Electrochemical Characterization Research Articles

Directly Fused Porphyrin-Tetracyanopentacenequinone Conjugates: Role of the Cross-Conjugated, Powerful Electron Acceptor in Promoting Highly Efficient Charge Separation.

Tetracyanopentacenequinone, a powerful electron acceptor, is fused directly to the porphyrin π-system to create a new class of donor-acceptor conjugates. Owing to the direct fusion and electron-deficient property of tetracyanopentacenequinone, strong intramolecular charge transfer both in the ground and excited states was witnessed. As a control, porphyrin fused with pentacenequinone was also investigated. Upon complete spectral and electrochemical characterization, the excited state properties were initially probed by time-dependent DFT studies, and the occurrence of electron transfer from different excited states was established. Free-energy calculations revealed higher exothermic electron transfer (> 600 mV) than the control pentacenequinone-porphyrin systems. Pump-probe studies covering broad spatial and temporal regions revealed efficient excited state charge separation. This was unlike the control pentacenequinone-porphyrin system, where slow charge separation was witnessed only in the case of the zinc derivatives but not the free-base ones. The lifetimes of the charge-separated states ranged between 30-500 ps depending on the solvent and metal ion in the porphyrin cavity. The significance of cross-conjugated tetracyanopentacenequinone fused directly to the porphyrin π system in promoting highly exothermic and efficient charge separation, irrespective of its cross conjugation, is borne out from this study.

Hydrothermally Synthesized Cobalt‐Doped NiO Nanoflakes: Enhanced Electrochemical Performance for High‐Performance Supercapacitors

This study examines cobalt‐doped nickel oxide (Co‐NiO) nanomaterials synthesized through a hydrothermal method, focusing on their potential as high‐performance electrodes for supercapacitors. By varying cobalt dopant concentrations (X = 0, 0.01, 0.05, 0.1), we aimed to enhance the electrochemical properties through strategic Co‐doping. The CoxNi1‐xO nanomaterials were characterized using several techniques, including X‐ray diffraction (XRD), UV‐visible spectroscopy, field emission scanning electron microscopy (FESEM), X‐ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), chronopotentiometry (CP), and electrochemical impedance spectroscopy (EIS). The analysis showed that Co‐doping preserved the NiO phase structure while significantly altering the morphology and electrochemical characteristics. The sample with (X = 0.1) achieved a specific capacitance of 880 F/g at a current density of 1 A/g, significantly outperforming the undoped NiO, which had a capacitance of 335 F/g. Additionally, the Co‐NiO demonstrated 83.3% capacitance retention after 1000 cycles at a current density of 10 A/g. These findings highlight the potential of Co‐NiO as an effective electrode material for supercapacitors.

Synthesis of O,F Co-Modified g-C3N4 for Photocatalytic H2 Evolution Activity Improvement and Corrosion Protection

Herein, we report the rational synthesis of porous g-C3N4 co-modified with oxygen (O) and fluorine (F) for the first time. Incorporating colloidal SiO2 during thermal polymerization introduces lattice oxygen, forming C–O bonds, while post-treatment with NH4·HF2 establishes C–F bonds. The dual incorporation of O and F elements extends visible light absorption and effectively promotes the separation and transport of photoexcited charge carriers. Consequently, the co-modified g-C3N4 (O,F-g-C3N4) achieves a 13.2-fold increase in H2 evolution rate compared to pristine g-C3N4. This synthesized O,F-g-C3N4 is then dispersed in waterborne polyurethane (WPU) to create an anti-corrosive coating for Q235 carbon steel substrates. Water resistance, mechanical property, and electrochemical characterization analyses reveal that the O,F-g-C3N4/WPU composite coating exhibits remarkable corrosion resistance with a high protection efficiency of 90.23%. This work offers a straightforward approach for developing highly efficient g-C3N4-based photocatalysts and corrosion-resistant coatings.

Anaerobic Catalyst Design for Alcohol Oxidation: Fine‐Tuning Copper/TEMPO with Bipyridine Proportions

In this study, we investigate the indirect electro‐oxidation of benzyl alcohol using the Copper/TEMPO catalytic system, which combines copper complexes with 2,2,6,6‐tetramethylpiperidin‐1‐oxyl (TEMPO) in an anaerobic medium. We reexamine the impact of bpy ligand proportions, exploring ratios of 1:1, 2:1, 3:1, and 4:1 on catalytic activity. Cyclic voltammetry and visible spectroscopy reveal distinct electrochemical characteristics and complex formations at different bpy ratios. Simulations uncover intricate energy equilibria involving ion coordination, varying with oxidation state and bpy proportion. Theoretical and experimental spectra align, supporting the proposed structures. The Brønsted base, triethylamine (TEA), essential in this anaerobic system, shows different voltammetric profiles with each ligand ratio, revealing key interactions with bpy complexes. In the presence of benzyl alcohol, the 1:1 and 2:1 ratios exhibit indirect catalytic activity, with the 2:1 ratio yielding significantly higher current densities. This establishes a new optimal condition where [Cu(bpy)₂]²⁺ formed in a 2:1 stoichiometry demonstrates superior activity with a lower redox potential, while maintaining labile coordination points for necessary interactions. Theoretical results also indicate weaker TEMPO coordination to [Cu(bpy)₂]²⁺.

Enhancing the Efficiency of Solar Cells Based on TiO2 and ZnO Photoanodes Through Copper Oxide: A Comparative Study Using Vitis labrusca Extract and N3 Ruthenium Dye

This study investigates the effects of varying CuO doping concentrations on the performance of titanium dioxide (TiO2)-based or zinc oxide (ZnO)-based dye-sensitized solar cells (DSSCs). TiO2 or ZnO mixed with CuO at different weight percentages (0–50 wt %) was employed as photoanodes in DSSCs, prepared via mechanical mixing. X-ray diffraction analysis revealed the structural changes, showing that as the CuO content increased in the hybrid, the CuO peaks (notably at 35.5° and 38.7°) became more prominent. Morphological and elemental characterizations were conducted using SEM and XRF, respectively. The solar cells were photosensitized by Vitis lasbrusca (V.L.) extract and N3 dye. The presence of anthocyanin molecules in the extracted V.L. was confirmed using UV-VIS and FTIR spectroscopy. The electrochemical characterization demonstrated optimal solar conversion efficiencies at a 20% doping level for both photosensitizers. Specifically, in the V.L. dye, TiO2-CuO achieved a conversion efficiency of 7.18%, and ZnO-CuO reached 5.77%. In the N3 dye, TiO2-CuO showed an efficiency of 11.34%, and ZnO-CuO, 9.55%. Notably, undoped photoanodes displayed a significantly lower photovoltaic performance: for V.L. dye, TiO2 showed 1.12% and ZnO 0.87%; for N3 dye, TiO2 showed 6.02% and ZnO 4.39%. Doping was therefore effective, yielding up to a seven-fold increase in performance in the case of V.L. with TiO2, compared to undoped DSSCs. The results demonstrate that using the hybrid photoanode led to a considerable increase in performance compared to using only TiO2 or ZnO photoanodes, highlighting the potential of DSSCs as sustainable energy sources.

Current‐Dependent Product Distribution and Reaction Mechanisms of Glycerol Electrooxidation on Nickel

AbstractThe Glycerol Electrooxidation Reaction (GEOR) is a promising alternative to oxygen evolution in electrochemical processes like hydrogen production and CO2 reduction. Although GEOR has attracted increasing attention, its oxidation kinetics in alkaline media are not well understood. In this study, electrochemical characterization and kinetic analysis were conducted using nickel foil as the electrocatalyst. Four galvanostatic conditions (1, 3, 5, and 10 mA cm−2) were evaluated to study product distribution. Increasing the current density from 3 to 5 mA cm−2 led to a fivefold decrease in formate production, indicating a shift in GEOR selectivity within the Oxygen Evolution Reaction (OER) region. At 10 mA cm−2, formate remained as major product, followed by glycolate and glycerate, while tartronate and oxalate production were significantly inhibited, reducing the total Faradaic Efficiency (FE) by half relative to 5 mA cm−2. Rate constants showed increased kinetics for glycerate, glycolate, oxalate, and tartronate as current increased, surpassing formate production at 5 mA cm−2. Spectroelectrochemical measurements revealed the reaction order for GEOR (αGEOR ~1) and OER (αOER ~3), showing that GEOR proceeds via a more efficient oxidative pathway, requiring interaction with just one NiOOH species, while OER involves three highly oxidized Ni‐species.

Silver Linings: Electrochemical Characterization of TiO2 Sol-Gel Coating on Ti6Al4V with AgNO3 for Antibacterial Excellence

This study aimed to synthesize TiO2 and silver-containing TiO2 layers on Ti6Al4V titanium alloy substrates, also known as titanium grade 5 (TiGr5), to provide corrosion resistance and antibacterial activity. The TiO2 layers were prepared through the sol-gel method and dip-coating technique. Silver introduction into the layers was performed in two different ways. One was the impregnation method by dipping the TiO2 layer-covered metal in aqueous AgNO3 solutions of various concentrations (TiO2/AgNO3), and the other was by direct introduction of AgNO3 into the precursor sol (Ag-TiO2). The two methods for incorporating AgNO3 into the coating matrix are novel, as they preserve silver in its ionic form rather than reducing it to metallic silver. The samples were put through electrochemical characterization, namely potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), and were tested in Hank’s solution, simulating a physiological environment. The behavior of the layers was monitored over time. Also, the thin layers’ thickness and adhesion to the substrate were determined. Microbiological evaluation of the Ag-doped coatings on glass substrates confirmed their significant bactericidal activity against Gram-negative Escherichia coli. Among the two types of coatings, the impregnated coatings demonstrated the most promising electrochemical performance, as evidenced by both EIS and potentiodynamic polarization analyses.

Polymer-modified screen-printed electrode-based electrochemical sensors for doxorubicin detection

In the last decade, intensive research has been performed in the field of analytical electrochemistry, seeking designs of electrochemical sensors capable of providing better analytical characteristics in terms of sensitivity, selectivity, reliability, ease of fabrication and use, and low cost, especially for pharmaceutical drug monitoring. Our research has primarily focused on developing screen-printed electrode-based sensors and their application as electrochemical platforms for drug determination and monitoring, specifically emphasizing their suitability for surface modification. A commercial screen-printed graphene electrode was used as the electrochemical sensing component, which was subsequently modified with polymers, such as polyvinylidene fluoride and chitosan. All studied electrodes were tested using a doxorubicin hydrochloride (DOX) solution with a concentration of 0.002 mol L-1 dissolved in 0.1 mol L-1 phosphate-buffered saline at pH 6.7. Cyclic voltammetry was used as an electrochemical characterization technique to gather data on all tested electrodes' electrochemical activity. The morphological characterization of the electrodes was done using scanning electron microscopy. The changes in the electrolyte during the electrochemical measurements were followed through ultraviolet-visible spectroscopy. The modified electrodes demonstrated a favorable electrochemical response to DOX and exhibited higher electrical conductivity than the commercial one. The characterization results indicated that the Ch-modified electrode exhibited excellent electrochemical conductivity and demonstrated strong electrochemical performance. The evaluations of this electrode comprised the definition of the lowest limit of detection and limit of quantification among the tested electrodes, with values of 9.822 and 32.741 µmol L-1, respectively, within a linear concentration range from 1.5 to 7.4 µmol L-1. Additionally, the electrodes showed excellent repeatability, stability, and reproducibility, confirming their suitability for sensitive DOX detection.

Vertically Aligned Ultrathin CoNi-LDH@NiS@MXCF Core-Shell Heterostructure for Flexible Supercapacitor Electrodes and Oxygen Evolution Reaction.

A multilayer core-shell heterostructure with CoNi-LDH as the core and NiS nanosheets as the shell is deposited on MXene-coated carbon nanofibers by electrospinning and electrochemical deposition. This unique structure not only combines highly conductive and hydrophilic one-dimensional carbon nanofibers but also exposes abundant two-dimensional reactive sites and multiple ion diffusion channels to maximize material utilization, enhance electron transfer kinetics, accelerate Faraday reaction, high capacitance and strong stability. The CNNS@MXCF electrode exhibits outstanding electrochemical characteristics, including a capacity of 1441.8 F g-1 at a current density of 1 A g-1 and excellent cycling stability. The CNNS@MXCF//VN@MXCF device shows a high energy density of 84.4 Wh kg-1 at 0.8 kW kg-1 power density, with nearly 92% capacitance retention after 10,000 cycles (30 A g-1). In addition, the oxygen evolution reaction (OER) shows a small overpotential of 128 mV, confirming the versatility and large potential of the materials and strategy.

Capacity fade-aware parameter identification of zero-dimensional model for vanadium redox flow batteries

This study proposes a framework for evaluating the electrochemical performance of a vanadium redox flow battery (VRFB) system. First, a numerical solver for redox flow battery is constructed to represent the multi-physics system through systems of ordinary differential equations, which describe the mass conservation of existing vanadium ions. The present numerical model is validated regarding the voltage by comparing its results with the experimental results of previous studies. Second, we identify the parameters in the governing equations using a genetic algorithm with the present numerical model. We select seven parameters by considering the physical meaning of each parameter related to the electrochemical performance. The voltage for the first charging/discharging cycle and capacity fade data are used to identify the selected parameters. The voltage and capacity fade estimated by the parameters identified using the numerical model align with the previous studies. Finally, we analyze the global sensitivity of the identified parameters in terms of the voltage and capacity fade using the total Sobol’ indices because the high sensitivity confirms that the identified parameters have reliable values. As expected, voltage- and capacity-related parameters show high total Sobol’ indices for the voltage and discharging capacity, respectively. Furthermore, we predict the performance of the VRFBs using the identified parameter set and numerical model during 30-cycle operations. Additionally, the performance is compared according to the current density and vanadium concentration in the electrolyte. The proposed framework can be used to evaluate the electrochemical characteristics of developed VRFBs by identifying parameters related to physical performance, such as voltage and capacity fade. Moreover, the identified parameters can be utilized to predict voltage and capacity performance, enabling the optimization of operating conditions and configurations of VRFBs.

Evolutionary trends and photothermal catalytic reduction performance of carbon dioxide by MOF-derived MnOx

Metal oxide catalysts derived from MOFs can inherit the excellent performance from their parent MOFs, possess abundant surface defects and high stability, and have attracted widespread interest in multiphase catalysis. In this study, we used Mn-MOF as a precursor and systematically investigated the evolution of MnOx catalysts by setting different calcination temperatures and times. XRD, SEM, TEM, Fourier transform infrared spectroscopy (FTIR), N2 adsorption–desorption analysis, XPS, H2-TPR, CO2-TPD, electrochemical characterization, and other methods were used to investigate the structural characteristics, microstructure, surface properties, and photoelectric properties of the catalysts. The catalytic performance of the catalysts was also investigated through photocatalytic carbon dioxide hydrogenation reduction tests. Research has shown that calcination temperature and time have a significant impact on the phase structure and surface properties of MnOx, and the physicochemical properties of derived MnOx can be controlled by controlling calcination temperature and time. Among them, MnOx-500 has a wider light absorption range, better electron transfer performance, richer oxygen vacancies, and excellent separation performance of photo generated charge carriers, resulting in higher photocatalytic CO2 hydrogenation and reduction performance. Its CO yield and selectivity reached 7420 μmol/g/h and above 99 %, respectively. This study provides valuable references for the preparation, optimization, and utilization in CO2 photothermal catalytic conversion of MnOx catalysts derived from MOFs.

Three-dimensional nanocomposites derived from combined metal organic frameworks doped with Ce, La, and Cu as a bifunctional electrocatalyst for supercapacitors and oxygen reduction reaction

Fabrication of a nanocomposite with a low-cost and efficient synthesis method instead of using electrocatalysts based on platinum metal has become one of the main challenges in energy storage devices and fuel cells. In this regard, a bifunctional electrocatalyst for supercapacitors and oxygen reduction reaction is fabricated and tested. The novelty of this study is the synthesis method and enhancement of the electrochemical characteristics of synthesized electrocatalysts. The core-shell method is used for the electrocatalyst's synthesis which uses Zeolitic Imidazolate Framework (ZIF)-8, ZIF-67, and Material Institute Lavoisiers (MIL)-101 for the fabrication of three types of electrocatalysts. In the following, to increase the characteristics such as conductivity and stability, doping of Copper (Cu), Cerium (Ce), and Lanthanum (La) are added to the nanocomposites. The Co@NC, CoZn@NC, and CoZn@FeNC prepared electrocatalysts are obtained from the pyrolyze process of La/ZIF-67, CeCu/ZIF-8@ La/ZIF-67, MIL-101@CeCu/ZIF-8/La/ZIF-67. The results indicated that the CoZn@NC electrocatalyst has the best performance in the oxygen reduction reaction (ORR) with an onset potential of 0.062 (V vs Ag/AgCl) and current density of −12.97 (mA/cm2) at a constant voltage of −1 V. Furthermore, the electron transfer number of CoZn@NC electrocatalyst for ORR was 3.64. The conducted Galvanostatic Charge-Discharge (GCD) tests demonstrated that the CoZn@NC electrode has the highest capacitance of 271.14 F/g. The outcomes showed that by the core-shell method, various properties of nanocomposites can be utilized to solve the weaknesses of catalysts by using proper metals. Moreover, the presence of Cu2+,Ce3+,La3+ improve the structural defects in the carbon matrix, the stability based on the chronoamperometry results, and the mass transfer. The study provides a perspective for future researches to fill the research gaps to obtain the new supercapacitors utilize on a large scale in the electronics industry.

A comparative analysis of different surface tribological and electrochemical properties of TiAlN, TiAlSiN, and CrAlN thin film coatings in seawater

Abstract To reveal the wear mechanisms of TiAlN, TiAlSiN, and CrAlN coatings in a seawater environment, the changes in frictional surfaces and the electrochemical characteristics of these coatings were compared and analyzed in this paper. The coatings were deposited on 316L stainless steel surfaces. Tribological tests were investigated using a ball-on-disk tribometer with Si3N4 ceramic balls as the counter material. Although the friction coefficient of 316L stainless steel was the lowest at 0.34, the order of wear rates was 316L stainless steel (7.38×10-5)>TiAlN(5.31×10-6)>TiAlSiN(4.23×10-6)>CrAlN(1.10×10-6) and the electrochemical protective efficiencies of TiAlSiN and CrAlN were both greater than 97%. Seawater penetrated through the grain boundaries of the TiAlN coating, which led to corrosion and delamination failure. Conversely, the grain refinement in TiAlSiN and CrAlN coatings can significantly slow down the penetration of seawater into the coating under frictional pressure, and the oxide lubricating layer formed during the friction process can become an effective barrier to isolate seawater. Therefore, mechanical wear was the main wear form of these two coatings. Additionally, among the oxides formed in the friction, Cr2O3 showed the strongest corrosion resistance, making the CrAlN coating exhibit superior wear resistance and the lowest wear rate in seawater.

Exploring the Structural, Spectroscopic, Antibacterial, and Electrochemical Characteristics of Silver-Doped Cadmium Oxide Nanoparticles

Exploring the Structural, Spectroscopic, Antibacterial, and Electrochemical Characteristics of Silver-Doped Cadmium Oxide Nanoparticles

Synthesis and nanoparticle formation of pyrazine, benzodithiophene (BDT) and fluorene containing conjugated polymer (P-PBF) and its biosensing performance toward catechol

The development of laccase-based biosensors, in particular, have attracted much interest due to their ability to detect highly toxic molecules in the environment. This article reports a novel biosensor for catechol detection that can be used to determine toxic molecules in the environment. For this purpose, a novel conjugated polymer (P-PBF) and conjugated polymer nanoparticles (P-PBFNPs) were synthesized and characterized, respectively. To our knowledge, research has yet to be done on conjugated polymer nanoparticle-based electrochemical biosensing platforms for catechol determination. The biosensor comprises a GE/P-PBF NPs/Lac electrode, constructed with P-PBF NPs deposited onto a bare graphite electrode followed by laccase (Lac) enzyme immobilization. While electrochemical characterization was performed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), surface characterization was performed by field emission scanning electron microscopy (FE-SEM). The biosensor exhibited high sensitivity (1.229 μA/μM.cm2), a good linear range (0.5–25 μM) and a low limit of detection (LOD) (0.49 μM). Moreover, the developed biosensor exhibited high selectivity in the presence of interfering analytes without any memory effects. The potential of the GE/P-PBF NPs/Lac electrode in tap water, green tea, synthetic urine and serum samples indicates the inspiring biosensing applications for monitoring environmental pollution.

Cobalt‐Based Materials in Supercapacitors and Batteries: A Review

Energy demand has become a persistent concern and high‐performance energy storage systems have increasingly undergone development. Supercapacitors and batteries pose great impact on energy storage and garner a great deal of attention from technologies and researchers alike. The performance of energy saving devices is primarily determined by the electrode material in terms of high specific capacitance, excellent conductivity, remarkable natural abundance, and unique electrochemical qualities, also large surface area. Cobalt (Co)‐based materials are unique electrode materials widely used in energy storage devices. Nevertheless, a combination of Co and ferrite materials such as nickel, zinc, and copper, or Co/nonferrite materials like metal–organic frameworks and layered double hydroxides has improved their ultimate efficiency. This review deals with energy storage applications of Co‐based materials, categorizing ferrites, their electrochemical characterization, performance, also design and manufacturing intended to supercapacitors and batteries applications. Summarizing the main outcomes of the literature on batteries and supercapacitors, energy storage systems comprising Co‐based materials combined with carbon nanotubes, graphene, silica, copper, zinc, nickel, cadmium, ferrous, and lanthanum are reviewed and discussed. Lithium‐ion batteries are investigated specifically, and perspectives on Co‐based ferrite development for future generations of supercapacitors and batteries are outlined.

Understanding the electrocatalytic role of magnesium doped bismuth copper titanate (BCTO) in oxygen evolution reaction

Designing high-efficiency electrocatalysts for water oxidation has become increasingly important in the catalysis field owing to its implications for renewable energy production and storage. The production of hydrogen (H2) from water is hampered by the very sluggish kinetics of the water-splitting process. Enhancement of effective oxygen evolution reaction (OER) electrocatalysts is also required to understand the primary barrier to OER. This article investigates the electrochemical activity of magnesium-doped bismuth copper titanate (Mg-BCTO) as an efficient catalyst for the OER in water electrolysis, a critical step in hydrogen production for sustainable energy. The synthesized materials, including various stoichiometries of Mg-doped BCTO, undergo thorough physical and electrochemical characterization using XRD, FT-IR, Raman, SEM, TEM, XPS, CV, EIS, and Tafel polarization analyses. Remarkably, Mg0.1 doped BCTO demonstrates superior performance, achieving a current density of 10 mA cm−2 at a very low overpotential (η10) of 265 mV and with a Tafel slope of 92 mV dec−1. This finding not only highlights the electrocatalytic efficiency of Mg doped BCTO but also positions it as a promising model for the development of highly active and stable water oxidizing catalysts, contributing to the advancement of clean energy technologies.

Enhanced super capacitance performance of V₂O₅·nH₂O/g-C₃N₄ nanocomposites: Synthesis, characterizations, and electrochemical properties

The primary problem addressed in this study is to enhance the performance of supercapacitor electrode materials by developing a cost-effective, and efficient synthesis method for nanocomposites with high capacitance. Hence, in this study, we report the synthesis of V2O5·nH2O/g-C3N4 nanocomposites using a cost-effective hydrothermal method, resulting in four distinct samples: pristine V2O5·nH2O nanoribbons (VO) and three composites with varying amounts of g-C3N4 (10, 20, and 30 mg), labelled as VCN1, VCN2, and VCN3. Structural, morphological, optical, and electrochemical characterizations were conducted to assess their potential as supercapacitor electrode materials. Electrochemical analysis, including cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD), confirmed pseudocapacitance behavior in all samples. VCN1, containing 10 mg of g-C3N4 in V2O5·nH2O matrix, exhibited the highest specific capacitance of 230 F/g at a scan rate of 10 mV/s in a 3M KOH electrolyte. This enhancement in capacitance is attributed to the added g-C3N4, which increases active sites, as confirmed by Electrochemically Active Surface Area (EASA) measurements. Additionally, electrochemical impedance spectroscopy (EIS) supported VCN1's superior performance, identifying it as a promising, cost-effective electrode material for super capacitor applications.

High-strength polyvinyl alcohol/gelatin/LiCl dual-network conductive hydrogel for multifunctional sensors and supercapacitors

The synthesis of conductive hydrogels with high mechanical strength, toughness, optimal fracture growth rate and the capability to detect diverse human body movements poses a significant challenge in the realm of flexible electronics. In this study, a one-pot technique utilized effectively to fabricate conductive materials by doping LiCl into a mixture of polyvinyl alcohol (PVA) and gelatin. The PVA/gelatin/LiCl0.3(PGL) conductive hydrogel demonstrates exceptional robustness, flexibility, and resistance to deformation, enabling the monitoring of various physiological signals such as temperature and humidity. Additionally, the PGL demonstrates exceptional elongation properties (up to 1111.32 %), high lifting capacity (up to 25 kg), resistance to deformation, and sustained stability of peak signals even after 300 cycles at 50 % strain. The hydrogel electrolyte exhibits a conductivity of 2.114 S/m at 25 °C and a specific capacitance of up to 48.75 F/g, along with favorable mechanical and electrochemical characteristics. These findings suggest that the PVA/gelatin/LiCl0.3 hydrogel supercapacitor (PGLSC) conductive hydrogel shows significant potential for integration into flexible electronics and wearable technology devices.

Polyaniline@MoS2: An organic and inorganic hybrid framework for asymmetric supercapacitor applications

The polyaniline and MoS2-based organic and inorganic hybrid composite have been synthesized by varying MoS2 concentrations ranging from 1 to 10 wt% and their charge storage performances were analyzed in a three-electrode and in asymmetric cell configuration to understand their electrochemical characteristics. The electrochemical characteristics of the as-prepared electrodes such as cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy were studied in 1 M H2SO4 electrolyte. Among the prepared compositions PANI@MoS2 (5 wt%) electrode showed a high specific capacity of 148.6 F g−1 at 0.5 A g−1 among the prepared compositions. Further, the asymmetric hybrid pouch cell was fabricated where PANI@MoS2 and activated carbon were used as a positive and negative electrode, respectively. The 2 × 2 cm2 asymmetric cell (AC||PANI@MoS2(5 wt%) delivered a specific energy of 32 Wh kg−1 at a specific power of 3.2 kW kg−1 in the PVA-H2SO4 hydrogel electrolyte. This specific energy is two-fold higher than the AC||PANI asymmetric cell where the specific energy and specific power are about 18.66 Wh kg−1 and 3.2 kW kg−1, respectively. The cycle stability of the AC||PANI@MoS2 (5 wt%) was also performed at 2 A g−1 and the cell showed capacitance retention of about 99.27% after 13,000 cycles. The cell performances at different bending angles were analyzed to ensure the flexible nature of the pouch cell. Thus, the proposed organic and inorganic hybrid composite electrode is believed to be a potential electrode material for supercapacitor application in an acidic electrolyte medium.