KNO3 Electrolyte Research Articles

Trace Cu-Induced Low C─N Coupling Barrier on Amorphous Co Metallene Boride for Boosting Electrochemical Urea Production.

The electrochemical C─N coupling of carbon dioxide (CO2)and nitrate(NO3 -)is an alternative strategy to the traditional high-energy industrial pathway for urea synthesis, which urgently requires the design of efficient catalysts to achieve high yield and Faraday efficiency (FE). Here, amorphous low-content copper-doped cobalt metallene boride (a-Cu0.1CoBx metallene) is designed for urea synthesis via electrochemical C─N coupling. The a-Cu0.1CoBx metallene can drive electrocatalytic C─N coupling of CO2 and NO3 - for urea synthesis in CO2-saturated 0.1m KNO3 electrolyte, with 27.7% of FE and 312µgh-1mg-1 cat. of yield at -0.5V, as well as superior cycling stability. The in situ Fourier transform infrared and theoretical calculations reveal that electronic effect between Cu, Co, and B causes Cu and Co as dual active sites to promote the adsorption of reactants. Furthermore, the introduced trace Cu reduces the reaction energy barrier of the C─N coupling to facilitate urea synthesis. This work provides a promising route for the optimization of Co-based metallene for the electrosynthesis of urea through C─N coupling.

Enhancing cyclic stability of Mn-based Prussian blue cathode for Potassium Ion storage by High-spin Fe substitution strategy

Aqueous K-ion batteries (AKIBs) are being considered as promising candidates, although they still confront numerous problems. Here we propose a high-spin Fe substitution method to enhance the long-term cyclic stability of Mn-based Prussian blue analogue (Mn-PBA) cathode. The prepared K1.86Mn[Fe(CN)6]0.96·0·19H2O (KMF) are electrochemically activated for 20-cycle CV scan in the hybrid electrolyte containing KNO3+Fe(NO3)3. The modified cathode (KMF-100) achieves a high capacity of 185.8 mAh g−1 and high-capacity retention of 89.8 % at 2 A g−1 after 1500 cycles (based on maximum capacity). The high-spin Fe substitution strategy not only activates the transition metal at high spin sites to contribute extra capacity, but also promotes the partial dissolved Mn2+ to return to the PBA in the hybrid electrolyte with Fe3+, relieving the Jahn-Teller effect of Mn(Ⅲ). In contrast, the KMF in the pure KNO3 electrolyte does not exhibit this behavior. The DFT calculation further demonstrate the reconstituted Prussian blue structure can increase the electrical conductivity and improve ion diffusion kinetics of the cathode material. Notably, it suppresses the change in C-Fe bond lengths during K-ion extraction, maintaining outstanding structural stability throughout cycle. This work provides a novel way to prepare high-stability manganese-based PBA cathode.

Self-supporting electrode incorporating active Co sites for ultrafast ammonia production from nitrate reduction

Electrocatalytic nitrate (NO3−) reduction reaction (NitRR) provides us a green solution to synthesize ammonia (NH3) and ease environmental problems. However, the development of robust electrodes with high NH3 yield rates and Faradaic efficiencies (FEs) is still challenging. Herein, we report a self-supporting electrode incorporating vertically aligned Co-based metal-organic framework (MOF) nanosheets (Co-NDC/NF), which facilitates electron and mass transfer for efficient NitRR to NH3 within a wide range of NO3− concentration (0.05−1.0 M). In 1.0 M KOH + 1.0 M KNO3 electrolytes, such Co-NDC/NF reaches a notable NH3 yield rate of 19,200 ug h−1 cm−2, a high FE of 93.9% and excellent electrochemical stability, which is superior to most electrocatalysts. A flow-through reactor with large-area Co-NDC/NF also achieves the continuous production of 1096 mg L−1 NH3 under an industrial current density. Furthermore, the rapid transformation of *NO2− to *NO and selective conversion of *NO to *NOH played critical roles in NitRR toward ultrafast NH3 production. Our research not only offers a facile fabrication procedure for high-performance electrode, but also gives new insights into the enhanced electron transfer and mass transport within MOF-based electrode in electrochemical reactions.

Dissolution kinetics of copper oxide nanoparticles in presence of glyphosate

Recently CuO nanoparticles (n-CuO) have been proposed as an alternative method to deliver a Cu-based pesticide for controlling fungal infestations. With the concomitant use of glyphosate as an herbicide, the interactions between n-CuO and this strong ligand need to be assessed. We investigated the dissolution kinetics of n-CuO and bulk-CuO (b-CuO) particles in the presence of a commercial glyphosate product and compared it to oxalate, a natural ligand present in soil water. We performed experiments at concentration levels representative of the conditions under which n-CuO and glyphosate would be used (∼0.9 mg/L n-CuO and 50 μM of glyphosate). As tenorite (CuO) dissolution kinetics are known to be surface controlled, we determined that at pH 6.5, T ∼ 20 °C, using KNO3 as background electrolyte, the presence of glyphosate leads to a dissolution rate of 9.3 ± 0.7 ×10−3 h−1. In contrast, in absence of glyphosate, and under the same conditions, it is 2 orders of magnitude less: 8.9 ± 3.6 ×10−5 h−1. In a more complex multi-electrolyte aqueous solution the same effect is observed; glyphosate promotes the dissolution rates of n-CuO and b-CuO within the first 10 h of reaction by a factor of ∼2 to ∼15. In the simple KNO3 electrolyte, oxalate leads to dissolution rates of CuO about two times faster than glyphosate. However, the kinetic rates within the first 10 h of reaction are about the same for the two ligands when the reaction takes place in the multi-electrolyte solution as oxalate is mostly bound to Ca2+ and Mg2+.

Yolk-shell composite oxides with binuclear Co(II) sites toward low-overpotential nitrate reduction to ammonia

Electroreduction of nitrate to ammonia, a potential route for producing ammonia, is still confronted with a great challenge on developing efficient electrocatalysts. In this work, a reduced yolk-shell Co-based oxides (R-Co3O4) electrocatalyst with oxygen vacancy-rich Co3O4 and CoO was designed for nitrate reduction. This catalyst presented a nearly 100 % Faradaic efficiency (FE) of ammonia in a low potential from −0.05 to −0.1 V vs. RHE, and a maximum ammonia production rate of 7.25 mg h−1 mgcat.-1 at −0.05 V vs. RHE in 0.1 M KOH + 1000 ppm KNO3 electrolyte. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) pattern proved that the content of Co2+ was dramatically increased in R-Co3O4. The kinetic correlation experiments and Operando Raman spectra preliminarily manifest that the potential limiting step is the reduction of adsorbed *NO3. The density functional theory (DFT) calculations consistently demonstrated that on both oxygen-rich Co3O4 and CoO, the adsorption of key intermediates (*NO3, *NO and *NH) are greatly enhanced on the bridge site between two Co2+, boosting the nitrate reduction at low over-potential. This work is helpful to design the catalytic material with rich and low-valence sites towards electroreduction of nitrate to ammonia.

Electrochemical oxidation of tetrahydrofurfuryl acohol on boron-doped diamond anode: Influence of current density and electrolyte solution

Tetrahydrofurfuryl alcohol (THFA), a widely applied raw materials, intermediate and solvent in the fields of agricultural, industry (especially in nuclear industry), is a potentially hazardous and non-biodegradable pollutant in wastewater. In this study, the electrochemical degradation pathways of THFA by a boron-doped diamond (BDD) anode with different current density (jappl = 20, 40 and 60 mA cm−2) and electrolyte solution (KNO3, KCl and K2SO4) was carefully investigated. The results exhibit that high chemical oxygen demand (COD) removal and mineralization rates were achieved by rapid non-selective oxidation in electrolyte solutions mediated by hydroxyl radicals (∙OH) and active chlorine (sulfate) under constant current electrolysis. In-depth data analysis using the high performance liquid chromatography and liquid chromatography/mass spectroscopy, the underlying removal pathways of THFA in KNO3, KCl and K2SO4 electrolyte solutions are proposed according to the effect of different mineralization mechanisms.

Chitosan and Metal Oxide Functionalized Chitosan as Efficient Sensors for Lead (II) Detection in Wastewater

The work presented in this paper describes the preparation and the electrochemical application of functionalized chitosan-entrapped carbon paste electrodes (CH/CPE) for lead ions (Pb2+) detection in industrial wastewater. The chitosan was first functionalized using TiO2 and CuO, which were both metal oxides that were obtained by extracting it from waste products derived from shrimp shells. The analytical performance of the as-prepared electrodes, CH/CPE, TiO2-CH/CPE, and NiO-CH/CPE, for the detection of lead (II) was examined using electrochemical impedance spectroscopy (EIS) technique in the 0.1 M KNO3 electrolyte solution. The effect of experimental conditions, including polarization potential, frequency, and pH, are optimized to maximize the sensitivity of the measurements. The developed impedimetric sensors provided a linear response over a concentration range of 10−6 to 10−4 M with a detection limit of 3.10−7 M based on S/N = 3. The DFT computational analysis demonstrated that chitosan biopolymer possesses the ability to adsorb Pb (II) ions that are present in wastewater. Chitosan and the derivatives of chitosan, have the potential to remove heavy metals from industrial effluent in a manner that is both economical and eco-friendly to the environment. Chitosan is a biopolymer that is abundantly renewable.

Biomass valorisation of marula nutshell waste into nitrogen-doped activated carbon for use in high performance supercapacitors

This study reports on the valorisation of marula nutshell waste into a valuable electrode material for supercapacitors. Marula nutshell waste, a brown hard residue from marula fruits was valorised into a nitrogen-doped activated carbon (N-ACs) by KOH treatment and using melamine as a nitrogen source. The microporous and mesoporous nature of N-ACs exhibited a high surface area of 1427 m² g−1 and pore volume of 0.31 cm3 g−1. Three electrode measurements were done in 6 M KOH and 2.5 M KNO3 aqueous electrolytes, to examine the materials in alkaline and neutral medium. The N-ACs exhibited a capacitance of 350 F g−1 in 6 M KOH and 248 F g−1 in 2.5 M KNO3 electrolyte. Due to low toxicity and wider operating voltage (∼1.8 V) of 2.5 KNO3, the material was further analysed in a symmetric device. The high surface area, the defects, and the high content of nitrogen (5.1%) revealed that the material produced an outstanding energy density of 17.2 Wh kg−1 and a power density of 448.7 W kg−1 in 2.5 M KNO3 electrolyte. The conversion of marula nuts waste into N-ACs thus provide a means of converting biomass waste into a useful energy storage material for supercapacitors.

Multi-layer core-shell metal oxide/nitride/carbon and its high-rate electroreduction of nitrate to ammonia.

The electroreduction of nitrate to ammonia is both an alternative strategy to industrial Haber-Bosch ammonia synthesis and a prospective idea for changing waste (nitrate pollution of groundwater around the world) into valuable chemicals, but still hindered by its in-process strongly competitive hydrogen evolution reaction (HER), low ammonia conversion efficiency, and the absence of stability and sustainability. Considering the unique electronic structure of anti-perovskite structured Fe4N, a tandem disproportionation reaction and nitridation-carbonation route for building a multi-layer core-shell oxide/nitride/C catalyst, such as MoO2/Fe4N/C, is designed and executed, in which abundant Fe-N active sites and rich phase interfaces are in situ formed for both suppressing HER and fast transport of electrons and reaction intermediates. As a result, the sample's NO3RR conversion displays a very high NH3 yield rate of up to 11.10 molNH3 gcat.-1 h-1 (1.67 mmol cm-2 h-1) with a superior 99.3% faradaic efficiency and the highest half-cell energy efficiency of 30%, surpassing that of most previous reports. In addition, it is proved that the NO3RR assisted by the MoO2/Fe4N/C electrocatalyst can be carried out in 0.50-1.00 M KNO3 electrolyte at a pH value of 6-14 for a long time. These results guide the rational design of highly active, selective, and durable electrocatalysts based on anti-perovskite Fe4N for the NO3RR.

Facile and sustainable technique to produce low-cost high surface area mangosteen shell activated carbon for supercapacitors applications

In this study, we have reported the effect of different activating agents, temperatures, and impregnation ratios on the porosity of mangosteen shell-derived activated carbons (M-S AC). The sample’s characterization comprised of scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, and N2 physisorption analysis. The M-S AC synthesized with K2CO3 as the activating agent displayed a high specific surface area of 2802.6 m2 g−1 and a flower-like morphology. Electrochemical measurements of the M-S AC synthesized with K2CO3 revealed a specific capacitance of 298.13 F g−1 at 0.5 A g−1 in a potential window of −0.9–0.0 V vs Ag/AgCl using 2.5 M KNO3 electrolyte in a three-electrode measurement. An initial symmetric supercapacitor assembled with the optimized M-S AC as electrode material and 2.5 M KNO3 as the electrolyte delivered a specific energy of 11.5 Wh kg−1 corresponding to a specific power of 0.4 kW kg−1 at 0.5 Ag−1 in a potential window of 1.6 V. A second assembled symmetric device using the same M-S AC as electrode material and 1-Ethyl-3-methylimidazolium-bis(fluoroSulfonyl)imide (EmiFSI) ionic liquid as the electrolyte demonstrated high specific energy of 28.03 Wh kg−1 corresponding to a specific power of 0.7 kW kg−1 at 0.5 Ag−1 in a wider potential window of 2.8 V.

Asymmetric Ultracapacitor Produced By Sulphur Reduced Graphene Oxide/Metal Oxide Composite with High Energy Density and Outstanding Cycling

The morphology comprises of nano-rods/fibers, nano-sheet and nano-flower like structure were successfully produced from sulphur reduced graphene oxide/manganese dioxide composite for ultracapacitor application. The electrochemical evaluations of the optimal sample presented a specific capacitance of 180.40 F g-1 at 1 A g-1 in 2.5 M KNO3 electrolyte in a three-electrode set-up. An asymmetric device made up of sulphur reduced graphene oxide/manganese dioxide composite and activated carbon as a positive and negative electrode, respectively, delivered a high specific energy and power of 71.74 Wh kg-1 and 850 W kg-1 at 1 A g-1. It was further noticed that the device was able to retain a specific energy of 55.30 Wh kg-1 even at high specific current of 5 A g-1. An outstanding cycling stability with a capacitance retention of 94.5 % and energy efficiency of 99.9 % for up to 10,000 cycles was noted at 5 A g-1. The device revealed an excellent stability after being subjected to a voltage holding of up to 90 h and an exceptional self-discharge of about 1.45 V was recorded within the first 10 h and 1.00 V after 72 h from its maximum voltage of 1.7 V. The results obtained confirms that the produced material offers a great potential for the application of high energy density supercapacitor. Keywords: Graphene oxide; Energy density; Supercapacitor; Shuttle effects; Composite materials; Sulphur.

Enhanced electrochemical behavior of Mg-doped MnO2 for supercapacitor application

In this research work, we have prepared the pure and Mg-doped MnO2 nanostructures as electrode material via the facile hydrothermal method. The structure, crystallite size, and morphology of the synthesized samples were characterized using powder X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM). The X-ray diffraction pattern indicated the tetragonal phase formation of MnO2 nanostructures without any impurity peak. The average crystallite size was calculated by means of the Scherrer formula. SEM study also revealed the formation of nanofibres and nanorods, which enhanced the charge storage capability. Electrochemical performances for pure as well as doped MnO2 samples are also examined in the three-electrode set-up by utilizing the techniques like Electrochemical Impedance Spectroscopy, Cyclic Voltammetry, Galvanostatic Charge Discharge. The specific capacitance of 240.5F/g at 0.5 mA is obtained in the KNO3 electrolyte for the synthesized pure material. Mg doping enhanced the electrochemical performance by nearly 1.5 times and obtained the capacitance of 360F/g at 0.5 mA which can be attributed to the increased lattice defects and oxygen vacancies due to the incorporation of Mg2+ ions in the matrix of MnO2. Therefore, as a consequence of electrochemical performance, Mg-doped MnO2 nanostructures are ideally suitable for supercapacitor applications.

3D Prussian blue decorated porous carbon composite electrode for advanced asymmetric supercapacitor applications

Irrational use of fossil fuels led to global warming and pollution. Therefore, the newer technologies should be sustainable and eco-friendly to combat climate change. In this context, supercapacitors (SCs) are demonstrated with carbon materials derived from natural biomaterials. The utilization of biomass-derived materials in energy storage not only converts biowaste material to value-added products but also reduces the production cost. Although SCs exhibit high power density, they are not considered a primary energy source due to their poor energy density. By taking advantage of the present work's asymmetric configuration, the operating voltage window and energy density of aqueous SCs are significantly enhanced. An asymmetric SC is developed by combining a porous 3D cubical-shaped Prussian blue (PB) decorated carbon derived from tamarind seeds (ACTS-800) (PB/ACTS-800) positive electrode with ACTS-800 negative electrode and aqueous 3 M KNO3 electrolyte. The resulting ACTS-800//PB/ACTS-800 (1:2) asymmetric SC demonstrated a broad electrochemical stable voltage window of 2.2 V in the aqueous medium. Impressively, a high energy density of 60 Wh/kg @ 551 W/kg realized is much superior to most of the carbon/carbon SCs operated in an aqueous medium.

Binder-Free MnO2 Electrodes for Supercapacitor Applications

The binder-free MnO2 electrodes are fabricated using the electro-deposition method. X-ray diffraction spectra of the obtained electrodes verified the generation of a pure tetragonal phase of MnO2 without any impurity peak. Further, the morphology of the fabricated electrode is explored by Scanning Electron Microscope, which confirmed the formation of platelets when the deposition time is small, while the flakes are formed as the deposition time is increased. Electrochemical performances for all three fabricated MnO2 electrodes are also conducted in the three-electrode system using the techniques like Cyclic Voltammetry, Galvanostatic Charge Discharge, and Electrochemical Impedance Spectroscopy. The maximum specific capacitance of 531.6 F/g at 0.5 A/g is achieved in the KNO3 electrolyte for the electrode with 15 minutes of deposition time, while the high rate capability is maintained for the electrode with a deposition time of 10 minutes. Therefore, based on the electrochemical performance, fabricated MnO2 electrodes are suitable for supercapacitor applications.

Electrochemical energy storage on nanoporous copper sponge

A proof-of-principle double-layer symmetrical supercapacitor with nanoporous copper/copper oxide electrodes and an aqueous electrolyte is investigated. The electrodes are manufactured by selective dissolution of Al from a eutectic composition of Cu17.5Al82.5 using 5 M NaOH. The ostensible (i.e., net external) capacitance of a symmetrical two-electrode cell with 0.1 M KNO3 electrolyte is assessed over a series of charge/discharge cycles and is about 2 F per gram of Cu in this simple prototype. Capacitance varies during a discharge cycle due evidently to the deeply buried surfaces and pseudocapacitive reactions contributing charge toward the end of a discharge cycle. In principle such a device should have very low ohmic losses due to its highly conductive backbone and would be suitable for applications requiring maximum energy efficiency over repeated cycling. The aqueous electrolyte ensures fire safety but this comes at the cost of lower energy content.Graphical abstract

Microwave-assisted reflux synthesis of spherical Co2Fe(CN)6 nanoparticles for high-performance asymmetric supercapacitors

The open framework materials with the Prussian blue structure facilitate the insertion of monovalent K+ ions and exhibit high capacitive performance. In this regard, the spherical Co2Fe(CN)6 (Co-HCF) nanoparticles were synthesized by the microwave-assisted reflux method. The X-ray diffraction pattern confirms the cubic structure, and the transmission electron microscopy images reveal the formation of spherical sized particles. The cyclic voltammetry analysis corroborated the reversibility of the electrode and delivered the specific capacitance of 1131 F g−1 at 2 mV s−1 in 1 M KNO3 electrolyte. Further, the 2 V asymmetric supercapacitor (Co-HCF//AC) was fabricated with activated carbon, which delivers the specific capacitance of 50 F g−1 at 10 mV s−1 and the energy density of 24.06 Wh kg−1 at the power density of 103.7 W kg−1 at 1 A g−1 with cycling stability of nearly 84% over 1000 cycles.

Effect of hydrothermal temperature on structural, optical and electrochemical properties of α-MnO2 nanostructures for supercapacitor application

One dimensional α-MnO2 nanostructures are obtained via a facile hydrothermal method without extra surfactants and additives with different morphologies by varying the hydrothermal temperature. X-ray diffraction (XRD) and Raman spectroscopy confirmed the tetragonal α-MnO2 phase. FESEM analysis revealed the morphological variation from nanorods to nanofibres. Electrochemical characterizations like CV, GCD, and EIS were utilized to analyze the supercapacitive properties of the synthesized electrode material in a three-electrode cell using 1 M KNO3 electrolyte. The highest specific capacitance of 218.8 Fg−1 at 0.5 Ag−1 is obtained for sample M1, and GCD determines excellent cycle stability with 92% retention after 5000 cycles.

Functionalization of graphene oxide via chromium complexes coordinated on 5-aminopyridine-2-carboxylic acid as a symmetric supercapacitor electrode materials in energy storage devices

In the present study, the functionalization of graphene oxide (GO) via 5-Aminopyridine-2-carboxylic acid Cr (ш) complex (FGO-Ap/Cr) was fulfilled using a one-pot hydrothermal method. Then, the synthesized FGO-Ap/Cr was evaluated through Fourier transform infrared (FT-IR) spectrometry and X-ray photoelectron spectroscopy (XPS). The electrochemical functionality of the given electrodes was then analyzed using cyclic voltammetry (CV), chronopotentiometry, and electrochemical impedance spectrometry (EIS). A high specific capacitance of 461.5 F g−1 is achieved at a current density of 1 A g−1 for the FGO-Ap/Cr in three electrodes electrochemical measurement. These electrodes show remarkable electrochemical behaviors for supercapacitors (SCs) with regard to incredible rate capacity, elevated specific capacitance, and superb cycle stability. A high energy and power density symmetric supercapacitor was also successfully designed using FGO-Ap/Cr and GO, as the anode and cathode electrodes in a neutral 3 M KNO3 electrolyte. Due to the desired poriferous construct, the elevated specific capacitance, the rated capacity, and the complemental potential of the three electrodes, the asymmetrical supercapacitor is capable of revolving in a full potential window of 0–1.7 V with an energy density of 523.3 W h kg−1 at a power density of 98111.3 W kg−1 for FGO-Ap/Cr//GO. Besides, the symmetrical supercapacitor showed steady cycling functionality for FGO-Ap/Cr//GO capacitance retention at 8 A g−1 following 5000 cycles, with 96.2%. These encouraging results demonstrate a high potential for practical applications in the development of energy-storing equipment with elevated energy and power concentrations.

Hybrid electrochemical supercapacitor based on birnessite-type MnO2/carbon composite as the positive electrode and carbonized iron-polyaniline/nickel graphene foam as a negative electrode

In this work, a birnessite-type MnO2/carbon composite with hierarchical nanostructures was synthesized using KMnO4 solution and spent printing carbon grains. A hybrid electrochemical supercapacitor device was fabricated based on the birnessite-type MnO2–carbon composite electrode and carbonized iron-polyaniline/nickel graphene foam as positive and negative electrodes, respectively. At the lowest specific current of 1.0 A g−1 and cell potential of 2.2 V in 2.5M KNO3 electrolyte, the device displayed a high energy and power density of 34.6 W h kg−1 and 1100.0 W kg−1, respectively. The device further displayed long-term cycling stability with a capacitance retention of 98% over 10 000 galvanostatic charge–discharge cycles at 10 A g−1. This device displays the overall excellent electrochemical performance.

High energy and excellent stability asymmetric supercapacitor derived from sulphur-reduced graphene oxide/manganese dioxide composite and activated carbon from peanut shell

Nanorods/fibers, nanosheet and nano-flower like structure were effectively synthesized from sulphur-reduced graphene oxide (RGO-S) and sulphur-reduced graphene oxide/manganese dioxide (RGO-S/MnO2) composites for supercapacitor applications. Structural, chemical composition and morphological analysis reveal an effective synthesis of the RGO-S and RGO-S/MnO2 composite. Electrochemical measurements of the optimized mass loading of MnO2 on RGO-S in a three electrode configurations revealed a specific capacitance of 180.4 F g−1 compared to 75.2 F g−1 of the pristine sample at 1 A g−1 in 2.5 M KNO3 electrolyte. An assembled asymmetric device consists of optimized RGO-S/MnO2 as positive electrode and activated carbon from peanut shell (AC-PS) as a negative electrode delivered a high specific energy of 71.74 Wh kg−1 with its corresponding specific power of 850 W kg−1 at 1 A g−1. It was observed that even at high specific current of 5 A g−1 the device was able to maintain a specific energy of 55.30 Wh kg−1. An excellent stability with capacitance retention of 94.5% and columbic efficiency of 99.6% up to 10, 000 cycles was recorded for the device at 5 A g−1. The device demonstrated a very good stability after being subjected to a voltage holding of up to 90 h and an outstanding self-discharge of about 1.45 V was recorded within the first 10 h and 1.00 V after 72 h from its maximum potential of 1.7 V.