Search Results (2,502)

Biomass-derived porous carbons are promising supercapacitor electrodes, but their electrochemical performance is often limited by the trade-off between activation-induced pore formation and heteroatom retention. In this work, algae biomass was used as an intrinsic N/O/S-containing precursor to prepare self-nitrogen-doped hierarchical porous carbon by pre-carbonization followed by controlled KOH activation. A temperature-, dosage- and time-dependent sample library was constructed to correlate activation conditions with textural properties, nitrogen configuration, wettability, charge-transfer resistance and electrochemical behavior. The optimized AHPC-850 sample exhibits a BET surface area of 1486 m² g⁻¹, a total pore volume of $0.96$ cm³ g⁻¹, a retained surface nitrogen content of 2.91 at.%, and a charge-transfer resistance of $0.41$$\Omega$. In a three-electrode configuration, AHPC-850 delivers 386 F g⁻¹ at 1 A g⁻¹ and retains 62.4% of its capacitance at 20 A g⁻¹. During 10,000 cycles at 10 A g⁻¹, the electrode maintains 96.3% capacitance retention with a stable coulombic efficiency above 98.8%. A symmetric aqueous device based on AHPC-850 achieves an energy density of $24.8$ Wh kg⁻¹ at 250 W kg⁻¹. These results indicate that algae-derived carbon can be improved by balancing pore accessibility, nitrogen retention and transport resistance rather than by maximizing surface area alone. Full article

Electrochemical nitrate reduction reaction (eNO₃RR) has emerged as a promising alternative to the energy-intensive and carbon-intensive Haber–Bosch process for green ammonia synthesis. However, the intrinsic complexity of the eight-electron transfer pathway and inevitable competing side reactions limit the activity and selectivity of eNO₃RR. Maximizing the utilization of active sites and ensuring structural stability in electrocatalysts are essential for promoting surface proton-coupled electron transfer and improving Faradaic efficiency. Herein, we present a copper metal–organic framework (Cu-MOF)-derived electrocatalyst synthesized via in situ electrosynthesis on copper foam, using cetyltrimethylammonium bromide (CTAB) as a structure-directing agent, followed by electroreduction to produce a self-supported, nano-dendritic structure. This three-dimensional architecture exposes abundant active sites and facilitates electron transport, enabling efficient nitrate-to-ammonia conversion. The optimized CTAB-assisted electrode achieves an ammonia yield of 14.33 ± 0.61 mg h⁻¹ cm⁻² with a Faradaic efficiency of 90.95 ± 2.28% at −1.7 V versus Ag/AgCl. This study introduces a versatile design strategy for copper-based electrocatalysts that integrates structural stability with high activity, offering a sustainable approach for both ammonia production and nitrate remediation. Full article

A new method is described for the determination of vanadium using adsorptive stripping voltammetry of V(V) complexed with cupferron at a CNTs/SGC electrode modified with a lead film. The CNTs/SGC electrode is based on carbon nanomaterials such as carbon nanotubes and spherical glassy carbon, which form the foundation of modern sensor technology. Optimal conditions of adsorptive voltammetric measurement were found to be modification/accumulation potential and time of −1.6 V and 60 s, respectively, and supporting electrolyte of 0.2 mol/L NaAc–HAc buffer (pH 5.3) containing 0.3 mmol/L cupferron and 0.15 mmol/L Pb(II). The response of the system was found to be linear in a range of V(V) concentrations from 0.25 nmol/L to 10 nmol/L. The detection limit was found to be 0.08 nmol/L. The selectivity of the procedure was determined by analysing the effect of other interfering ions on the vanadium analytical signal. The method was successfully validated by analysing natural environmental waters. Full article

The development of low-cost, environmentally friendly, and electrochemically stable electrode materials remains a significant challenge for supercapacitors. In the present study, composite materials based on a montmorillonite K10 clay support were synthesized and characterized. Coconut shell-derived activated carbon, manganese dioxide (MnO₂), and/or activated carbon (YP-80F) modified with silver nanoparticles were utilized as functional additives to the clay matrix. The aim of this work is to enhance the specific capacitance and electrochemical stability of the materials through a synergistic effect between these individual components. The novelty of this study lies in the integration of montmorillonite K10-based nanocomposites with an ion-exchange hydrogel membrane and in the investigation of the synergistic effects of different functional additives on the electrochemical performance of supercapacitors. The electrodes were fabricated using a casting method, while a commercial membrane, pre-soaked in a sodium sulfate solution, was employed as both separator and electrolyte. The membrane functions as an ion-exchange hydrogel, contributing to high ionic conductivity and reduced interfacial resistance. The electrochemical results indicate that the presence of additives significantly improves electron transport within the system, while the K10 clay support acts as a stable structural framework. The obtained results demonstrate the potential of clay-based nanocomposites integrated into gel-polymer systems for the development of efficient, low-cost, and environmentally friendly next-generation supercapacitors. Full article

Silicon anodes hold great promise in high-energy lithium-ion batteries (LIBs) owing to their ultrahigh theoretical specific capacity, appropriate operating voltage, and low costs. However, the drastic volume expansion, inferior electronic conductivity, and unstable solid electrolyte interphase of Si anodes severely restrict their practical application. Herein, a nest-shaped microporous silicon (NMPSi) is rationally designed via acid–base co-etching and then synergistically regulated by surface thin-film carbon coating and ZIF-67-derived hard carbon nanotemplate (NMPSi@THC) by an in situ liquid-phase coating strategy. The constructed unique architecture is capable of buffering the huge volume expansion of inner NMPSi during cycling and constructing an optimized electron/ion transport network, thereby stabilizing the SEI film and preserving the electrode’s structural integrity. When it is evaluated as a LIB anode, the NMPSi@THC exhibits typically improved initial coulombic efficiency (ICE) and outstanding long-life cyclic stability (622.7 mAh g⁻¹ after 300 cycles at 1 A g⁻¹ and 2 mg cm⁻²). Furthermore, the NMPSi@THC//LiFePO₄ full cell delivers an ultrahigh ICE of 94% and a capacity retention rate of 86%, demonstrating its practical application potential. Compared with most recently reported Si anodes, this report delivers better cycling stability and maintains more intact electrode structure under relatively high current density and areal mass loading in half/full cells after long-term cycling. This research offers a convenient and scalable route to fabricate highly stable microporous Si anodes toward high-energy and long-lifespan LIBs. Full article

Maintaining a conductive network is essential for achieving high energy density and long-term reliability in lithium-ion batteries. However, its stability is often compromised by structural non-uniformity, and under high-voltage operation, by the oxidative degradation of carbon-based conductive additives. To address these issues, we propose a composite cathode design that combines multi-component electrophoretic deposition (EPD) with a chemically stable Ti₄O₇ conductive oxide. The EPD conditions were systematically investigated, and an applied voltage of 100 V was identified as the standard voltage for controlling electrode loading while avoiding cracking and delamination under severe deposition conditions. The electrochemical performance of the EPD-derived electrodes depended strongly on the Ti₄O₇ content in the initial EPD suspension. Ti-0 and Ti-1, prepared from suspensions containing 0 and 1 wt% Ti₄O₇, respectively, maintained stable capacity delivery over a wide loading range, with areal capacities in good agreement with the theoretical values. In contrast, Ti-5, prepared from a suspension containing 5 wt% Ti₄O₇, exhibited significant capacity degradation and failed under high-loading conditions. High-voltage cycling over 50 cycles and impedance analysis further showed that Ti-1 exhibited better cycling behavior than Ti-0, with less pronounced resistance growth, whereas Ti-5 displayed poor cycling performance. These results suggest that multi-component EPD with an appropriate amount of Ti₄O₇ can provide a balanced hybrid conductive network for improving the relative high-voltage cycling behavior of cathodes within the tested condition. Full article

Thorium (Th) is increasingly considered a promising fertile material for sustainable nuclear energy—which is not fissile itself, but convertible to fissile ²³³U—particularly as a by-product of rare earth element (REE) processing. This study develops a parametric techno-economic assessment (TEA) framework synthesizing published data from China, Russia, the USA, India, and Europe to establish the methodological foundation for evaluating thorium recovery economics from monazite ores and REE tailings under Central Asian conditions. Monazite typically contains 4–12% ThO₂, while tailings contain 0.1–3%, making secondary resources attractive for future recovery strategies. Particular attention is given to integration with uranium tailings and the application of advanced materials such as nanocomposite sorbents and carbon-based electrodes. Reported production costs of ThO₂ range from 50 to 500 USD/kg depending on process scale, feedstock quality, and co-production of REEs. The reviewed studies consistently show that coupling thorium recovery with REE processing improves economic feasibility. Modern approaches, including hybrid technologies and electrosorption systems, may reduce operational costs and improve process efficiency. Despite challenges related to capital investment, market uncertainty, and radioactive waste management, thorium continues to attract growing interest as a potential component of future nuclear fuel cycles and advanced reactor systems, including small modular reactors. To the best of the authors’ knowledge, this is the first parametric TEA framework structured around Central Asian conditions, combining literature-derived regional data, scenario-based process economics, and Monte Carlo sensitivity analysis within a single discounted cash flow structure. Full article

Gold is considered the most widely used surface for the development of aptamer-based layers. However, its high cost, laborious surface-cleaning protocols, and susceptibility of receptor layers to degradation in complex samples, including biological fluids, enforce the search for alternative transducers. One solution is the application of carbon materials, which are inexpensive and allow for the use of a wide potential range when electrochemical measurements are performed. Herein, we present studies on the elaboration of aptamer receptor layers formed on carbon macroelectrodes. To achieve this, a one-step procedure for aptamer molecules containing a pyrene or anthracene group at the 5′ end was used, with immobilization via adsorption facilitated by Π–Π interactions between the anchor group and the carbon surface. It was evidenced that using anthracene-modified aptamer and sodium anthraquinone-2-sulfonic acid (AQMS) redox indicator enabled the detection of a model analyte–vancomycin below the millimolar concentration range. It was also revealed that vancomycin can be successfully detected in serum samples, and the aptasensor exhibits good selectivity towards vancomycin. The latter was observed by comparison of responses in PBS containing solely vancomycin and a solution spiked with vancomycin and a mixture of antibiotics. Full article

The practical application of Li–O₂ batteries is severely hindered by parasitic reactions on the cathode side, which generally lead to large charging over-potentials and degraded cyclic performance. To address this issue, it is essential to integrate high-efficiency catalysts into conventional carbon-based electrodes. Herein, we report a novel La_0.85Ca_0.15Cr_0.85O₃@Ru (LCC@R) hybrid catalyst with an ultralow Ru loading (6.55 wt.%), synthesized via a facile sol-gel combined with in-situ reduction-exsolution method. Mono-dispersed and ultrafine Ru nanocrystals (2–5 nm) are uniformly anchored on the LCC substrate and serve as the catalytically active sites. The Li–O₂ battery with the LCC@R catalyst exhibits a low charge potential of 3.75 V at a current density of 50 mAg⁻¹ with limited capacity of 500 mAhg⁻¹. Impressive cyclic stabilities of up to 80 cycles (at 1000 mAhg⁻¹) and 15 cycles (at 2000 mAhg⁻¹) are achieved. Moreover, a large specific capacity of 8630 mAhg⁻¹ is delivered at 50 mAg⁻¹. Mechanistic studies reveal that the intermediate discharge product LiO₂ can be absorbed on LCC@R, thereby inhibiting the parasitic reactions induced by LiO₂ attack on carbon. The as-prepared LCC@R hybrid material is a promising cathode catalyst for constructing long-cycle-life and low-over-potential Li–O₂ batteries. Full article

Aiming to develop high-performance flexible electrode materials for dielectric elastomer actuation systems applied to micro-crawling robots, this study proposes multi-dimensional filler composite electrode materials with a methyl vinyl silicone rubber matrix. Three types of conductive fillers—namely, zero-dimensional super-conductive carbon black, one-dimensional single-walled carbon nanotubes, and two-dimensional flaky micron-sized silver powder—were employed to construct a hierarchical multi-dimensional conductive network within the silicone rubber matrix via a three-stage fabrication strategy. The electrical conductivity and conductive stability of the as-prepared composite electrode materials were systematically investigated, where the intrinsic mechanisms and evolutionary laws of material electrical performance variations were analyzed. Furthermore, the effects of fillers with different dimensional morphologies on the comprehensive properties of the composites at each fabrication stage were explored, and the optimal filler dosage for each component was determined. Microstructural observations of the staged conductive network formation further verified the rationality of the stage-based functional design model. The optimized composite electrode delivers an initial electrical conductivity of 1.5 × 10⁴ S/m, with only a 14.9% conductivity attenuation under 50% tensile strain, demonstrating excellent electromechanical stability. Moreover, a prototype micro-crawling robot was fabricated using the optimized composite electrode, achieving a maximum linear crawling speed of 8 mm/s. These experimental results validate the feasibility and superiority of the proposed multi-dimensional filler composite strategy. This work provides a novel technical approach for the design and development of high-performance flexible electrode materials for flexible electronic and micro-robotic actuation applications. Full article

Reliable insulation design for LNG feedthroughs requires fundamental dielectric breakdown data obtained under cryogenic LNG conditions. However, such data remain scarce owing to the explosion-proof requirements imposed by the flammable nature of LNG. Furthermore, the influence of phase differences between LNG and NG on creepage dielectric breakdown behavior along insulation surfaces has received little attention. In this study, an explosion-proof cryostat and test facility compliant with the IEC 60079 series of standards were developed, and dielectric breakdown tests were conducted over a range of electrode gap distances and pressures. Two electrode configurations were employed: rod–plate electrodes for dielectric breakdown characterization in LN₂ and LNG, and creepage electrodes for surface dielectric breakdown evaluation in NG and LNG. Experimental results show that LNG requires approximately 1–2 bar of additional operating pressure above that of LN₂ to achieve equivalent dielectric strength. Moreover, LNG exhibited higher creepage dielectric breakdown voltages than NG under all test conditions, with the difference becoming more pronounced as pressure and creepage distance increased. Post-breakdown surface analysis revealed distinct differences in carbonization patterns between the two media. The findings of this study are expected to serve as fundamental reference data for the insulation design of LNG-based cryogenic feedthroughs. Full article

Molecularly imprinted polymers (MIPs) offer robust, cost-effective, and highly selective alternatives to fragile biological receptors. Specifically, electropolymerization has emerged as a versatile strategy that enables the precise, in situ formation of uniform MIP films directly on electrode surfaces. This review provides a comprehensive overview of electropolymerized MIPs (eMIPs) supported on advanced carbon-based materials for electrochemical (bio)sensing. We emphasize how the synergistic integration of eMIPs with carbonaceous architectures significantly enhances electron transfer, active surface area, and overall analytical sensitivity. Key fabrication aspects are systematically discussed, including monomer selection, electropolymerization parameters, and efficient template removal. A central aspect of this work is the critical categorization of sensing mechanisms into direct and indirect detection strategies. This distinction elucidates how eMIPs can quantify a broad spectrum of electroactive and non-electroactive targets in complex matrices, while strategically avoiding excessively high applied potentials. Finally, alongside outlining the transition of these systems into portable technologies, we address a critical shortcoming in the current literature: the urgent need for analytical standardization through the rigorous reporting of Imprinting and Selectivity Factors using Non-Imprinted Polymer (NIP) controls. Full article

Aqueous zinc–manganese dioxide (Zn–MnO₂) batteries are undergoing a paradigm shift from traditional ion-insertion mechanisms to a reversible deposition/dissolution process. By leveraging a two-electron transfer (Mn²⁺/MnO₂), this electrolytic system achieves a high theoretical capacity of 616 mAh g⁻¹ and a theoretical operating voltage of 1.99 V. However, the accumulation of dead Mn, electrically isolated inactive phases, and dynamic interfacial pH fluctuations remain critical barriers to cycle life and practical energy density. This review systematizes a trinitarian strategy to overcome these bottlenecks, focusing on interfacial engineering, redox mediator-assisted recovery, and advanced electrode architectures. We evaluate how anion engineering and pH-buffering stabilize reaction pathways, and how diverse mediators (e.g., halogens, metal ions, and organic molecules) chemically rescue inactive manganese. Furthermore, we examine the integration of 3D carbon networks and low-cost hybrid electrodes to sustain high-areal-capacity deposition. To elucidate these complex mechanisms, we highlight multiscale analytical approaches combining synchrotron X-ray techniques and density functional theory (DFT). Finally, we outline a roadmap for applications ranging from grid-scale flow batteries to flexible wearable electronics. This work provides a comprehensive perspective on realizing sustainable, safe, and high-performance zinc-based energy storage. Full article

Carbon aerogels possess continuous three-dimensional conductive networks, hierarchical pore architectures, and tunable surface chemistry. These structural characteristics make them suitable electrode materials for alkali-metal-ion batteries. This review examines the controlled synthesis and heteroatom doping of carbon aerogels. The discussion links framework construction, electronic-structure modulation, and storage mechanism matching with their electrochemical behavior. The rational design of carbon aerogels should move beyond the simple pursuit of high specific surface area or high dopant content. Effective electrodes require the coordinated regulation of pore architecture, conductive continuity, heteroatom-doped sites, and ion-storage pathways. The current application status of carbon aerogels in alkali-metal-ion batteries is also analyzed from an industrial perspective. A mechanism-oriented and application-oriented framework is therefore required to translate carbon aerogel-based electrodes from structural optimization to a practical battery. Full article

The conversion of bio-waste into functional energy materials provides a robust platform for addressing both environmental and energy challenges. In this paper, discarded absorbent pads are transformed into carbon-rich frameworks, which is followed by the fabrication of composites through the incorporation of Cu₄SnS₄ (CSS) for dual electrochemical applications. Integrating CSS into the waste-derived carbon matrix induces strong synergistic effects, improving electrical conductivity, increasing active-site availability, and accelerating charge-transfer kinetics. Comprehensive physicochemical analyses confirmed the successful formation of a well-integrated heterostructure composite with favorable structural and surface characteristics. Electrochemical evaluations further demonstrated that CSS-modified carbon exhibits superior bifunctional performance. In a two-electrode configuration, the composite delivers an energy density of 12.08 Wh kg⁻¹ at a power density of 250 W kg⁻¹ along with excellent cycling stability in supercapacitor applications. As an electrocatalyst, it achieves a low overpotential of 268 mV at −10 mA cm⁻² and a small Tafel slope of 75 mV dec⁻¹, reflecting efficient reaction kinetics. The strong durability observed in both systems underscores the structural integrity and long-term operational stability of the material. Overall, this paper advances a sustainable waste-to-resource strategy for fabricating multifunctional carbon-based composites, offering a promising platform for integrated energy-storage and hydrogen-generation technologies. Full article