work, Choline chloride-sugar (glucose, fructose, cane sugar) based sustainable electrolytes are prepared and effect of water on their electrochemical properties are analysed. The electrolytes are prepared by mixing the choline chloride and sugar and stirred on magnetic stirrer till a clear solution is obtained. The electrolytes are characterized using FTIR technique, cyclic voltammetry technique for electrochemical stability measurement and electrochemical impedance spectroscopy for ionic conductivity. The electrochemical stability window of electrolytes decreases from 1.8 V to 1.6 V and ionic conductivity increases on addition of water in electrolytes. The supercapacitor cells are fabricated using activated carbon as electrode material and prepared electrolytes. The supercapacitor cells are characterized using cyclic voltammetry and electrochemical impedance spectroscopy. The highest specific capacitance value of 1.34 F/g@5mV/s is observed for choline chloride-glucose electrolyte based supercapacitor. The bulk resistance measured using nyquist plot of cells also decreases on addition of water into electrolytes.

CARBON NANOFIBER COFFEE GROUNDS AS ANODE MATERIAL FOR LITHIUM BATTERIES – ION REVIEW

Development of lithium ion batteries (LIBs) from carbonaceous materials with the desired properties to be successfully obtained using a low-cost and environmentally friendly approach based on the dry grinding mechanism of used coffee grounds (SCG). Carbon nanofiber is a material made of carbon with a diameter of nano-sized and a length of micro-sized. Carbon Nanofiber (CNF), a type of carbon fiber vapor grown (VGCF), and a grown carbon fiber vapor (VGCNF) are nanostructures. Carbon nanofiber materials are considered promising electrodes for supercapacitor cells. In making nanofiber sheets using the electrospinning method, it must also be based on the parameters of the forming process to be applied as an anode to lithium-ion batteries. Carbon material derived from used coffee grounds is used as an anodic material that produces a special capacity with a current density. In addition, the material demonstrates competitive anode performance with reversible capacity and efficiency. So, this work contributes to the development of environmentally friendly batteries using low-cost materials as a promising solution to increase the demand for energy storage.

A durable high-energy implantable energy storage system with binder-free electrodes useable in body fluids

We developed a flexible supercapacitor cell with biocompatible oxidized SWCNTs driven by electrolytes in body fluids through integration with a wireless sensor network for use in implantable electronic medical devices (IEMDs).

슈퍼커패시터 전압 밸런싱을 위한 디지털 제어기 개발

In this paper, a digital controller is developed to perform voltage balancing of the supercapacitor cells. The bidirectional flyback converter which has a simple structure and is frequently used in charging and discharging circuits is used to charge and discharge the supercapacitor cells. The balancing circuit with the controller constructed in this paper uses the capacitor placed on the rectifier circuit of the input ac source to exchange energies among supercapacitor cells instead of auxiliary capacitors or batteries which are usually used in active shuttling battery cell balancing circuits. The validity of the controller developed for the supercapacitor voltage balancing is shown through experimental results.

Fe3O4/graphene-oxide/chitosan hybrid aerogel based high performance supercapacitor: effect of aqueous electrolytes on storage capacity & cell stability

In this work, Fe3O4/graphene-oxide/chitosan aerogel (GCFA) with 3-D interconnected structure (average pore size ∼8.4 nm) and moderate BET surface area (∼59 m2/g) is synthesized by hydrothermal route. Three different hybrid symmetric supercapacitor cells are fabricated using GCFA as active electrode material, using basic (6M KOH: cell-1), acidic (1M H2SO4: cell-2), & neutral (Na2SO4: cell-3) as electrolyte mediums. Subsequently, a comprehensive study is carried out to assess the effect of electrolyte on the porous architecture, charge storage capacity, rate capability and cyclic stability. Besides, cell-3 also shows good cyclic stability with low initial fading (∼15%), good capacity retention (∼84%) It has been observed that cell-3 displayed better performance (specific capacitance ∼160 F g−1, specific energy∼14.6 Wh kg−1 and specific power∼0.77 kW kg−1) than either of cell-2 (∼160 F g−1, ∼7.84 Wh kg−1 and ∼0.45 kW kg−1) or cell-1 (∼102 F g−1, ∼1.54 Wh kg−1 and ∼0.14 kW kg−1) and excellent coulombic efficiency (∼91%) even after 10,000 charge-discharge cycles. This is attributed to the better pore accessibility, stability of residual surface functionalities under potential cycling, and least screening for intra-pore shuttling of counter-ions under neutral medium.

Improvement of Stretchable and Washable Carbon‐Nanotube‐Based Textile Supercapacitors by using Molybdenum Trioxide Nanoflakes and Prewashing Treatment

AbstractThe attraction of electronic textiles for next‐generation wearable electronic devices has raised the demands of washable and stretchable energy storage. However, negative effects of washing on the textile‐based devices are majorly known. In this work, besides the innovation of a conventional stretchable composite based on carbon nanotubes (CNT) and polydimethylsiloxane (PDMS) for textile‐based supercapacitors, findings regarding negative and positive effects of washing are introduced. Since the CNT‐and‐PDMS‐based composite (CNT+PDMS) owns high stretchability but low electrochemical performance, two strategies using molybdenum trioxide (MoO3) nanoflakes are designed for upgrading the composite performance. Through stretching, washing, and electrochemical tests, the pros and cons of these strategies are revealed and discussed. Besides, a positive effect of chemical treatment of a liquid detergent (i.e., prewashing) is discovered, and it can improve the prewashed supercapacitor electrodes from 10 to 84 mF cm−2 at a scan rate of 10 mV s−1. Compared to supercapacitor cells assembled from unwashed electrodes, those of the sufficiently prewashed electrodes possess similar stretchability (≈60%) but threefold higher energy and power densities (3.9 μWh cm−2 and 0.89 mW cm−2, respectively). Overall, those findings are beneficial for the development of sustainable e‐textiles for wearable electronic applications.

Development of a Smart Supercapacitor Energy Storage System for Aircraft Electric Power Systems

This paper presents the development of a supercapacitor energy storage system (ESS) aimed to minimize weight, which is very important for aerospace applications, whilst integrating smart functionalities like voltage monitoring, equalization, and overvoltage protection for the cells. The methodology for selecting the supercapacitor cells type/size is detailed to achieve the safest and most energy-dense ESS. Additionally, the development of the interface electronics for cells’ voltage monitoring and overvoltage protection is presented. The proposed design implements a modular distributed architecture coordinated using communication buses to minimize the wirings and associated complexity and to enable system reconfiguration and expansions, as well as fault diagnoses. Validating the proposed ESS functionalities has been done via experimental testing and the results are presented and discussed.

The production of rGO/ RuO2 aerogel supercapacitor and analysis of its electrochemical performances

In this study, ruthenium was bonded to the reduced graphene oxide in an ultrasonic bath. The aerogel of the mixture was produced at −78 °C. Structural characterization of aerogels was done with XRD and FTIR, surface characterization was performed with STEM, and elemental analysis was conducted by EDX analysis. The produced aerogel composites were transformed into electrodes on conductive Nickel foam. IviumStat, a potentiostat/galvanostat device, was used for the electrochemical characterization of the symmetrical supercapacitors. According to CV voltammograms, rGO/RuO 2 aerogels' highest specific capacitance was calculated as 328.6 F g −1 at a potential scan rate of 5 mV s −1 . The assembled rGO/RuO 2 aerogel-based supercapacitor cell offered a high energy density value of 31.1 W h kg −1 even at the power density of 8.365 kW kg −1 ; this is comparable to that of lead-acid and nickel-metal hybrid batteries.

Structural supercapacitor constructed by SnO2/graphene coated nickel foam electrode and synchronously synthesized polymer cement electrolyte at room temperature

The design of high comprehensive properties structural supercapacitors requires advanced electrode materials with suitable porous structure for ion diffusion, as well as unique solid electrolyte owning excellent mechanical property under high-pressure compression. Herein, we presented a novel structural supercapacitor cell constructed by graphene-coated nickel foam decorated with SnO2 electrode and PAM–Portland cement electrolyte. It was found that the RGO/SnO2-1 electrode displays superior electrochemical performance with the highest areal capacitance of 0.374 F cm−2 at the current density of 1 mA cm−2, good cycle stability, and capacitance retention rate can reach 80.4% after 1000 cycles. Polymer-inorganic cement electrolyte was prepared by synchronous reaction at room temperature. The resulting structural supercapacitor cell showed relatively high electrochemical and mechanical properties. The areal capacitance was as high as 61.0 mF cm−2 at the current density of 0.1 mA cm−2. The excellent electrochemical performance combined with high mechanical comprehensive properties makes it a promising candidate in civil engineering applications.

The production of carbon electrodes from lignocellulosic biomass of areca midrib through a chemical activation process for supercapacitor cells application

ABSTRACT Lignocellulosic biomass can be used as a suitable basic material for producing activated carbon for use as a supercapacitor cell electrode, due to the high specific surface area, adjustable pore structure, chemical stability, electrical conductivity, and environmentally friendly. Lignocellulosic biomass of areca midrib (AM) is the first biomass to be used as a carbon electrode of a supercapacitor cell carbon without an adhesive material. AM is processed into self-adhesive carbon grains (SACG). Furthermore, SACG is chemically activated with potassium hydroxide (KOH) activator with varying concentrations 0.1 M, 0.2 M, and 0.3 M for get green monolith, before carbonization with N2 gas at 600°C and physical activation with CO2 gas at 700°C to produce carbon monolith electrodes for supercapacitor applications. X-ray diffraction and N2 isothermal methods to determine physical properties of carbon electrodes, while cyclic voltammetry method to determine electrochemical properties of supercapacitor cells. The results of the microstructure analysis showed the Areca carbon midrib electrode has a semicrystalline structure, indicated by the presence of (002) and (100) hkl planes at an angle of 2θ about 24° and 44°, while the highest heap height (Lc) value was produced at a concentration of 0.2 M (carbon electrodes AM-02). The results of isothermal gas N2 and electrochemical properties analysis show that carbon electrodes AM-02 have the highest specific surface area (SSA) and specific capacitance (Csp) of 654.729 m2/g and 142 F/g, respectively. Based on research results, it was shown that the AM-02 had a better potential as an energy storage device for supercapacitor applications than the AM-01 and AM-03 samples.

Mn(OH)2-containing Co(OH)2/Ni(OH)2 Core-shelled structure for ultrahigh energy density asymmetric supercapacitor

In this work, a facile hydrothermal method is used to grow ternary metal hydroxide nanorods on Ni foam for use as a novel electrode in pseudocapacitor. The nanorods exhibit a unique core-shelled structure that has an Mn(OH)2-containing Co(OH)2 core and a Ni(OH)2 shell. The resulting core–shell structured electrode shows an excellent specific capacitance (Csp), high retention, and great cycling stability up to 2000 cycles. The excellent electrochemical performance is ascribed to the unique synergistic effect of Co(OH)2, Mn(OH)2, and Ni(OH)2. The Csp is optimized to be 2286F g−1 with 0.9 mg of active mass. The Mn(OH)2-containing Co(OH)2/Ni(OH)2 core-shelled structure is also evaluated as an positive electrode in asymmetric supercapacitor cell with N-doped graphene as an negative electrode. The asymmetric supercapacitor cell exhibits an ultrahigh energy density of 92 Wh kg−1 at a power density of 1.7 kW kg−1. Furthermore, the asymmetric supercapacitor cell shows an excellent cycling stability with a capacitance retention of 91.7% over 5,000 cycles. The diffusion-controlled charge storage and surface-charge controlled storage mechanisms in the core and shell, respectively, lead to these outstanding electrochemical performances.

Fabrication of High-Performance Flexible Supercapacitor Electrodes with Poly(3,4-ethylenedioxythiophene) (PEDOT) Grown on Carbon-Deposited Polyurethane Sponge

Composite porous supercapacitor electrodes were prepared by growing poly(3,4-ethylenedioxythiophene) (PEDOT) on graphite nanoplatelet- or graphene nanoplatelet-deposited open-cell polyurethane (PU) sponges via a vapor phase polymerization (VPP) method. The resulting composite supercapacitor electrodes exhibited great capacitive performance, with PEDOT acting as both the conductive binder and the active material. The chemical composition was characterized by Raman spectroscopy and the surface morphology was characterized by scanning electron microscopy (SEM). Cyclic voltammetry (CV), charge-discharge (CD) tests and electrochemical impedance spectroscopy were utilized to study the electrical performance of the composite electrodes produced in symmetrically configured supercapacitor cells. The carbon material deposited on PU substrates and the polymerization temperature of PEDOT affected significantly the PEDOT morphology and the electrical properties of the resulting composite sponges. The highest areal specific capacitance 798.2 mF cm−2 was obtained with the composite sponge fabricated by VPP of PEDOT at 110 °C with graphene nanoplatelet-deposited PU sponge substrate. The capacitance retention of this composite electrode was 101.0% after 10,000 charging–discharging cycles. The high flexibility, high areal specific capacitance, excellent long-term cycling stability and low cost make these composite sponges promising electrode materials for supercapacitors.

In-situ design of porous vanadium nitride@carbon nanobelts: A promising material for high-performance asymmetric supercapacitors

Vanadium nitride and porous carbon are emerging as new class of electrodes and are extensively being explored as high-performance supercapacitor (SC) materials for their interesting properties. In this study, vanadium nitride@porous carbon (VN@C) nanostructured hybrid material for SCs is synthesized utilizing in-situ, one-pot chemical synthesis technique. The VN@C hybrid nanostructure has achieved very high capacitance by utilizing the combinations of electric double layer capacitive (EDLC) properties of porous carbon and pseudocapacitive characteristics of VN nanoparticles (VN NPs) and delivered maximum specific capacitance of 1850 C g−1 @10 A g−1 current density, with an excellent rate capability of 98% over 2000 cycles. Exploring the excellent electrochemical characteristics of VN@C, an asymmetric supercapacitor (ASC) cell is constructed with activated carbon (AC) as negative and VN@C as positive electrode. Remarkably, the as-constructed VN@C//AC ASC device achieves an excellent capacitance of 102 F g−1 at 1 A g−1 with the energy and power densities of 17–30 Wh kg−1 and 701–5608 W kg−1, respectively, over the current density range of 1–8 A g−1. Our facile preparation of highly porous carbon nanobelt-vanadium nitride composite along with high-energy storage properties pave the way for the development of various carbon–metal nitride hybrid nanostructures for promising energy storage applications.

Fabrication of various metal hexacyanoferrates@CNF through acid-regulation for high-performance supercapacitor with superior stability

Prussian blue analogs, as a pseudo-capacitor electrode materials hold great potential due to their unique framework structure, excellent electrochemical activity and high specific capacity. Herein, a versatile method for the growth of series of metal hexacyanoferrates (MHCF) on carbon nanofiber with high conductivity and flexibility was proposed. By controlling the releasing rate of metal ions through acid modulation of solution, the series of MHCF nanocubes were successfully embedded on the carbon nanofibers with super stability. Different MHCF presented various loading density. Among the MHCFs, nickel hexacyanoferrate (NiHCF) is the most easily formed with high density and uniform distribution. The obtained self-supporting NiHCF@CNF, as a representative electrode, exhibited high specific capacitance (507 F g−1, 1 A g−1) and remarkable rate performance (67% retention at 10 A g−1). Moreover, the NiHCF@CNF-based hybrid supercapacitor cell delivered a high energy density of 60 Wh kg−1 at the power density of 810 W kg−1. Meanwhile, the capacitor showed extremely high stability due to tight anchoring of NiHCF on CNFs. This work provides a simple and versatile method to produce self-supporting MHCF@CNF composites for constructing high performance supercapacitor.

High efficient carbon coated TiO2 electrode for ultra-capacitor applications

The present paper reports the investigation of structural, optical, chemical bonding, and electrical properties of the carbon black (CB)/TiO2 composite synthesized via the standard sol–gel method. The structural and morphological properties have been investigated using x-ray diffraction and also field emission scanning electron microscopy to confirm the formation of the nanocomposite. The electrochemical performance of the two-electrode symmetric fabricated supercapacitor (SC) has been examined by complex impedance spectroscopy, cyclic voltammetry, and galvanostatic charge–discharge (GCD). The electrode CT15 (15% TiO2 in CB matrix) shows a high specific capacitance of 236 F g−1 at scan rate 10 mV s−1. The GCD illustrates good specific capacitance retention of 90.3% after 10 000 cycles and with energy density and power density values as 22 Wh kg−1 and 625 kW kg−1 respectively (at 1 A g−1) in the voltage window of 1.2 V. The CT15 electrode cell demonstrates superior electrochemical performance as compared to other electrodes. Electrochemical impedance spectroscopy (EIS) demonstrates the capacitive behaviour of the composite electrode with a low value of resistance. The SC cell having optimum performance has been chosen to demonstrate the glowing red light emitting diode. A mechanism has also been proposed based on received data parameters to validate the SC performance.

Used carbon water filter—A source for high performance microporous activated carbon electrode for aqueous supercapacitor

The development of high-performance energy storage systems will address the pollution and energy demand problems. The main component in the presently available supercapacitor device is carbon. However, supercapacitor grade carbon availability, cost, and energy density problems must be addressed in the carbon-based system. In this work, readily available, reusable, and cheaper carbon collected from the used carbon water filter and its heat-treated, chemically activated carbons are used as electroactive materials. The carbon is amorphous, microporous, thermally stable up to 510 °C, having a high specific surface area, carbon-chain contains carbonyl group. This carbon in symmetric supercapacitor shows both behaviors of electrochemical double-layer capacitor and pseudocapacitor. Specific capacitance value (F g−1) increases in the order carbon (165) < calcinated carbon (191) < chemically treated carbon (252) at 1 A g−1. The cell shows a retention capacitance of 98% at 10,000 cycles at 2 A g−1. Even at a higher current density of 5 A g−1, gives 87% retention at 15,000. Cell also shows good rate capability, Ragone plot behavior, phase angle (84°). Three cells connected in a series glow LED bulb. Thus, this reusable carbon could be considered an efficient electrode in an aqueous-based supercapacitor cell for commercial applications.

Hybrid Energy Storage System with Vehicle Body Integrated Super-Capacitor and Li-Ion Battery: Model, Design and Implementation, for Distributed Energy Storage

In this paper, a distributed energy storage design within an electric vehicle for smarter mobility applications is introduced. Idea of body integrated super-capacitor technology, design concept and its implementation is proposed in the paper. Individual super-capacitor cells are connected in series or parallel to form a string connection of super-capacitors with the associated management unit to form a panel. These super-capacitor panels are shaped to fit the alternative concept of vehicle design, and it solves the design issues and prepares for configurable electric vehicles. Body integration of super-capacitors enhances the acceleration, and regenerative braking performances of the electric vehicle increases the operating life of the Li-ion battery and improves space utilization by giving more area for the main energy source, the Li-ion battery. Integrating super-capacitor into the car body involves special packaging technology to minimize space and promotes distributed energy storage within a vehicle. This pioneering design encourages future configurable electric vehicles. Model of both the Li-ion battery and the super-capacitor employed is studied with its series internal resistance determined at various C-rates. Loss and the efficiency analysis of the bi-directional converter, traits of body integrated super-capacitors system and control of the interleaved bi-directional converter to regulate the power-sharing in the hybrid energy storage system is presented.

Activated Carbons (AC) Prepared by Direct CO2 Activation of Parsea Americana seeds Biomass for Supercapacitor Electrodes

Biomass converted into activated carbon (AC) by using physical activation method can form micro-meso pore structure and maintain the interconnected natural pore network of biomass. AC is prepared from the biomass of Parsea Americana seeds (PAS) through a process of pre-carbonization, chemical activation, carbonization and physical activation which is activated at temperatures of 700°C, 800°C, and 900°C. Characterization of physical properties of AC electrodes consisted of X-ray diffraction, Scanning Electron Microscope-Energy Dispersive X-ray and characterization of electrochemical properties of supercapacitor cells using Cyclic Voltametry. The results showed that the microstructure of the AC electrode has a semicrystalline structure characterized by the presence of two sloping peaks at an angle of 2θ around 24° and 44° which corresponded to the hkl (002) and (100) planes, where the lowest Lc value was produced by the PAS-900 sample. The PAS-900 sample had aggregates or lumps with smaller size in small amounts in the presence of micro-mesopores and had the highest carbon content of 94.50% with the highest capacitance value of 203.12 F/g. The temperature of 900°C is the best activation temperature in the process of manufacture AC electrodes from Parsea Americana seeds biomass for supercapacitor cell applications.

Green synthesis of Supercapacitor electrodes activated carbon from Veitchia Merilli Seed waste by a two-stages pyrolysis in integration

Pyrolysis process consists of two-stages in integration aims to carbon purification, evaporates volatile compounds so that it enlarges the pore diameter, and increases the surface area of the activated carbon. This research was used Veitchia Merilli seed (VMS) waste by optimizing the stages-carbonization to obtain a high specific capacitance. Initial preparation begins with the pre-carbonization process at a temperature of 200°C, the activated carbon powder is converted into a monolith form using a Hydraulic Press and followed by a pyrolysis process in the stages-carbonization with temperature variations of 500°C, 600°C, and 700°C and the stages-physical activation at temperature of 800°C. The results showed that the thermal resistance temperature of the carbon powder was 287°C. The lowest density value occurs in the VMS-600 sample of 0.591 gr/cm3 and Microstructure analysis shows that the carbon electrode is amorphous which is characterized by the presence of peaks at 2θ angles around 24° and 44° with the highest Lc value of 15.069 nm, with the highest specific capacitance value of the supercapacitor cell of 210,442 F/g. Temperature 600°C is the optimum temperature carbonization in the process fabrication of carbon electrodes from VMS waste for supercapacitor cell application.

Fabrication of Carbon Electrodes from Sago Midrib Biomass with Chemical Variation for Supercapacitor Cell Application

Activated carbon with high porosity and controlled pores structure are widely applied as supercapacitor electrodes biomass derived from sago midrib (PS). Activated carbon based on sago midrib without chemical agent and using chemical agent ZnCl2 and NaOH by a concentration 0,5 M has been fabricated with a purpose to produce distribution of mesopores and micropores. Samples were carbonized at temperature 600°C using N2 gas followed by a physical activation process using CO2 gas at temperature of 700°C. The highest mass loss percentage of carbon electrode PS-ZnCl2 was 51,6% Microstructure analysis shows that amorphous structure for the activated carbon electrodes is shown by the presence of the peaks of 2θ around 240 and 440 with the highest Lc presented by ZnCl2. SEM characterization showed the domination of mesopores and a few of micropores presented by ZnCl2. EDX characterization showed the highest atomic carbon percentage is 90,27%. Specific capacitance was determined by cyclic voltammetry method and found the highest in PS-ZnCl2 was 138 F/g. The result from the physical and chemical properties, ZnCl2 is the best chemical agent from biomass-derived sago midrib for the best performance of supercapacitor cells.