Increase In Specific Capacitance Research Articles

Highly scalable and low cost binder free electrode of Zinc modified NiO nanofoam for dual role of supercapacitor and its free radical scavenging activity

In this study, pristine nickel oxide (NiO) and Zinc modified NiO nanofoams were prepared by green approach using camellia sinensis leaves extract. Pristine nickel oxide and Zn2+ modified NiO nanofoam were characterized by XRD, FTIR, FL, UV and FESEM. FE-SEM micrographs were clearly shows that the synthesised porous nanofoam with spherical shaped were constant distribution. The as prepared foam electrodes showed excellent supercapacitive behaviour with increase in specific capacitance with decrease in scan rate. The maximum specific capacitance 1530, 1706 and 1847Fg-1 was obtained at scan rate of 10 mVs-1 for increasing the Zn concentrations. After 3,000 cycles at 1 A g−1, the cyclic stability remains excellent at 88.1% of the initial capacitance. Moreover, the as-prepared asymmetric supercapacitor exhibits a high energy density of 30.6 W h·kg−1 at power density of 398 W kg−1. This study is expected to provide new insights into exploring the potential mechanism of catalyst action. These findings show that Zinc @ NiO nanofoam could be a potentially useful electrode material for energy storage devices.

Enhancement of electrochemical performance of lithium manganese oxide with graphene for aqueous supercapabattery

In this study, we synthesized lithium manganese oxide nanoparticles/graphene nanoplatelets (LMO/GNPs) as the cathode material for a supercapabattery using a hydrothermal method. The addition of GNPs resulted in a 63% and 68% increase in specific capacitance and capacity compared to LMO alone, attributed to the enhanced conductivity and efficient lithium-ion diffusion of GNPs. The LMO/GNPs exhibited excellent rate capability and stability, with 80% capacity retention after 1000 cycles, an energy density of 39.07 Wh kg−1 and a power density of 925.40 W kg−11, showcasing their potential for supercapabattery applications. These findings highlight the superior performance of LMO/GNPs in the supercapabattery, making it a promising energy storage solution.

Different carbonization temperature effect on Mo2C/MWCNT hybrid structure formation for enhanced supercapacitor performance

Various forms of energy used in our daily lives prevail in contemporary society. Application requirements have expanded from high power density to sustainable long term energy density for energy storage devices. The present study signifies effect of carbonization temperature role (700 °C, 800 °C, 900 °C) on electrochemical studies of MoO3 as electrode in supercapacitor devices. The prepared electrodes were characterized by electrochemical studies such as cyclic voltammetry (CV), galvanostatic charge discharge (GCD) and electrochemical impedance spectroscopy (EIS) and basic characterizations like X-ray diffraction, Raman, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM). Different carbonization temperatures with the addition of carbon precursors produced MoO2/MWCNT and α-Mo2C/MWCNT. The areal capacitance of MoO2–700 °C, MoO2–800 °C, α-Mo2C-900 °C electrode were found to be delivered as 0.45 F/cm2, 0.54 F/cm2, 0.96 F/cm2 at 0.003 A/cm2. The substantial increase in specific capacitance for α-Mo2C-900 °C was attributed to improve charge transport, faradic redox development occurring at electrode surface, and high electrical conductivity of carbon nanotubes.

Cellulose nanofibers as a green binder for symmetric carbon nanotubes-based supercapacitors

The demand for flexible lightweight supercapacitors (FSCs), mainly applied in flexible electronics, has spun by the ever-increasing energy storage market. To meet the market criteria, electrodes with high porosity and specific surface areas are ideal candidates as lightweight and flexible supercapacitors components. This work highlights the use of nanocellulose as a bio-derived binder for flexible supercapacitors. This binder contributes to the enhancement of electrochemical performance due to its 1D fibrous hierarchical structures. In turn, nanocellulose is a promising candidate for medical and implantable devices owing to its biocompatibility. Here, we report the fabrication of freestanding, flexible, porous, and conductive electrodes via a facile scalable fabrication process. The electrodes are comprised of multi-walled carbon nanotubes as the conductive material and cellulose nanofibers as the bio-based binder. Due to the combined synergistic effect of carbon nanotubes and cellulose nanofibers, the fabricated electrodes show a high porosity. The effect of cellulose type was evaluated at 16 wt.%, which showed no significant effect on the electrochemical performances at this percentage. However, we demonstrate that the cellulose dry content for a specific cellulose type affects the electrochemical performances, with optimized performances for a dry cellulose percentage between 4 and 6 wt.%. In these formulations, the ratio between nanocellulose and CNTs contributes to the formation of porous and conductive nanosheets. The samples’ porosity was assessed regarding their specific surface area (N2 Adsorption-desorption) while scanning electron microscopy (SEM) emphasized their morphology. Due to the high porosity as well as conductivity, the samples showed a good specific capacitance (∼ 9 F/g) and outstanding cycling stability with an increase in specific capacitance of about 10% after 3500 cycles at 0.13 A/g.

Electrodeposition of manganese dioxide coatings onto graphene foam substrates for electrochemical capacitors

Optimisation of electrodeposition routes of birnessite manganese dioxide (MnO2) coatings onto 3D graphene foam substrates enabled greater attainable capacitances. Current pulse deposition method resulted in highest achievable areal capacitance of 530 mF/cm2 under a 10 mA/cm2 current rate, cycling performance with 91% retention after 9000 cycles, as well as improved rate capability when compared to the cyclic voltammetry or galvanostatic deposition. Introduction of oxygen functional groups to the graphene foam added initial pseudocapacitance and accelerated the rate for nucleation and growth of the MnO2 crystal grains, resulting in an areal capacitance of 410 mF/cm2 under a 10 mA/cm2 current rate. However, in this case the increase in specific capacitance was accompanied by sluggish kinetics for charge storage seen via impedance spectroscopy. The charge storage mechanism of the deposited MnO2 films was investigated using in situ Raman microscopy and analysis of peak shifts revealed expansion and contraction of birnessite MnO2, relating to exchange of Na+ and H2O at the MnO2 interface.

Supporting electrolyte enhanced supercapacitance of acetic acid doped reduced graphene oxide/nickel hydroxide/polyaniline nanocomposites

The rapidly enhanced electrolytic intercalation bringing about 101 % higher energy storage in rGO, Ni(OH)2 and PANI (GNP) nanocomposite in comparison with 1 M H2SO4 is achieved using the 0.4 M CH3SO3H (MSA) as supporting electrolyte for 0.4 M H2SO4 (SA). Ensuing the established fact of acid insoluble Ni(OH)2 in our earlier study, the further work on Ni(OH)2 containing composites in the presence of acid electroytes has proven its stability in MSA as well. The GNP exhibited increase in specific capacitance (Cs) on increasing the cycles of energy storage and delivery in different acid electrolytes but the enhancement in the presence of MSA is higher. The superior results were achieved from the supercapacitor device containing GN51P (rGO 3.70 %: Ni(OH)2 51.86 %: PANI44.44 %) and SA + MSA, which are, Cs of 381.67 F g−1, specific capacity (Q) of 458.01 C g−1, E of 76.33 W h kg−1 and a specific power of 3.3109 kW kg−1 at 1 A g−1. The GN51P exhibited increasing Cs even after 10,000 cycles at 400 mV s−1. The real time applications of the GNP composites are also experimented satisfactorily.

A two-pronged strategy to modulate the porosity of porous carbons for capacitors: The relative effects of the texture and fuel properties of carbonaceous matter

Based on the search for a novel method to modulate the texture properties of porous carbon, it is essential to demonstrate the relative influence of texture and fuel properties (i.e., the general term of volatile, fixed carbon, ash, elements, and calorific value) of carbonaceous matter. Herein, H3PO4 activation was applied to fabricate pine sawdust-derived porous carbons (PC-T; T can be 450, 500, 550, and 600) with various fuel and texture properties. Afterward, the pore architectures recorded for PC-T were adjusted using the CO2 activation procedure; that is, PC-T-derived porous carbons (PC-TC) were obtained. PC-TC showed a significant increase in texture properties (e.g., specific surface area and total pore volume) and specific capacitance compared to PC-T. In the three-electrode configuration, PC-550C achieved high specific capacitance values (e.g., 230.78 F/g at 0.5 A/g). The assembled PC-550C-based symmetrical supercapacitor achieved an impressive specific capacitance of 172.12 F/g upon 0.5 A/g. Interestingly, it equally delivered high energy density (23.91 Wh kg−1) and power density (47.30 kW kg−1), respectively. Further, the specific surface area of the PC-TC samples depends not only on the fuel properties of the PC-T samples but also on the texture properties of the PC-T samples. Superior fabricability and variable texture properties enable the two-pronged strategy (i.e., sequential H3PO4–CO2 activation) for producing bulk senior and multi-level porous carbons.

Engineering Multifunctionality in MoSe2 Nanostructures Via Strategic Mn Doping for Electrochemical Energy Storage and Photosensing

To achieve advanced functionalities in nanostructured MoSe2 for enhanced electrochemical charge storage and improved photosensing, here we propose an effective strategy, i.e., the substitutional doping of the heteroatom Mn. We achieve a 313% increase in specific capacitance for 6.2% of Mn doping compared to pristine MoSe2 at the scan rate of 5 mV/s in a three-electrode configuration. For a two-electrode arrangement, also superior charge-storage performance is noted. The enhanced electrode performance can be attributed to the increase of electrical conductivity arising due to an increase of electron density for the n-type nature of Mn doping realized via an X-ray photoelectron spectroscopy study and density functional theory calculation. The latter one also unveils that Mn doping introduces catalytically active sites by disrupting homogeneous charge distribution over the topology of the MoSe2 basal plane contributing to better charge-storage performance. Mn doping-induced shift in the Fermi level of MoSe2 toward the conduction band also minimizes the contact barrier height signifying its improved capabilities for a photosensor device. Additionally, Mn doping causes alleviation of the charge-recombination process resulting in increase of photocarrier separation. As a result, we observe a 187% enhancement in the photocurrent and significantly higher responsivity and detectivity for 6.2% Mn-doped MoSe2 than its pristine counterpart. Our proposed doping strategy to modulate charge storage as well as photoresponse properties demonstrates high potential for MoSe2 along with other two-dimensional transition-metal dichalcogenides in developing next-generation energy-storage and optoelectronic devices.

Enhanced performance with ionic and organic redox-couple electrolytes on MTMO anchored CQD nanocomposites and renewable carbon-based asymmetric flexible supercapacitor

The work utilizes a hybrid approach at electrode and electrolyte systems to fabricate a high-energy density supercapacitor. Hybrid nanocomposite electrodes were fabricated using a facile hydrothermal synthesis. The kinetics were studied by preparing in-situ and ex-situ nanocomposites. The in-situ preparation delivers a homogeneous flower petal-like interconnected porous morphology with an appreciable BET surface area of 97 m2 g−1. The actual electrochemical performance was analyzed by accounting for discharge area instead of discharge time to avoid discrepancies related to hybrid energy storage systems. The three-electrode measurement suggests that the electrode delivers an excellent specific capacitance of 3802 F g−1 at 1 A g−1. In the asymmetric configuration, the device reveals excellent actual specific capacitance of 292 F g−1 at 1 A g−1. However, upon adding 0.02 M KI as redox mediators in a traditional electrolyte (6 M KOH), a ∼37% increase in specific capacitance is achieved without the degradation in the device stability. The nanoarchitecture porous morphology and modification in traditional electrolyte enables a high-performance device having an energy density of 165 Wh kg−1 at a power density of 1000 W kg−1, which retain till 50 Wh kg−1 at 25 kW kg−1. The nanocomposite also shows excellent compatibility in a flexible device assembly, delivering a specific capacitance of 192 mF cm−1 at 1 mA cm−1 without deteriorating its performance upon different bending angles. The study claims the design of a low-cost, environmentally benign, and facile approach for developing a high-performance hybrid supercapacitor.

Employing Redox‐Active Additives for Enhanced Charge Polarization and Twofold Higher Energy Density in Supercapacitor

AbstractRemarkable improvement in the polarization and charge transport at the solid–solid electrode–electrolyte interface due to the incorporation of a redox‐active additive sodium molybdate (Na2MoO4) is demonstrated. The presence of the electrochemically active oxide center along with Na+facilitates the hopping‐based charge transport of the ionic liquid leading to higher ionic conductivity and a twofold increase in specific capacitance (0.009 to 0.018 F cm−2). This drives a 200% increase in the energy density (0.76–1.7 µW h cm−2) and a 2.5 times improvement in the rate capability (10 000 mV s−1) of the solid‐state supercapacitor. Importantly, the power density, non‐Faradic nature, and cyclability remain unaltered, resulting in performance exceeding several solid‐state and liquid electrolyte‐based supercapacitors. Thus, the results established here through the use of redox‐active additive establish the robustness of the approach and practicality of the resulting device besides providing transformative opportunities in tuning the performance of solid‐state devices.

Hydrodynamic cavitation-assisted preparation of porous carbon from garlic peels for supercapacitors

Hydrodynamic cavitation (HC), which can effectively induce sonochemical effects, is widely considered a promising process intensification technology. In the present study, HC was successfully utilized to intensify the alkali activation of GPs for SCs, for the first time. Five BDCMs were synthesized following the method reported in the literature. For comparison, four more BDCMs with HC-treated, among which a sample was further doped with nitrogen during the HC treatment, were prepared. Then all the samples were compared from microscopical characteristics to electrochemical performance as SCs materials. The morphology study demonstrated that the HC treatment had created many defects and amorphous carbon structures on the GP-based BDCMs, with the highest SSA reaching 3272 m2/g (1:6-HCGP), which 32 folded that of the Raw carbon sample’s. The HC treatment also intensified the N-doping process. XRD and XPS results manifested that the N content had been increased and consequently changed the electronic structure of the carbon atoms, leading to the increase of specific capacitance (1:6-HCGP+N-based SC, 227 F/g at 10 A/g). The cycle performance proved that the GP-based BDCMs have long-term stability, indicating that the HC-treated BDCMs were good choices for energy storage technologies. Compared with the ultrasound-assisted method, which may have a high energy density, the HC-assisted method enables high production and energy efficiency. This work is a first time attempt towards the industrial application of HC method in energy-related materials synthesis and encourages more in-depth studies in the future.

Efficient Oxygen Doping of Graphitic Carbon Nitride by Green Microwave Irradiation for High-Performance Supercapacitor Electrode Material

A highly efficient microwave irradiation method was employed for doping oxygen into the g-C3N4 framework using H2O2, which entailed 10 min compared to energy- and time-intensive calcination and hydrothermal methods. HR-XPS revealed that O doping preferentially occurred through replacement of two coordinated N atoms of the triazine units. The effects of the ensuing electronic structure modulation were investigated with electrochemical tests where the metal-free catalyst displayed a specific capacitance of 262.5 F/g at a 1 A/g current density and a satisfactory capacitance retention of 73.17% at 6 A/g after 2000 cycles, which is comparable to those of various metals containing g-C3N4-based catalysts. The designed asymmetric supercapacitor device revealed a specific energy of 36.45 Wh/kg at a specific power of 2.5 kW/kg. The microwave-irradiated O-doped g-C3N4 showed an 8-fold increase in specific capacitance compared with bulk g-C3N4 in both CV and GCD analyses. The improved surface structure and O content enhanced the electrode–electrolyte contact area, thus making ion transfer highly efficient for EDLCs. These results also opened the potential of microwave-synthesized O-doped g-C3N4 as a base material for designing binary and ternary electrode materials.

Multistage Activation of Anthracite Coal-Based Activated Carbon for High-Performance Supercapacitor Applications

An anthracitic coal-derived activated porous carbon is proposed as a promising carbon electrode material for supercapacitor (SC) applications. The specific capacitance of this activated carbon SC electrode is related to the characteristics, such as specific surface area, pore size distribution, wettability, and conductivity. In the present work, a series of anthracite-based activated carbons (ABAC) were prepared via a multistage activation process and used as electrode materials for SCs. The multistage activation experiment was developed by exploring different activation temperatures, precursor/activating agent mass ratios, and process treating environments. The electrochemical performance of ABACs was evaluated in a three-electrode testing system. Multiple electrolytes were utilized, such as 1 M sulfuric acid (H2SO4) and 1 and 6 M potassium hydroxide (KOH) solutions. An optimum ABAC electrode was obtained, characterized by its largest wettability and superior conductivity, and achieved excellent electrochemical performance. The three-electrode system exhibited a specific capacitance of 288.52 and 260.30 F/g at 0.5 A/g in the 1 M H2SO4 and 6 M KOH electrolytes, respectively. It was found that moderate multistage activation temperatures are beneficial for the electrolyte uptake which enhances the specific capacitance. The high content of the oxygen functional groups on the activated carbon surface greatly improved its specific capacitance due to the increase in wettability. In the 1 M H2SO4 electrolyte, the working electrode exhibited better performance than in 1 M KOH because the ion diameter in the acidic electrolyte was more suitable for pore diffusion. The concentrated KOH electrolyte leads to an increase in specific capacitance due to increased ions being adsorbed by a certain number of the hydrophilic pores. Moreover, the specific capacitance of the optimum ABAC sample remained at 95.4% of the initial value after 1000 galvanostatic charge–discharge tests at 0.5 A/g, which is superior to the performance of SC grade commercial carbon.

Maximising 3D printed supercapacitor capacitance through convolutional neural network guided Bayesian optimisation

ABSTRACT A convolutional neural network (CNN) guided Bayesian optimisation framework is introduced to strategically maximise the surface to volume ratio of 3D printed lattice supercapacitors. We applied Bayesian optimisation on printing parameters to exploit regions where uniform and narrow lines are printed. A line shape classifying CNN model guided the optimiser’s search space to straight-line printed regions, minimising optimisation time and cost. An automatic scoring method allowed each iteration to be conducted within two minutes with accurate and precise measurements. The optimisation process has been demonstrated with graphene oxide (GO) and poly(3,4-ethylenedioxythiophene):polystyrene sulphonate (PEDOT:PSS) inks. The results were compared to the parameters that follow the conventional methodologies of direct ink writing (DIW) 3D printing. For each printed line of GO and PEDOT:PSS inks, irregularities decreased by 61.8% and 18.9% and average widths decreased by 39.0% and 28.6%. PEDOT:PSS lattice supercapacitor printed using optimised result showed a 151.0% increase in specific capacitance.

New low-cost, flow-through carbon electrodes characterized in brackish water

We propose a simple and low-cost flow-through electrode for electrochemical cells used for instance in capacitive desalination. We have coated macro-porous carbon fiber papers with various loads of carbon microporous particles to combine both a high surface area and an open structure for good fluid dynamics. In this first study, we restrict our investigation to the charging/discharging behavior, the identification of side reactions, and the effect of geometry on the diffusion of ions. The electrochemical performance was first investigated by cyclic voltammetry and galvanic charge–discharge techniques. The specific capacitance increases by three orders of magnitude upon adding the carbon particles. Then, electrochemical impedance spectroscopy revealed the presence of charge transfer phenomena and modification in the mass transport by the diffusion process for the coated electrode.Graphical abstractSEM image of the surface morphology of the cross section of CP/CFP/CP structure of the flow-through electrode.

Effect of surface modification of printed electrodes on the performance of supercapacitors

Fused Deposition Modeling (FDM), one of the 3D printing techniques is a low-cost method to print electrodes using conductive polymer composite filaments. In this study, electrochemical performance of EDLC supercapacitor assembled with 3D printed electrodes and two different electrolyte salts (KCl and (NH4)2SO4) in a PVA gel has been analysed. The electrodes are printed using graphene/carbon nanofiber incorporated PLA composite filaments. It is found that post-processing of printed electrodes is necessary to improve the electrochemical performance. Therefore, printed electrodes are sonicated in Dimethylformamide (DMF) solution, which modifies the electrode surface and increases the exposure of conducting materials with electrolyte. Effect of sonication time has been studied by exposing electrodes for 2 min and 10 min. The specific capacitance increases by two orders with 2 min sonication in both KCl and (NH4)2SO4. Also, increasing the sonication time to 10 min decreases the specific capacitance by 43 % for KCl and 23 % for (NH4)2SO4, respectively. This is due to loss of structural integrity of the printed electrode with prolonged sonication time. This study provides a foundation to design more efficient electrodes for EDLC supercapacitors.

Activation of nickel foam, as a current collector of a supercapacitor, by impact nickel plating: influence of treatment conditions

Nickel foam is widely used as a current lead/current collector and as the base of nickel hydroxide electrodes for hybrid supercapacitors. An investigation of the influence of activation conditions for a commercial sample of nickel foam produced by Linyi Gelon LIB Co Ltd (China) was carried out using the method of impact nickel plating. The morphology of activated and non-activated nickel foam samples was investigated by scanning electron microscopy. Activated and non-activated nickel foam samples were investigated by methods of cyclic voltammetry and galvanostatic charge-discharge cycling in the supercapacitor mode. It was shown that upon activation at i=1 A/dm2 and τ=10 min, a thin layer of porous nickel with incomplete coverage was formed. Activation with impact nickel at i=7 A/dm2 and τ=3 min revealed the formation of a nickel coating with a highly developed surface, on which local cracks were found as a result of the accumulation of internal stresses. Activation with impact nickel at i=1 A/dm2 and τ=10 min led to the formation of a coating with a highly developed surface, with significant peeling of the coating. Cyclic voltammetry showed high efficiency of impact nickel activation at i=7 A/dm2, τ=3 min, and i=20 A/dm2, τ=5 min. The specific current of the cathode peak increased 6.06–6.44 times with respect to the non-activated sample. The investigation of the activated samples' electrochemical characteristics by the galvanostatic cycling method showed that impact nickel activation at i=1 A/dm2 and τ=10 min was insufficient. It was found that at a discharge up to E=0 V, the maximum specific capacitance of 0.731 F/cm2 was obtained for samples activated by impact nickel at i=7 A/dm2 and τ=3 min. The increase in specific capacitance compared to the non-activated sample was 4.49 times. At full discharge, the highest electrochemical activity was found for nickel foam samples activated by impact nickel at i=20 A/dm2 and τ=5 min. The specific capacitance was 0.505 mA∙h/cm2, and it increased 9.02 times

Tailoring the charge storability of commercial activated carbon through surface treatment

Sustainability concerns in the electrochemical charge storage realm revitalized research on the electrochemical capacitors (ECs), or synonymously, supercapacitors (SCs), because of the renewability of their electrode materials and environmental benignity thereby, longer life cycle to improve materials circularity, and their inherent superior rate charging/discharging than batteries. As SCs store energy via the reversible adsorption of electrolyte ions on the electrode pores, maximizing the number of pores to accommodate the ions is the most desired way to improve the charge storability. In this regard, we report herewith a simple and facile approach for engineering the porosity of commercial activated carbon by refluxing it in nitric acid as a function of time; the BET surface area of the 72 h refluxed samples increased by 75 %. Charge storage properties of the modified electrodes are evaluated in a three-electrode system configuration in 1 M Na2SO4 electrolyte; a 75 % increase in the surface area led to an increase in specific capacitance over 110 % following a significant reduction in Warburg impedance. Besides, symmetric SC full cells were fabricated by varying the electrode mass between 3 and 14 mg·cm−2 in five steps. All the fabricated devices achieved a potential window of 1.8 V in 1 M Na2SO4. The highest mass loaded (∼14 mg·cm−2) device fabricated using the prepared material has delivered a maximum capacitance of ∼990 mF, the maximum areal capacitance of ∼494 mF·cm−2, an energy density of ∼13 mWh·cm−3, and a maximum power density of ∼2189 mW·cm−3. The device also maintained ∼97 % retention in capacitance with a remarkable coulombic efficiency of ∼97 % after 5000 cycles. The performance of the device is comparable with the commercial SCs used for low voltage DC hold-up applications such as embedded microprocessor systems. The procedure developed herewith supports easy recycling and reusing of the activation agent, and thereby reduces the release of toxic chemicals into the environment.

Electrochemical sensor based on green-synthesized iron oxide nanomaterial modified carbon paste electrode for Congo red electroanalysis and capacitance performance

ABSTRACT In this study, a facile protocol was used to convert non-valuable orange peels (OP) waste into a new sensing iron oxide orange-peel nanomaterial (FeOP). The presence of iron oxide nanoparticles in the modified OP was confirmed by physicochemical characterisations including Fourier-transform infrared spectroscopy, X-ray diffractometry, thermogravimetry, and scanning electron microscopy-energy dispersive X-ray. FeOP was used to modify a carbon paste electrode (CPE/FeOP) which displayed a significant increase in specific capacitance of 2939 F.g−1, two folds higher than that obtained with CPE at 10 m.s−1 in NaCl. The electroanalysis of Congo red (CR) in aqueous solutions using CPE/FeOP displayed detection limits of 2.8 × 10−7 mol.L−1 and 8.2 × 10−7 mol.L−1 respectively in deionised and spring waters, in the linear range of 5 to 55 µM. CPE/FeOP electrochemical sensor is therefore suitable for the determination of Congo red in wastewater.

Electrical properties of Mg2+ ion-conducting PEO: P(VdF-HFP) based solid blend polymer electrolytes

Mg2+ ion-conducting solid blend polymer electrolytes (SPEs) based on PEO: P(VdF-HFP) are prepared by solution casting technique using DMF as solvent. The X-ray diffraction analysis (XRD) confirms the decrease in crystalline phase of polymer electrolytes due to the addition of salt. The complex formation between polymers and salt is confirmed by Fourier transform infrared spectroscopy (FTIR) analysis. Morphological analysis shows the existence of interconnected micro-pores that enhances the mobility of Mg2+ ions. The polymer electrolyte (PEO:P(VdF-HFP):MgBr2)(90:10:15) has higher ionic conductivity of 3.90 × 10−4 S/cm at room temperature. For all solid blend polymer electrolytes, the total ionic transference number has been observed to be 0.98–0.99 range. The polymer electrolytes exhibit maximum electrochemical stability of 1.86 V. The cyclic voltammetry (CV) performance of the prepared EDLC reveals the increase in specific capacitance as the scan rate decreases. According to charge-discharge studies, the cyclic retention of the EDLC is maintained to be ∼84.2% even after 500 cycles.