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Specific surface area and electrical conductivity are two decisive factors affecting materials properties. As a potential energy material, MoO 3 is still limited in research and application due to its inherent defects. Ag nanoparticles with good electrical conductivity and unique small-size effect are predicted to have more hopeful prospects in energy storage. Ag@MoO 3 composites with different Ag content were successfully prepared by a simple liquid-phase reduction method. The results show that the Ag@MoO 3 composite has good morphology and the maximum capacitance (225 F/g) when the content of Ag is 8%. Notably, the internal resistance and Warberg resistance of the composite compared with that of MoO 3 have been greatly reduced. It is mainly due to the high ion conductivity and small-size effect of Ag nanoparticles, which effectively improve the diffusion efficiency of ions between electrolyte and active materials. Practical application feasibility of Ag@MoO 3 electrode was tested in the two-electrode system. Symmetrical coin cell supercapacitor using 8% Ag@MoO 3 as electrodes has superior performance. Our work has potential reference value for the combination and characterization of energy storage materials. [ABSTRACT FROM AUTHOR]

Non-metal-based compounds have emerged as promising electrodes in recent years to replace scarce and expensive transition-metals for energy storage applications. Herein, a simple electro-spinning technique followed by carbonization is used to create tetraphosphorus triselenide (P 4 Se 3) nano-flakes encapsulated in carbon nanofiber (P 4 Se 3 @CNF) to obtain a binder-free, metal-free and flexible hybrid electrode with high electrical conductivity and cyclic stability. A remarkable capacitive performance (5.5-folds@P 4 Se 3) of 810 F g-1/112.5 mAhg−1@0.9 A g-1 has been obtained using P 4 Se 3 @CNF electrode with an excellent rate capability compared to pristine (P 4 Se 3) which is further supported by theoretical calculations via intercalating graphene within bare P 4 Se 3 flakes inducing partial charge redistribution in hetero-structure. A flexible pouch-type hybrid-supercapacitor followed by coin-cell has been manufactured offering exceptional energy density without sacrificing power density and ultra-long durability over 35,000 and 1,00,000-cycles with capacitance-retention of 99.77 % and 100 %, respectively. It has been demonstrated that as-fabricated device has practical usefulness towards renewable energy harvesting and storage via integrating commercial solar cell module with supercapattery array that can enlighten the blue LED approximately for 31 min, rotate the homemade windmill device, power Arduino and glow "INST" against 2 min of charging. This work demonstrates a facile route towards the development of metal-free electrochemical renewable energy storage/transfer devices offering an inevitable adoption in industrial platforms. Efficient renewable energy harvesting and storage are achieved through the integration of a commercial solar cell module with a non-metal-based supercapattery array (two coin cells in series). This configuration powers a red LED for an impressive 30 min after just 2 min of charging. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Green synthesis of α-V 2 O 5 nanosheets using Aloe Vera leaf extract. • Electrochemical phase transformation of α-V 2 O 5 to NaV 3 O 8 nanosheets. • Structural and morphological evolutions during electrochemical phase transformation. • Specific capacitance of 640.10 F g−1 at 0.5 A g−1 NaV 3 O 8 nanosheets electrode. Nowadays, cost-effective and environmentally friendly supercapacitors (SCs) with high energy and power densities are gaining significant research attention since they could broaden the application of capacitors. The present study demonstrates a low-cost green synthesis technique to prepare the α-V 2 O 5 phase using Aloe Vera leaf extract. X-ray diffraction technique confirmed the formation of the orthorhombic α-V 2 O 5 phase. The prepared α-V 2 O 5 was employed as an electrode material for SC application. During an electrochemical cyclic voltammetry test in Na 2 SO 4 electrolyte, Na+ ions intercalation and de-intercalation processes resulted in a phase transformation of α-V 2 O 5 to NaV 3 O 8. Structural transformation (i.e., orthorhombic to monoclinic crystal structure) and morphological changes were also observed during the electrochemical phase conversion process. This electrochemical phase transformation process improved the overall supercapacitive performance of the α-V 2 O 5 material. Such electrochemically converted NaV 3 O 8 displayed a maximum specific capacitance of 640.1 F g−1 at 0.5 A g−1 with a long cyclic stability. Furthermore, the AC // NaV 3 O 8 asymmetric SC coin cell device delivered a maximum energy density of 62.6 Wh kg−1 and a power density of 7.3 kW kg−1 along with an excellent cycling stability of ∼81 % over 5000 GCD cycles. [ABSTRACT FROM AUTHOR]

Research on the thermal behavior of Li-ion batteries fosters the understanding of heat generating effects and the dimensioning of battery thermal management systems (TMS). First comprehensive studies with a new DSC-like calorimeter for coin-cells are performed to determine thermal properties of a LiCoO 2 -graphite cell. The high precision and accuracy of the measurements are obtained by calibrating the signals using melting point standards in properly prepared coin-cell cases. The heat flow is measured during cycling with different C-rates between 0.23 C and 0.9 C under isothermal conditions at temperatures between 30 °C and 50 °C in steps of 5 K. Chemical and physical changes are identified in the measured heat flow signal and are discussed taking into account phase diagram information. Energetic efficiencies are calculated in dependence of temperature and C-rates by integrating the measured electrical power and heat values. The influence of cell aging on heat generation and usable capacity under operating conditions is shown. Considering the measured heat generation in a wide temperature range at different C-rates will make a valuable contribution to the understanding of material properties. This fundamental data is essential to improve thermal models to simulate spatially resolved heat dissipation in the electrodes to prevent over-heating. [ABSTRACT FROM AUTHOR]

• Synthesis of V 2 O 5 via simple thermal decomposition of ammonium metavanadate and glycine. • More than two fold increase in specific capacitance under light for V 2 O 5 ||AC device. • V 2 O 5 ||V 2 O 5 device was charged under light to 200 mV in 1 h. • Outstanding coulombic efficiency of 98% even after 40,000 cycles at a high current density of 10 and 15 mA cm−2. A photo-assisted energy storage system enables a new pathway to utilize unlimited solar energy. Herein, V 2 O 5 was synthesized using a simple, time-saving thermal decomposition process. The V 2 O 5 samples were characterized thoroughly. The photo-electrochemical performances of the as-prepared V 2 O 5 samples were evaluated using a three-electrode system. The material showed increased specific capacity from 45 C g−1 to 69 C g−1 in the presence of light. The photo-assisted V 2 O 5 ||V 2 O 5 and V 2 O 5 ||AC (activated carbon) ASC (asymetric supercapacitors) FTO devices effectively responded to the light sources. The areal capacity of the V 2 O 5 ||AC ASC FTO photo-assisted charging device was 112 mC cm−2 under the given light intensity, whereas the device tested using the conventional process (without light irradiation) delivered only 45 mC cm−2 at the same current density. Further, the asymmetric FTO device delivered high specific energy and power density of 9.8 Wh kg−1, and 29 W kg−1 respectively, in the presence of light. Notably, the symmetric FTO device was photo charged to 200 mV in 1 h without any external current and was discharged in the dark at 0.01 mA cm−2. On the other hand, V 2 O 5 symmetric coin cell delivered excellent cycle stability over 40,000 cycles at different current rates with an outstanding coulombic efficiency of 98%. These results are a clear indication that the photo charging-based supercapacitor will pave an innovative path in constructing futuristic energy storage devices. [ABSTRACT FROM AUTHOR]

This paper introduces a binder–free electrode prepared by a facile deposition of C/TiO 2 (Carbon/TiO 2 ) or C/GTiO 2 (Carbon/Graphene–TiO 2 ) on the coin cell anode using poly (methyl methacrylate) (PMMA) as a cheap carbon and binding source without using binders and a current collector. The use of graphene not only presents a conducting support to TiO 2 particles, but also greatly improves the porosity of the electrode relative to pristine TiO 2 or C/TiO 2 . In the lithium–ion battery (LIB) anode, the direct deposition enabled sufficient electrical conductivity of the electrode, the intercalated layer–by–layer (LBL) arrangement of the C/GTiO 2 allowed sufficient Li + accessibility, and the resulting electrode exhibited a higher specific capacity and an excellent rate capability compared to conventional TiO 2 electrodes. Drop testing of the binder–free cells prior to electrochemical testing showed that all cells retained their original specific capacity, rate capability, and cycle stability, thus confirming the strong binding of the binder–free electrodes on the coin cell surface. [ABSTRACT FROM AUTHOR]

[Display omitted] • Binder-free Cr/NiO electrodes prepared by single-step magnetron sputtering. • Synergistic effect of Cr in NiO is highlighted in asymmetric supercapacitor. • Cr doped NiO showed an excellent supercapacitive performance (429 mF cm−2). • Remarkable cycling stability performance over 5,000 cycles. • Aging effect of coin cell was examined after 720 h. • Cr/NiO electrodes can utilized for portable and miniaturized electronic devices. Recently, metal oxides (MOs) have received tremendous interest for flexible energy storage systems: in particular, supercapacitors (SCs). SC electrodes are commonly fabricated via the coating of MOs particles, conductive carbon and binders. However, such electrodes, can weaken the performance of SCs. In this work, binder-free nanocluster Cr-doped NiO thin films are grown on flexible stainless-steel (SS) foils using a one-step co-sputtering technique. The distinctive nanocluster structure of Cr-incorporated NiO thin film electrodes (TFEs) has the benefit of reduced ion diffusion length and good charge transport, and can increase the accessibility of ions onto the active surface area. The developed TFEs are examined in 2 M KOH aqueous electrolyte, demonstrating highest areal capacitance of 429 mF cm−2 (251 mC cm−2). Subsequently, an asymmetric coin cell (ACC) SC is assembled. Even after 5,000 cycles, the developed ACC SC demonstrates exceptional cycling stability. Thereafter, the aging test is conducted after 720 h and reveals good electrochemical performance with minimal capacitance fading. Results reveal that Cr-doped NiO TFEs show excellent electrochemical performance with higher areal capacitance and stability compared to NiO and other metal oxide-based TFEs reported previously. The grown Cr-doped NiO binder-free TFEs are good candidates for high-performance and flexible energy storage systems. [ABSTRACT FROM AUTHOR]

• Synthesis of silver-doped reduced graphene oxide/Pani composite. • Electrochemical measurements of silver-doped reduced graphene oxide/Pani composite. • Supercapacitor analysis of silver-doped reduced graphene oxide/Pani composite and coin cell application. In this study, graphene oxide was synthesized by the Hummers method. Reduced graphene oxide was obtained by the hydrothermal method. Then, silver-doped Reduced Graphene Oxide/Polyaniline (Ag-doped rGO/PANI) composites were synthesized. Some physical analyzes of the synthesized composite materials were made. In the XRD examination, it was understood that the materials generally have polyaniline properties. Electrochemical properties were investigated with electrodes prepared from these composites. Specific capacitance, energy, and power density values were calculated from these measurements. The specific capacitance was measured in the range of 0.5–30 A/g and the highest capacitance value was found to be 379 F/g. From these results, the material containing approximately 17 mass percent silver doped reduced graphene oxide gave better results among composite materials. This composite was the most stable material with results of 286–317 F/g at all applied currents. In addition, a coin cell application was made for this example and its measurements were taken. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Stainless-steel (SS) coin-cell parts are more vulnerable to corrosion than the Al. • SS degradation can accelerate the corrosion of Al current collectors. • Galvanic electron transfer from Al to SS can corrode the Al metal. • MD simulations verify SS and Al's corrosion mechanisms in the imide electrolyte. • SS and Al-free pouch cells with carbon current collector show improved cyclability. F-containing functional electrolytes have been extensively investigated to improve the performance of Li-metal batteries as they generate stable LiF-based solid–electrolyte interphase layers, improving Li deposition/dissolution efficiency. However, these imide-based electrolytes corrode not only the Al current collector but also the stainless steel (SS) component of the coin cell at high operating voltages. Additionally, deciding upon which part of the corrosion has a greater effect on the performance degradation remains a topic of debate. In this study, through systematic cell design exposing SS to LiFSI-based electrolyte, it is found that SS corrosion is a more dominant cause of capacity fading than the Al case. Moreover, the computational study reveals that the electron transfer from Al to SS decomposes FSI– and the resulting byproducts finally corrode Al. To develop stable cells by removing corrosion factors, the SS and Al-free pouch-type cells are proposed by integrating carbon current collectors and locally high-concentration electrolyte and exhibit 430 cycles with a coulombic efficiency of 99.93%. This study demonstrates the importance of careful selection of cell components and systematic cell design to ensure a robust interface at the cathode side, suggesting the necessity to develop a new testing cell to replace the current coin-cell platform. [ABSTRACT FROM AUTHOR]

Layered two-dimensional (2D) materials such as transition metal dichalcogenides (TMDCs) are receiving increased interest for applications in energy storage due to their high specific surface area and versatile electronic structure. In this work, we prepare solvent stabilised dispersions of a variety of few-layer thick TMDC crystals (MoS 2 , MoSe 2 , WS 2 , and TiS 2 ) by ultrasonication. The exfoliated materials were first characterised by a variety of techniques to determine their quality. These dispersions were then used to form supercapacitor electrodes by filtration, without use of any further conductive additives or polymeric binders. These thin layer TMDC electrodes were assembled into symmetrical coin-cell devices for comparative electrochemical testing. It was found that despite being the most widely studied material, MoS 2 suffers from inferior charge storage properties compared to the much higher conductivity and lower density TiS 2 . Impedance spectroscopy was used to investigate the charge storage mechanisms inside the coin cells, which were found to consist of a combination of both rapid, but low magnitude, electric double layer capacitance and much slower, but higher magnitude, ion adsorption pseudocapacitance. [ABSTRACT FROM AUTHOR]

• The power density decreases with increasing cathode diameter for the button cells. • Because the polarization resistances associated with gas diffusion process increases. • The polarization resistance also increases with increasing fuel utilization. • The power density is low for large-scale cells under high fuel utilization. Small-scale planar solid oxide fuel cells (SOFCs) with several centimeters in diameter called "button cells" or "coin cells" are widely used for fundamental research. Although the performance of large-scale cells is inferior to that of button cells, the precise reason is unclear. In the present work, electrochemical impedance spectroscopy (EIS) are performed for button cells with different cathode areas under different fuel utilization, and distribution of relaxation times analysis was conducted to deconvolute the EIS. The power density decreased with increasing cathode diameter for the button cells. The polarization resistances associated with the gas diffusion process at low frequencies increased for a cell with a large cathode area, when the gas flow path is different between the inner and outer electrode areas for the button cells. The polarization resistance related to the gas diffusion process also increases with increasing fuel utilization. As a result of simple simulation considering the Nernst loss, the power density at 0.75 V was estimated to be 0.169 W/cm2 at U f = 0.8 for a large-scall cell with dimensions of 10 × 10 cm2, which is smaller than that for a button cell with a cathode diameter of 6 mm (0.730 W/cm2 at U f = 0.04). [Display omitted] [ABSTRACT FROM AUTHOR]

Aqueous Zinc-batteries comprising organic cathode materials represent interesting candidates for sustainable, safe, environmentally friendly, and highly flexible secondary energy storage system. Here, we demonstrate that such an oxygen-tolerant, semi-organic setup can conveniently be prepared in an all-aqueous process, including all steps from the initial polymerization to the coin cell assembly without the need of any intermediate purification steps, and still reach high energy densities of 2.55 mAh cm−2. The TEMPO-modified and crosslinked poly(methacrylamide) cathode facilitates an excellent compatibility to the aqueous electrolyte and an efficient accessibility of the redox-active species due to the increased polarity of the material compared to the common poly(TEMPO-methacrylate) (PTMA). The material exhibits excellent stability (capacity retention of >99% after 1000 cycles at 5C) with low self-discharge and features high rate capabilities. The casting process from the aqueous slurry further appeared to be suitable for the preparation of ultra-thick but still homogeneous binder-free electrodes and exhibit total device capacities of approximately 4.5 mAh in a 2032-type coin cell. Since the overall process avoids harsh conditions or harmful solvents, is scalable, and relies on straightforward processing steps, it represents a promising step towards cost-effective and efficient rechargeable Zinc-based semi-organic batteries with competing capacities if further optimized. [Display omitted] • New poly (TEMPO-methacrylamide) polymer synthesized. • Obtainable through all-aqueous one-pot process. • Enables aqueous semi-organic coin cells with zinc anodes. • Stable long-term cycling at 1.5 V battery voltage. • High-capacity coin cells from ultra-thick electrodes. [ABSTRACT FROM AUTHOR]

In this study, a novel integrated two-in-one flexible micro sensors are fabricated using the micro-electro-mechanical systems (MEMS) process for in-situ monitoring of temperature and voltage in a coin cell. Temperatures fluctuate in a coin cell, as evidenced by the inner temperature changing more rapidly than the outer one. Additionally, monitoring the inner temperature is faster than the outer one. Charging and discharging causes non-uniform distributions of the inner voltage. [ABSTRACT FROM AUTHOR]

Abstract: To enhance the stability of potassium ferrate (VI) (K2FeO4) electrodes and their discharge capabilities in alkaline battery systems, yttria (Y2O3) doped zirconia (ZrO2) (denoted as Y2O3–ZrO2) coatings are utilized to protect the K2FeO4 electrode in alkaline electrolytes. The preparation conditions of Y2O3–ZrO2 coatings on K2FeO4 electrodes are investigated in detail and the optimum preparation conditions are determined. Results of discharge tests with open module batteries show that the Y2O3–ZrO2 coated K2FeO4 electrode (prepared under the optimum conditions) provides a superior discharge specific capacity than uncoated and ZrO2 coated K2FeO4 electrodes. Alternatively, to further explore the practical application of K2FeO4 electrodes, super-iron coin cells are assembled using a Y2O3–ZrO2 coated K2FeO4 electrode as the cathode and zinc foil as the anode. The discharge specific capacity and discharge specific energy of the coin cell with Y2O3–ZrO2 coated K2FeO4 cathode are 169.8mAhg−1 and 201.9Whkg−1 respectively, which are superior to the MnO2 coin cell. Therefore, the results indicate that Y2O3–ZrO2 coated K2FeO4 cathode is suitable for practical applications in alkaline battery systems. Consequently, the alkaline super-iron battery is expected to become a novel energy resource system that replaces present primary batteries in various electronic devices. [Copyright &y& Elsevier]

Abstract: Three classes of molecules have been shown to be successful for protecting lithium-ion cells during overcharge. These three classes are, the molecule 2,5-di-tert-butyl-1,4-dimethoxybenzene (DDB), molecules based on a phenothiazine core, such as 10-methylphenothiazine (MPT) and molecules based on a 2,2,6,6-tetramethylpiperidinyl-oxide (TEMPO) core, such as TEMPO and 4-cyano-TEMPO. These molecules were examined using Li-ion coin cells, three-electrode cyclic voltammetry and four-electrode cyclic voltammetry. Three-electrode cyclic voltammetry was used to measure the diffusion coefficients and the stability of the shuttle molecules at high and low potentials. The transport of electrons through the solid-electrolyte interface on the negative electrode to the oxidized shuttle molecule was studied using the four-electrode cell for electrolytes containing both LiPF6 and lithium bis(oxalato)borate salts. The rate of charge transfer to the oxidized TEMPO and MPT molecules is significantly reduced on glassy carbon below 1.7V (versus Li/Li+) in electrolytes containing LiBOB, but not in electrolytes containing LiPF6. Charge transfer to oxidized DDB seems facile at all potentials above 0.2V in both LiPF6 and LiBOB electrolytes. [Copyright &y& Elsevier]

[Display omitted] • Bismuth manganese oxide nanoflakes are synthesised by one step hydrothermal method. • Kinetics of charge transfer was explained using different techniques. • The diffusion and capacitive controlled contribution are differentiatedon the basis of CV data. • Coin cell device is fabricated for good performance practical application. Binary metal oxides are deposited via simple chemical routes for high-performance energy storage applications. In this work, we developed nanostructures of BiMnO 3 on Ni foam using a hydrothermal method. Initially, the (0 1 0) and (1 1 0) planes confirmed the presence of the BiMnO 3 phase. Snow fungus-like nanostructure was transferred to porous interconnected nanoflakes with an increase in deposition time. These nanoflakes serve as large active sites that are beneficial for the diffusion of electrolytic ions that enhance the charge storage and transport process. Consequently, the two-dimensional interconnected nanoflakes showed a high diffusion coefficient, standard rate constant, and minimum transfer coefficient. In addition, BiMnO 3 exhibited an aerial capacitance of 6000 mF cm−2 (1500 Fg−1) with an energy density of 102 Wh kg−1 at an applied current density of 20 mA cm−2. For practical applications, an asymmetric coin cell (ACC) device was assembled using BiMnO 3 as the positive electrode and activated carbon as the negative electrode in 3 M aqueous KOH as an electrolyte. The fabricated ACC device had an energy density of 14.4 Wh kg−1 at a power density of 50 W kg−1 with a 1.2 V potential; the capacitive retention was 90 %, with 97 % Coulombic efficiency up to 5000 cycles. Accordingly, the results determined that BiMnO 3 can be used as an electrode material for high-performance energy storage applications. [ABSTRACT FROM AUTHOR]

• Discarded lithium coin cells evaluated as a source of Li and Mn. • Enhancement of Mn dissolution in citric acid via thermal treatment. • Activation energy for the carbothermal reduction was found as 20.96 kJ/mol. • Lithium is recovered in the form of lithium carbonate. • The process developed is short, effective, and adaptable. Lithium-metal primary batteries, widely used in portable electronics, contain lithium, manganese, and carbon, which can be recycled to conserve resources and prevent environmental damage. This study investigates the thermal response of active material under ambient conditions and its effects on manganese dissolution in organic acid. Thus, spent lithium metal batteries were manually dismantled, the lithium they contain was dissolved in a mixture of distilled water and isobutyl alcohol, and the steel and active cathode material were mechanically separated. The thermal exposure of active material comprising MnO 2 and C resulted in carbothermal reduction with products Mn 3 O 4 and MnO. The composition of product at optimum condition (800 °C, 30 min) comprises 60 wt% Mn, 21.5 wt% O, and 18.5 wt% C in the form of MnO, Mn 3 O 4 , and C. Manganese extraction increased significantly on thermal treatment, yielding 81% at optimum condition. Therefore, thermal treatment for the indigenous reduction of MnO 2 , followed by leaching in an organic acid, is proposed for lithium and manganese value recovery from spent coin cells. The activation energy for thermal dissociation of active material has been identified as 20.96 kJ/ mol, and mass balance for the process followed has also been investigated. [ABSTRACT FROM AUTHOR]

• Easily synthesizable low-cost electro-active material of novel quinone derivative. • Optimized values for the electrode are 1.0 V, 1180 F g−1 at 9.5 A g−1, 10000 cycles. • Increased in performance by 6 e− transfer and incorporating high amount of quinone. • Cell having high in rate capability, cycle stability, energy and power density. The development of electrode materials for supercapacitors is a necessary research and development work to address the present-day energy crises. The improvement of productive pseudo-capacitors requires quick and reversible kinetics of redox-molecules. In the development of pseudo-capacitors, quinone/hydroquinone redox couples are one of the promising molecules. Graphite sheet, along with quinone molecules with an increased number of carbonyl groups, is expected to give higher performance hybrid supercapacitors. In this direction, a simple one-step reaction of p-benzoquinone and dopamine hydrochloride to 2,5-bis((3,4-dihydroxyphenethyl)amino)cyclohexa-2,5-diene-1,4-dione molecule (BQ-DP) is carried and confirmed the formation from Fourier-transform infrared, high-resolution mass, proton and carbon nuclear magnetic resonance spectra. This molecule is used as a redox system along with a graphite sheet as active electrode material for supercapacitor, wherein a redox system consists of three quinone groups with six electrons transfer reaction. Cyclic voltammetry and charge-discharge graphs, and two constant phase elements obtained from EIS measurement clearly show the contribution of both electrochemical double layer and pseudo-capacitor components. Both benzoquinone and dopamine groups are involved in the redox reaction. The values of specific capacitance for this electrode are 910 F g−1 at 5 mV s−1 and 1180 F g−1 at 9.5 A g−1, respectively. This cell is subjected to 10,000 charge-discharge cycles, which underwent decay in specific capacitance from 416 to 209 F g−1 up to 1000 cycles and then remains constant up to 7000 cycles. In the case of a negligible contribution of EDLC, the supercapacitor cell could be treated as a battery cell. The battery gives an initial specific capacity of 115–58 mAh g−1 at 1000 cycles. This quinone molecule showed higher electrochemical performance compared to the earlier reports on quinone molecules for supercapacitors. An alternative strategy to increase the performance of the quinone-graphite electrode is made by making holes on graphite sheet and accommodated more amount of electro-active quinone molecule and used as an electrode in symmetric cell configuration in coin cell and subjected for 5000 cycles in the voltage range from 0 to 1 V at 9.5 F g−1. The value of specific capacitance for the symmetric cell obtained from charge-discharge measurement for the electrode (419 F g−1) is found to be higher than that of the electrode without holes (324 F g−1). Redox system of quinone having capability of six electron transfer was synthesized easily as a high-performance electrode for supercapacitor with high energy density, high power density and longer cycle life. Image, graphical abstract [ABSTRACT FROM AUTHOR]

A novel ternary composite of carbon nanofibers/polyaniline‑manganese oxide (CNFs/PANI-MnO 2) was synthesized via electrospinning, carbonization followed by electrodeposition of PANI-MnO 2. The CNFs/PANI-MnO 2 composite exhibited excellent specific capacitance of 937.66 F/g at a scan rate of 5 mV/s and good cyclic stability with capacitance retention of 97.6% after 5000 consecutive cycles. The composite also exhibited superior performance with a specific energy of 66.12 Wh/kg at a specific power of 470.81 W/kg with low charge transfer resistance, R ct (1.81 Ω) and equivalent series resistance (32.18 Ω) indicating high electronic conductivity. Three symmetrical CNFs/PANI-MnO 2 composites assembled in series using coin cells have successfully lighted up a red-light emitting diode (LED), proving its outstanding supercapacitive performance as an excellent electrode material for supercapacitors. • High performance supercapacitor composed of CNFs/PANI-MnO 2 was synthesized. • CNFs/PANI-MnO 2 showed synergistic enhancement in specific capacitance. • CNFs/PANI-MnO 2 presented remarkable specific energy with good cyclability. • Three assembled coin cells were capable to illuminate a red LED. [ABSTRACT FROM AUTHOR]