Bulk-interface synergetic engineering of nanocomposite air electrode toward durable and high-performance solid oxide cells

Fabrication and electrochemical evaluation of polythiophene-polypyrrole-RuO2 ternary nanocomposite electrodes for high performance supercapacitor applications

Graphene-integrated bismuth ferrite nanocomposites electrode material for high-performance supercapacitors with enhanced energy density and stability

Enhanced electrochemical performance of SrO-CNTs nanocomposite electrode for supercapacitor application

Abstract In this study we have investigate the systematic synthesis, characterization, and electrochemical study of Ti3C2Tx/NiFe2O4 nanocomposite electrodes for high-performance Quasi-Solid-State supercapacitor applications. The study explores the synergistic effects arising from the strategic integration of two-dimensional Ti3C2Tx MXenes nanosheets with pseudocapacitive NiFe2O4 nanoparticles to overcome the individual limitations of each component while maximizing their complementary advantages. Through systematic variation of NiFe2O4 loading percentages (5%, 20%, 50%, and 80%), the optimal composition was identified as Ti3C2TxNiFe2O4@20% (MNFO20), which demonstrated exceptional electrochemical performance characteristics. Comprehensive electrochemical characterization employing cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy revealed that the MNFO20 nanocomposite achieved a remarkable specific capacitance of 242 F/g at 10 mV/s, as compared to pristine MXenes (68 F/g). The nanocomposite exhibited superior energy density of 57.76 Wh/kg and power density of 799.84 W/kg. Mechanistic analysis revealed that the enhanced performance originates from synergistic effects including the formation of efficient electron transport networks, complementary charge storage mechanisms combining electrical double-layer capacitance and pseudocapacitance, prevention of MXenes layer restacking, and improved electrolyte accessibility. The charge transfer resistance was dramatically reduced from 2.25 Ω for pristine MXenes to 0.14 Ω for the MNFO20 composite, demonstrating significantly improved charge transfer kinetics. It also maintains 86.2% of its initial capacity over 2000 cycles. These findings establish Ti3C2Tx/NiFe2O4 nanocomposites as promising electrode materials for next-generation energy storage devices requiring both high energy density and rapid power delivery capabilities.

Accurate electrochemical quantification of niclosamide (NA) remains challenging due to its limited aqueous solubility, sluggish electron-transfer kinetics, and the inherently complex multi-electron nitro-reduction pathway. In this work, a β-cyclodextrin/acetylene black composite electrode (β-CD@AB/GCE) is developed to overcome these limitations through the combined benefits of a highly conductive porous carbon network and the strong host–guest inclusion capability of β-cyclodextrin. The composite architecture enhances interfacial preconcentration of NA, promotes favorable molecular orientation for electron transfer, and improves the efficiency of mass and charge transport throughout the porous film. To elucidate the mechanistic origins of these enhancements, a fully coupled multiphysics framework was constructed in COMSOL, integrating charge conservation, mass transport of diluted species, Butler–Volmer kinetics, and Langmuir adsorption dynamics. The model accurately captures experimentally observed behaviors (including potential gradients, ohmic polarization, concentration depletion, and the transition between diffusion-controlled and adsorption-controlled regimes) with excellent agreement between simulations and voltammetric measurements (RMSE = 0.078). Both modeling and experiments reveal that β-CD-mediated enrichment increases interfacial NA concentration by more than an order of magnitude, while the optimized porous microstructure ensures uniform overpotential distribution and efficient charge transfer. The resulting β-CD@AB/GCE sensor exhibits high sensitivity (3.675 µA µM−1), a broad linear range, and an ultralow detection limit of 0.019 µM. The proposed electrochemical sensing platform, investigated entirely through COMSOL Multiphysics simulations, demonstrates a linear electrochemical response toward the target analyte within the concentration range of 0.05–10 µM. The simulated calibration curve yields the equation Ip = 0.192C + 0.015 (R2 = 0.996), corresponding to a detection limit of 0.02 µM. This broad and well-defined linear range confirms the strong quantitative capability of the simulated sensor design. These findings establish a mechanistic foundation for the rational design of β-cyclodextrin-functionalized carbon electrodes and provide a broadly applicable strategy for next-generation electrochemical sensors targeting hydrophobic nitroaromatic pharmaceuticals and related bioactive species.

Dental caries, with a global prevalence of 29%, represents a major public health challenge. Traditional diagnostic methods often delay intervention, leading to irreversible tooth damage. In this study, we present a saliva-based electrochemical sensing platform for the early prediction of dental caries through the simultaneous detection of three key biomarkers: Streptococcus mutans, Ca2+, and pH. A nanocomposite electrode, constructed from Prussian blue, metal-organic framework, polypyrrole, and carboxylated multi-walled carbon nanotubes, provided a highly active electrochemical surface with reduced interfacial resistance and an enhanced electron transfer rate. For S. mutans detection, dual-recognition elements comprising a competence-stimulating peptide and an S. mutans-imprinted polymer were used to ensure selective binding. Ca2+ and pH were detected using a Ca2+ ion-selective membrane and a doped polyaniline film, respectively. The platform demonstrated detection ranges of 101-108CFUmL-1 for S. mutans, 0.01-100mM for Ca2+, and pH 4.0-8.0, with excellent resistance to salivary interference, high reproducibility, and long-term stability. Testing on clinical samples confirmed the platform's ability to accurately distinguish caries status, highlighting its potential as a non-invasive and portable diagnostic tool for early dental caries prediction.

Synergistic enhancement of sustainable energy storage through a novel hydroxyapatite/nickel tungstate nanocomposite electrode

Flexible polyvinyl alcohol-based lanthanum nickelate@reduced graphene oxide nanocomposite electrodes for hybrid supercapacitors

Copper bismuth oxide nanoparticles decorated on g-C3N4 nanocomposite electrode for highly efficient supercapacitor applications

A comprehensive 2D finite-element model based on COMSOL Multiphysics has been developed to investigate the pH-dependent electrochemical performance of reduced graphene oxide/copper–cuprous oxide (rGO/Cu–Cu2O) nanocomposite electrodes stabilised by a NaOH-treated porous polyvinyl alcohol/polyethylene oxide (PVA/PEO) film for non-enzymatic glucose detection in alkaline media (pH 9.12–14.09). The model couples the Nernst equation for open-circuit potential, Butler–Volmer kinetics for glucose oxidation via the Cu(ii)/Cu(iii) redox shuttle, Nernst–Planck transport for glucose and OH−, and charge conservation across the porous polymer layer. Optimal electrocatalytic activity is achieved at pH 13.03, delivering an ultrahigh sensitivity of 853.19 µA mM−1 cm−2, a stable open-circuit potential of 0.653 V (vs. Ag/AgCl), a linear range up to 10.2 mM, and a rapid response time of 2.08 s. Systematic parametric analysis reveals that decreasing PVA/PEO film thickness to ∼300 nm, reducing Cu–Cu2O nanoparticle diameter below 30 nm, and increasing rGO conductivity above 1400 S m−1 dramatically enhance both sensitivity and response speed by improving ion accessibility and electron-transfer efficiency. Model predictions are rigorously validated against experimental electrochemical impedance spectroscopy data (RMSE = 0.08), confirming predictive accuracy. The work elucidates fundamental pH–structure–performance relationships and provides quantitative design guidelines for robust, cost-effective, enzyme-free glucose sensors suitable for diabetes monitoring and wearable diagnostic platforms.

Ionic polymer-metal composites consist of an ion-conducting polymer-gel membrane sandwiched between two flexible electrodes, representing a class of soft electroactive materials capable of large deformation under low voltage. The gel membrane, swollen with solvent, facilitates ion migration under an electric field, enabling actuation. Tailoring the interfacial architecture between the electrode and the polymer-gel membrane is pivotal for advancing high-performance IPMC actuators. This study presents a comparative investigation of three core-shell nanocomposite electrodes, fabricated via in situ polymerization, for IPMC applications. Among these, the polyaniline-coated multi-walled carbon nanotube composite exhibits a deliberately designed hierarchical structure, with a specific surface area of 32.345 m2·g-1 and a conductive doped polyaniline shell, as confirmed through XPS analysis. This optimized interface enables superior charge storage and transport, endowing the corresponding electrode with a specific capacitance of 40.28 mF·cm-2 at 100 mV·s-1-3.2 times greater than that of conventional silver-based electrodes-along with a reduced sheet resistance. When integrated with a Nafion ion-gel membrane, the PANI@MWCNT electrode achieves a 67% increase in force density and a larger displacement output compared to standard devices, directly correlated with its enhanced electrical and electrochemical properties. This work highlights the critical role of core-shell interfacial engineering in governing electromechanical performance at the electrode-gel interface and offers a practical design strategy for developing high-performance, cost-effective IPMC actuators for soft robotics, flexible electronics, and related applications.

This research introduces a sustainable strategy for supercapacitor fabrication by utilizing waste-dry cell battery-derived materials to simultaneously meet energy-storage demands and mitigate environmental concerns. Cobalt-doped zinc ferrite (Co0.5Zn0.5Fe2O4) (CZF) of spinel structure was synthesized using a hydrothermal method, and subsequently, 2D reduced graphene oxide (rGO) was derived from waste dry-cell batteries. The integration of the CZF/rGO nanocomposite was achieved via a straightforward sonication process, which was confirmed by a series of spectroscopic analyses, viz., FTIR, SEM, EDX, XRD, XPS, TEM and BET analyses. The SEM observations together with BET surface area analysis revealed that the nanocomposite possesses a porous structure, which can effectively promote electrolyte ion transport while providing a large surface area for enhanced charge storage. The electrochemical behavior was investigated in a 2 M KOH electrolyte using a three-electrode system, where a glassy carbon electrode (GCE) served as the working electrode, through CV, GCD, and EIS. The CZF/rGO nanocomposite electrode exhibits a specific capacitance of 91 F g−1 (0.13 F cm−2) at 10 A g−1, while maintaining a relatively low internal resistance of 1.9 Ω. Moreover, the assembled asymmetric device exhibits an energy density of 3.99 Wh kg−1 at a power density of 450 W kg−1. The device also shows good cycling stability, retaining 84.1% of the initial capacitance after 1000 cycles. These improvements arise from the combined contribution of CZF and rGO, providing abundant active sites, improved charge transport, and a high accessible surface area. Overall, the findings demonstrate that materials derived from waste can serve as promising and sustainable candidates for energy storage, with potential for practical supercapacitor devices demanding stable, fast-charging, and environmentally friendly electrodes.

A dual chamber microbial fuel cells was developed using biomass derived reduced graphene oxide (E-rGO) synthesized from Ensete ventricosum corm waste as an anode material for simultaneous bioelectricity generation and heavy metal remediation. To enhance electrochemical performance, an E-rGO/Fe3O4/PANI NC anode was fabricated and evaluated for the removal of Cr (VI) and Pb (II) from wastewater. Incorporation of Fe3O4 NP and polyaniline improved electrical conductivity, surface characteristics, and interfacial charge transfer properties. Structural, morphological, optical, and thermal properties of the materials were characterized using UV-vis, SEM, XRD, FTIR, Raman spectroscopy, and TGA, while electrochemical behavior was examined by cyclic voltammetry and electrochemical impedance spectroscopy. The E-rGO/Fe3O4/PANI anode achieved Cr (VI) and Pb (II) removal efficiencies of 88% and 86%, respectively, compared with 74% and 68% for pristine E-rGO. The E-rGO/Fe3O4/PANI nanocomposite electrode also generated a maximum power density of 65 mW m−2 and a current density of 1312 mA m−2, representing a significant improvement over the E-rGO anode (8.55 mW m−2 and 612 mA m−2 under identical operating conditions. While the power density is moderate compared with highly optimized laboratory scale MFC systems, the results demonstrate enhanced performance in a system designed for concurrent wastewater treatment and energy recovery. These findings indicate that biomass derived graphene based nanocomposites can serve as sustainable and effective electrode materials for integrated heavy metal remediation and bioenergy generation in microbial fuel cell systems.

The persistent toxicity and bioaccumulation of lead ions (Pb2+) in aquatic systems pose significant risks to environmental and public health, necessitating the development of reliable trace-level detection strategies. In this work, a high-performance electrochemical sensor is fabricated through the rational design of a two-dimensional nanocomposite comprising hydrofluoric acid-etched Ti3C2TxMXene and vanadium disulfide (VS2). The integration leverages the high electrical conductivity and surface functionalization capacity of Ti3C2Txwith the intrinsic redox activity and layered structure of VS2, resulting in a composition with accelerated electron transfer rates and improved surface adsorption for Pb2+ions. The Ti3C2Tx@VS2composite, functionalized on a glassy carbon electrode via a simple drop-casting approach, exhibits a broad linear detection window spanning 1µg l-1to 100 mg l-1(1 ppb to 100 ppm) and an ultralow detection limit of 0.13µg l-1(ppb), enabling precise monitoring much below regulatory thresholds. The sensor demonstrates excellent repeatability (RSD < 1.02%), high selectivity against common interfering ions. This study highlights the functional synergy of Ti3C2Tx@VS2interfaces and establishes a promising route for scalable, high-fidelity electrochemical sensing of heavy metal pollutants in complex environmental matrices.

Investigating a nanocomposite electrode composed of carbon nanotubes/graphene oxide and titanium dioxide (CNT/GO/TiO2) for supercapacitors application

Facile synthesis and electrochemical behavior of CoWO4@C@MnOx nanocomposite electrode material as a high-performance supercapacitor

Advanced Bi2O3/ZrO2/PVA nanocomposite electrode for sensitive and selective hydrazine detection

Poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) is widely available as an aqueous dispersion of colloidal particles; however, it has several technical limitations, including poor solubility in water and organic solvents, which hinder processability and device performance. This study synthesized a novel PEDOT derivative bearing a methylsulfonic acid moiety, poly[(2,3-dihydrothieno[3,4- b ][1,4]dioxin-2-yl)methylsulfonic acid] (PEDOT-SO 3 H), which is highly soluble in aqueous and organic media. The performance of PEDOT-SO 3 H was investigated by fabricating nanocomposite electrodes and actuators composed of highly conductive single-walled carbon nanotubes synthesized via the super-growth (SG) method (SG-SWCNTs), PEDOT-SO 3 H, and one of two ionic liquids (ILs). Thus, the underlying mechanisms were observed and determined to be a combination of electric double-layer and faradaic capacitance. The electromechanical and electrochemical properties of the SG-SWCNT/PEDOT-SO 3 H/IL composites were compared with those of previously developed SG-SWCNT/PEDOT:PSS/IL and SG-SWCNT/IL composites. The PEDOT-SO 3 H-based electrode demonstrated significantly lower volume and surface resistivity and a higher specific capacitance than the PEDOT:PSS-based electrode. Furthermore, the PEDOT-SO 3 H-based actuators showed greater maximum strain than PEDOT:PSS-based actuators. These results indicate that PEDOT-SO 3 H can improve the performance of actuators. The frequency-dependent strain behavior was accurately predicted using a kinetic model based on double-layer charging, which confirmed that the actuator operated via a combination of double-layer and faradaic capacitance mechanisms. In conclusion, PEDOT-SO 3 H offers superior conductivity, capacitance, and strain performance compared with PEDOT:PSS, making it a promising material for next-generation soft actuators, particularly in biomedical and flexible electronic applications. • This study synthesized PEDOT-SO 3 H, which is soluble in aqueous and organic media • SG-SWCNT/PEDOT-SO 3 H/IL electrodes and actuators were fabricated successfully • Both electric double-layer and faradaic capacitance mechanisms were observed • The electrodes and actuators outperformed those using other PEDOT-derivatives • The frequency–strain behavior was predicted by a double-layer charging-based model

Engineering a ternary NiCo2O4@mesoporous carbon-reduced graphene oxide nanocomposite electrode for improved lithium and sodium-ion storage