Electrode System Research Articles

Synthesis of biochar and its metal oxide composites and application on next sustainable electrodes for energy storage devices

Biochar materials have been applied in energy storage due to their unique properties, such as high storage of ions, high conductivity, chemical stability and ease of production. Combining it with the high specific capacitance could be a promising strategy to develop devices and improve the properties. Through a hydrothermal technique the biochar powders were synthesized from sugarcane biomass. An acid pretreatment was carried out before and after the graphitization process aiming to obtain carbon materials with high surface area and porosity. The morphological characterization reveals powders with pores of submicrometer diameter. For the pure biochar it was determined a superficial area of 477.66 m2.g−1 with a median pore size of 42.92 Å and a pore volume of 0.21 cm3.g−1. A carbon-based paste was then prepared to deposit on nickel foam and obtain the electrodes. In a 3-electrode system characterization, biochar has showed higher specific capacitance than the metal oxide composites due to higher surface area and higher medium pore diameter. It was calculated a resistance of 2.7 Ω, a capacitance of 446 mF.g−1, a power density of 46.2 W.kg−1 and an energy density of 1.8 W.h.kg−1. These results indicate the potential use of biochar-based electrodes with high electrical conductivity and improved surface area to obtain higher capacitance properties for development of advanced devices.

Recording Cortical and Subcortical Neuronal Activity Using Electrode Systems

Recording Cortical and Subcortical Neuronal Activity Using Electrode Systems

Recording Cortical and Subcortical Neuronal Activity Using Electrode Systems

Recording Cortical and Subcortical Neuronal Activity Using Electrode Systems

Direct solid–vapor approach to 2D FeCoNiP@N-graphene-CNTs as robust electrode material for high-performance supercapacitors

Carbon supported bi(tri)-metallic phosphides are well known high-active electrode nanomaterials as it poses multiple redox sites, excellent electrochemical reversibility, and stability. In spite of that the synthesis of metal phosphides are limited as it involves multiple steps, harsh preparation conditions and often pose poor metal-support interactions. Herein, a simple and direct one-step solvent-free solid–vapor method was developed for the fabrication of bi(tri)-metallic phosphides supported N-graphene/N-CNTs 2D-nanosandwidch, first report to the best of our knowledge. Unique surface morphology, high surface area, good thermal stability and strong metal-support interaction, were confirmed for the as prepared electrocatalysts (FeNiP/NCNTs, FeCoP/NCNTs and FeNiCoP/NCNTs). In three electrode system, the FeNiCoP/NCNTs showed highest specific capacitance of 1479F/g at 1 A/g in 3 M KOH and excellent cycling stability, with capacitance retention of 90.8 % over 5000 cycles. Interestingly in the two-electrode system, the FeNiCoP/NCNTs demonstrated impressive capacitance of 245F/g at 1 A/g, power density of 10567 W/kg and energy density of 66.7 Wh/kg, with excellent retention of 91.5 % over 5000 cycles. The direct one-step preparation and high electrochemical performance inclusively promote the present FeNiCoP/NCNTs (with low metal loading of less than 10 wt%) as a promising supercapacitor electrode nanomaterial for energy storage applications.

Fabrication and Electrochemical Insights into Advanced rGO-modified Ternary Cu-doped NiFe2O4/TiO₂ Electrodes for High Performance Supercapacitors

In this study, we employed a comparative approach by evaluating the composites CuFe2O4-rGO-TiO2 (CFRT4), NiFe2O4-rGO-TiO2 (NFRT5) and Cu0.5Ni0.5Fe2O4-rGO-TiO2 (CNFRT6) against single compounds, CuFe2O4 (CF1), NiFe2O4 (NF2) and Cu0.5Ni0.5Fe2O4 (CNF3). The electrodes were fabricated using drop-cast technique and investigated using XRD, FESEM, FTIR, XPS, VSM and BET. CNFRT6 showed highest specific surface area of 14.57 m2/g. Using symmetric two electrode system with 3M H2SO4 electrolyte, in CV analysis, specific capacitance of CNFRT6 was determined to be 48.4 F/g at 10 mV/s. GCD analysis revealed that CNFRT6 attained highest specific capacitance value of 213.18 F/g at the current density of 0.25 A/g. The CNFRT6 yielded energy density (Ed) of 18.95 Wh/Kg at current density 0.25 A/g. Further, it achieved power density (Pd) of 1200 W/Kg at 3 A/g. Obtained results suggest that Cu0.5Ni0.5Fe2O4-rGO-TiO2 composite exhibited enhanced electrochemical properties and thus, it can be employed to fabricate electrodes for application in supercapacitors.

Electrocatalysis degradation of biochemical tail water from coking wastewater using particle electrode with persulphate

ABSTRACT Due to the intricate composition and recalcitrant nature of coking wastewater, the biochemical effluent often fails to meet standards. This study explored the preparation of particle electrodes, utilizing activated carbon powder (PAC) loading single-element Fe, Co, and Ni, as well as dual-element Ni–Fe and Co–Fe as catalyst. The particle electrode system was integrated with persulphate (PS) activation to enhance its performance. The effects of potassium persulphate (KPS) dosages, currents, and Ni:Fe ratios were investigated. The results showed that bimetallic particle electrodes outperformed their monometallic particle electrodes. Among the five electrode materials, Ni–Fe/PAC achieved the best degradation efficiency of 84.4% and the lowest energy consumption of 19.73 kW·h·kg−1 COD. When the initial concentrations of TOC and COD were set at 300 and 280 mg L−1, the Ni–Fe/PAC with 5 mmol L−1 KPS achieved removal efficiencies of 61.7 and 84.4%, respectively. The metals on Ni/PAC and Co/PAC existed in the zero-valent state, while Fe on Fe/PAC was present as Fe2O3. Co–Fe/PAC exhibited the formation of CoFe2O4 oxides. Ni–Fe/PAC possessed the lowest hydrogen evolution reaction potential (−0.28 V), and the highest oxygen evolution potential (2.4 V), and reached an electrochemical active surface area (ECSA) of 236.3 cm2. Cyclic voltammetry (CV) curves indicated that the direct redox reactions and indirect oxidation of pollutants occurred concurrently. Both •OH and ⋅ SO 4 − radicals played crucial roles during the degradation processes. The degradation efficiency of organic matter was as follows: benzene compounds (88.4%) >heterocyclic compounds (75.3%) >polycyclic aromatic hydrocarbons (53.9%).

Electric field-controlled on-demand surface deformation in liquid crystal polymer networks with topological defects

ABSTRACT Reconfigurable surface morphing control of liquid crystalline polymer (LCP) films at micro or nano scales has emerged as a promising strategy for various applications. Creating reproducible and adjustable platforms enhances their versatility. This study presents a method for controlling stimuli-responsive deformations in liquid crystal polymer network (LCN) films by forming defect arrays using a three-dimensional (3D) electric field generated by crossed electrode systems. The director field of the system can be simulated, enabling investigation of high-temperature deformations through activation force density calculations. To explain the laterally asymmetric deformation of our film, a 3D analysis of the activation force density vector field was essential. Topographical modifications at room temperature are also achieved by incorporating dichroic dye to the monomeric mixture, which promote local monomer diffusion during photopolymerisation. Additionally, by varying the configurations of signal and ground electrodes, different defect structures are generated, leading to distinct deformation patterns at elevated temperatures. Our findings demonstrate that LCN films in this study exhibit programmable nanometre-scale shape deformations, allowing for varied surface patterns from a single setup. This platform significantly enhances the potential of nano- or micro-morphing LCP coatings for advanced applications across multiple fields.

Sulfurization of ternary NiCoZn layered double hydroxides for enhanced and durable alkaline overall water splitting

Designing an efficient bifunctional cost-effective electrocatalyst for overall water splitting is strongly coveted for the commercialization of green hydrogen production. In this work, novel sulfurization of ternary binder-free NiCoZn LDH on nickel foam was carried out with different amounts of thiol source via a simple hydrothermal method. All the samples were characterized for their phase, structure, functional groups, morphology, surface elemental analysis, and surface area. The sulfurized samples possess a sheet-like morphology with a high surface area of about 547.8 m2 g-1. The optimally sulfurized (NCZ-S) electrode exhibited a lower overpotential of 272 mV and 352 mV to achieve a current density of 100 mA cm-2 with small Tafel values of 87.2 mV dec‑1 and 103.3 mV dec‑1 for HER and OER respectively. The overall water splitting was carried out with the NCZ-S electrode, which required a small electrolytic cell potential of 1.62 V. The electrode system was stable for an enduring time of 150 h with no activity loss. The efficient and feasible sulfurization step dramatically improves the overall activity and stability of the pristine electrodes which is also verified by the DFT studies.

Investigation of the Electrochemical Methylene Orange Effluent Degradation Using Graphite Battery Waste and Seawater

Electrochemical degradation using seawater and graphite electrodes from waste batteries for methylene orange (MO) dye degradation has been successfully carried out. Electrode characterization, electrolyte calibration, and dye degradation effectiveness with various voltages, pH, kinetics, and degradation reaction mechanisms were observed. Characterization showed a characteristic 2θ peak by X-ray diffractometer (XRD) at 26.5 °, and scanning electron microscopy-energy dispersive X-ray spectrometer (SEM-EDX) showed the morphology of hollow grains with carbon (C) and oxygen (O) composition. In addition, scanning potentiometry showed the initiation of hypochlorite compound formation and MO degradation. Further study of degradation effectiveness showed optimal results at 3 volts and above voltages. Hypochlorous acid (HOCl) and hypochlorite ions (OCl-) from seawater are very effective oxidizing agents in acidic conditions compared to other pH conditions. Pseudo-first-order kinetics regulate the electron attack from the hypochlorite oxidizer (OCl-), the hydroxyl groups (•OH) from the seawater electrolysis mechanism with graphite electrode media on the reactive groups, the ring binding on MO, and the degradation. This indicates that the graphite electrode system used to reuse waste batteries and seawater has the potential to degrade waste dyes in aquatic environments. HIGHLIGHTS Electrochemical system with graphite electrode battery waste and seawater electrolyte. Characterization with XRD, SEM-EDX, spectrometry, and potentiometry. Analysis of the effect of voltage and pH treatment variation. Kinetic and degradation mechanism of methylene orange. GRAPHICAL ABSTRACT

Screen-printed textile substrates’ suitability as a platform for electrochemical sensors’ construction

Electronic sensors are essential in applications like biosensors and fuel cells, providing rapid solutions for substance detection. Integrating electrochemical sensors into textiles offers advantages such as flexibility, comfort, and potential for wearable applications. This study explores the suitability of three textile substrates—100 % polyester knit mesh (S1), 100 % recycled polyester knit mesh (S2), and 50 % recycled polyester/50 % hemp fabric (S3)—for constructing screen-printed electrodes (SPEs). The goal is to develop a textile-based electrochemical sensor with a 3-electrode system (reference, auxiliary, and working electrode) using semi-automated screen printing. The electrochemical performance of two carbon inks, Elantas 9553 and DuPont BQ242, was evaluated to select the best working electrode (WE) ink. DuPont BQ242 was found most suitable for WE production, exhibiting quasi-reversible behavior and temperature stability. The electrochemical behavior of the textile-SPEs printed with DuPont BQ242 revealed that substrate S3 had superior properties, with higher peak currents (peak current ratio of 1.2) and smaller peak potential separation (602 n/V). Carbon Elantas 9553 was more sensitive to temperature changes (1 % variation) than the more stable DuPont BQ242 (0.03 % variation). The stability of the inks on substrates was examined using the 4-point probe method, highlighting excellent electrical stability under UV, high temperatures, cosmetics, and artificial sweat. The final textile-based SPE outperformed commercial SPEs, showing superior redox properties, with a peak potential separation (ΔEp) 56 % smaller and a relative standard deviation (RSD) of 1.58 % over 20 measurements. These textile-based SPEs present a valuable alternative to conventional rigid sensors, which are typically single-use and less durable.

Application and prospects of interface engineering in energy storage and conversion of graphdiyne‐based materials

AbstractA new carbon allotrope, graphdiyne (GDY) has great promise for future use. Much interest was piqued when it was initially prepared in 2010. GDY is made up of sp‐ and sp2‐hybridized carbon atoms. It has a one‐atom thick two‐dimensional structure and many interesting and useful qualities, such as strong chemical bonds, super‐large π structures, the ability to change from an alkyne to an alkene, and can be grown on any surface. GDY has become one of the frontier hotspots in chemistry and materials science, with original research achievements in energy conversion and storage, catalysis, intelligent information, life sciences constantly emerging and so on, showing revolutionary performance. In electrochemical cells, the electrode interface content not only accounts for a small proportion in the entire electrode system but it also plays a crucial role, affecting the efficiency, lifespan, power performance, and safety performance of the battery. In view of this, the intrinsic properties of GDY have been thoroughly analyzed, and a new GDY‐based electrochemical interface has been proposed by combining the key problems of electrochemical interfaces in electrochemical energy storage and conversion. This has led to new understanding and insights to address many critical scientific issues. In this review, the structure, characteristics, and applications of GDY in interface engineering are presented. In particular, recent advances in GDY and its aggregates in energy storage and conversion are summarized and discussed.

Assessment of Oil Paints for Corrosion Protection of Reinforcing Steel Bars in Concrete

Corrosion becomes a threat to reinforced concrete structural integrity during the service life of the structural member. This situation has become a global concern because of the economic and safety implications. Hence, many corrosion inhibition techniques including coating with materials (organic and inorganic) were used to prevent its devastating effects. The present study used three oil paint brands (mat, red-oxide and gloss Leyland oil paints in Ghana) to variedly coat reinforcing steel bars to ascertain their corrosion protection capacity in concrete. There were zero, one, two and three paint coats of average film thickness, 72 µm, 129 µm and 220 µm respectively explored. An Electrochemical process involved simulated concrete pore solution made of 10% sodium chloride (NaCl) in distilled water with three electrode systems to represent a corrosion medium was used to determine corrosion protection capacity of the paints. The results indicate over 90% corrosion resistance of the paints used. Comparing the corrosion rates of the coated and uncoated reinforcing steel bars, while it would take a one coat steel bar 342.5 years and 237 years respectively for spraying and manual brushing modes to reduce in diameter by 0.616mm, it would take only one year for an uncoated steel bar to reduce by this same 0.616mm. The protection capacity proved better with increasing coats on all corrosion variables for the selected paints used. The implication is that the selected oil paint brands are capable of protecting reinforcing steel bars in concrete against corrosion and therefore recommended for application to reduce maintenance cost. Statistically, no significant difference existed between coating mode, number of coatings, paint type and steel type on the corrosion variables for the coated steel bars. However, a further study about the durability of the coating in the concrete during its service time is recommended.

ZIF-67 derived N doped carbon embedded CoxP for superior hydrogen evolution

Abstract Developing a sustainable non-noble hybrid electrocatalyst for effective electrocatalysis is the most crucial task; particularly in sustainable hydrogen energy production in the realm of energy conversion. In this work, effective thermal pyrolysis process followed by phosphorization strategy was employed to prepare and fabricate ZIF-67 (Zeolitic imidazole) assisted Co2P/N doped carbon electrocatalyst for hydrogen evolution reaction (HER). The optimized Co2P/N–C electrocatalyst exhibited hollow porous nanostructures as confirmed from the scanning electron microscopy. The achieved porous nanostructure improved the efficiency of the charge and mass transportation which is confirmed by the BET analysis, has high surface area value of 94.731 m2/g. In addition, a transition metal atom can regulate reactants adsorption and desorption capacity by modulating Co and P electronic configuration. The electrochemical studies of fabricated ZIF-67 derived Co2P/N–C electrode were analyzed using 1.0 M alkaline potassium hydroxide (KOH) medium in 3 electrode system process. Whilst, optimizing the pyrolysis temperature during the phosphorization will remarkably enhance the favourable characteristics of the hydrogen generation. Notably, the optimized ZIF-67 derived Co2P/NC at 350 °C electrode exhibited low overpotential (135 mV) at minimum 10 mA/cm2 and low 120.3 mV/dec Tafel slope. Besides, electrode stability at 10 mA/cm2 current density was verified by chronoamperometry test. Hence, this study furnishes the potential technique for the development of advanced hybrid MOF electrocatalyst as a successful alternative on large scale.

A solar thermoelectric system by temperature difference for efficient removal of chromium (VI) in water and soil

In this work, we designed and developed a facile solar thermoelectric generator (STEG)-based system and a new electrokinetic remediation (EKR) system, which consists of main electrodes and unenergized auxiliary electrodes. The prepared nanocomposite was investigated for the effectiveness of the STEG+PANI-CNT/GF system in remediating Cr-contaminated. Photothermal performance test were applied in order to examine this STEG could export a power density of 365.56 mW/dm2 and output potential of 801 mV at the temperature difference of 50 ℃. Thus the STEG could be used as the power to construct a Cr(VI) removal system using polyaniline (PANI) film/carbon nanotubes (CNT) modified graphite felt (GF) electrode (PANI-CNT/GF) as cathode and graphite rod as anode. The as-prepared STEG+PANI-CNT/GF system exhibited a significant Cr(VI) removal efficiency (96.2 % in water) through electromigration, electro-adsorption and electroreduction. Moreover, a multi auxiliary electrodes (AEs) system (STEG+PANI-CNT/GF+AEs) with six PANI-CNT/GF auxiliary electrodes was constructed in remediating Cr(VI)-contaminated soil, showing Cr(VI) removal efficiency of 16.7–60.1 % higher than that of STEG+PANI-CNT/GF. The PANI-CNT/GF auxiliary electrodes could bind Cr(VI) and adjust electric field distribution, contributing to adsorption and reduction of Cr(VI). Consequently, this work provides a promoting approach for heavy metals removal in future application.

Model‐Based Exploration of Web Guiding Behavior for a Novel Battery Cell Stacking Process

Innovative production processes are required to meet the rapidly growing demand for batteries and the associated material trends. In particular, the process step of stack assembly using new machine concepts promises a high potential for optimization. However, these concepts are untested in practice. The use of digital models makes it possible to develop corresponding optimization approaches. This article presents the development of a model for the web guiding systems of electrodes and its integration into an overall machine model for a novel machine concept. Finally, optimization approaches are identified by determining appropriate controller parameters for the web guiding systems.

Highly specific detection of ROR1 cancer biomarker with bipolar electrochemiluminescence.

An electrochemiluminescence (ECL) detection system is presented integrated with a bipolar electrode system for sensitive cancer diagnosis. In order to achieve the highest electrical conductivity and redox-active surface area, MXene was chosen as the material for the bipolar electrode. As part of the detection process, the anodic pole of the bipolar electrode was modified with the receptor tyrosine kinase like orphan receptor 1 (ROR1) antibody, followed by an immunoassay using the ROR1 antibody-modified Ag triangle that was identified as significantly enhancing ECL. We measured the ECL of luminol using the anode pole of BPE as an analytical signal in the presence of H2O2. Additionally, 3D-printed microchannels were used to fabricate the BPE system, to reduce the quantity of sample required. It has been shown that the present immunosensors are low-cost and sensitive in detecting types of cancer, with an extended linear range of 10 fg mL-1 to 1 µg mL-1 in the analysis of synthetic samples and achieving an accuracy of ~ 90% in diagnosing ten unknown real samples.

Electroanalysis of Statin Drugs: A Review on the Electrochemical Sensor Architectures Ranging from Classical to Modern Systems.

An overview of the latest advances in the design of electrochemical sensor architectures dedicated to the determination of drugs from the statin class is presented in this review. Statins are drugs widely consumed for cholesterol control, and their determination in different matrices through the application of electroanalysis is growing considering advantages such as operational simplicity, lower cost and ease of sample preparation. Within the context of statins, electrochemical sensor architectures can be subdivided into conventional/classical electrodes such as glassy carbon electrodes, carbon paste electrodes, pencil graphite electrodes, boron-doped diamond electrodes and metallic electrodes, and more modern electrode systems, including the screen-printed electrodes and 3D-printed electrodes. Thus, different aspects related to the preparation of these electrochemical sensors and analytical performance are presented, also reflecting advances in terms of designs of new architectures and possible improvements not previously reviewed. Analyzed samples, advantages and disadvantages of different implemented sensor's modification strategies and perspectives for the electroanalysis of statins are also included throughout the work.

Enhanced 3D-printed Matrix for Electrocatalytic Detection: A Practical and Simple Electrochemical Platform

AbstractIn this work, we proposed a novel 3D-printed manufactured electrode system. A project was developed and optimized, compatible with commercially available potetiostats. Additive manufacturing included the modification of the pseudo-reference electrode by electrodeposition of silver and its subsequent oxidation to the Ag/AgCl form. Then the system was tested using electrochemical techniques to check the application as a universal electroactive platform. As an example, we checked the detection of paracetamol as a common substance from non-steroidal anti-inflammatory drugs (NSAIDs). Finally, the system was compared to available commercial carbon electrodes, considering the screen-printed electrode (SPE no.1 and SPE no.2) and the glassy carbon electrode (GCE), showing higher sensitivity and linearity range compared to commercial screen-printed systems. The novelty of the proposed platform unveils a new way of common, simple, budget, and fast obtaining a universal electroactive platform for electrochemical research, keeping high-performance parameters.

Novel Ball-Type Phthalocyanines with Eight Benzotriazole Groups: Synthesis, Computational DFT Studies, and Supercapacitor Properties

Novel four MBTOB-bridged ball-type metallophthalocyanines were obtained from 4,4′-((methylenebis(6-(2H-benzo[d][1, 2, 3]triazol-2-yl)−4-(2,4,4-trimethylpentan-2-yl)−2, 1-phenylene))bis(oxy))diphthalonitrile by means of transition metal (II) acetate salts in 2-dimethylaminoethanol. The new starting bisphthalonitrile compound was accomplished from 2,2′-methylenebis[6-(benzotriazol-2-yl)−4-tert-octylphenol] and 4-nitrophthalonitrile in dimethylformamide under the catalysis of potassium carbonate at 50 °C. The structural characterization of the compounds was accomplished by infrared, proton-nuclear magnetic resonance, matrix-assisted laser desorption/ionisation time-of-flight mass, and ultraviolet–visible spectroscopic methods. The supercapacitor performances of the electrodes were examined by cyclic voltammetry, galvanostatic charge discharge, and electrochemical impedance spectroscopy analyses. The specific capacitances obtained from the GCD measurements were calculated as 320.4 ± 15.1 F g−1 for ball-type zinc (II) phthalocyanine in three electrode systems. The highest specific capacitance value was found in the electrode containing ball-type nickel (II) phthalocyanine as 929.8 ± 32.8 F g−1 at a scan rate of 100 mV s−1. In symmetric supercapacitor measurements, the capacitance retention value was 100.7% after 5000 cycles.

Preparation of Tectona grandis Leaves derived Activated Carbon for High-Performance Supercapacitor Application

In energy-based applications, biomass porous micro/nanostructures activated carbon materials are the significant candidates, because of their high specific surface area, superior electrical conductivity, affordability and environmental friendliness. In this work, the activated carbon was prepared from Tectona grandis leaves as a biomass, and thus activated by 25% K2CO3 solution. The prepared carbon was designated as TGLAC. Second carbon was prepared from TGLAC was doped with urea and named as N-doped TGLAC. The physico-chemical analytical methods were employed to access the phase structure, bonding nature and morphological properties of the freshly prepared activated carbon material. Three electrode systems were utilized to estimate the supercapacitor features in 1 M Na2SO4 electrolyte. The prepared activated carbon electrode provides a specific capacitance of 371 F g–1 at 1 A g–1 and a 62% rate capability at 5 A g–1. It retains 94% of its initial capacitance during the cyclic stability analysis at 5 A g–1 over 5,000 cycles. This study demonstrates that carbon based materials obtained from sustainable waste biomass can exhibit favourable electrochemical performance in energy applications, providing a clear and feasible synthetic approach and strategy for their utilization.