Graphite Electrode Research Articles (Page 1)

In this study, we investigate the electrochemical performance of a carboxyl-functionalized pencil graphite (CFPG) electrode for chloride ion oxidation and its subsequent application in dye degradation. The graphite electrode was chemically modified using acetic acid to introduce –COOH functional groups, enhancing surface polarity and chloride adsorption capacity. Surface characterization by SEM, EDX, and XPS confirmed morphological changes and oxygen enrichment following functionalization. Electrochemical measurements demonstrated a positive shift in open circuit potential (OCP) and significantly enhanced chloride oxidation activity, as evidenced by cyclic voltammetry (CV) in 0.1 M KCl. The functionalized electrode facilitated the in situ generation of reactive chlorine species (RCS), with spectral features near ~240 nm consistent with HOCl/ClO− and a broader band around ~450 nm attributable to chlorine-derived intermediates rather than exclusively to molecular chlorine. These species played a central role in degrading structurally diverse dyes—Kenacid Green and Brilliant Green—via oxidative pathways. The results highlight the potential of low-cost, –COOH-modified graphite electrodes as effective platforms for the RCS-mediated electrochemical treatment of organic contaminants.

Abstract Graphite, a widely used anode material in lithium-ion batteries, possesses a layered microstructure that induces anisotropic diffusion properties and non-spherical particle morphologies. These features challenge conventional modeling approaches, which often assume spherical symmetry and homogeneous structure. In this study, we develop a three-dimensional heterogeneous electrochemical model that explicitly reconstructs graphite particles as ellipsoids, incorporating axis-dependent diffusion coefficients to capture anisotropic ion transport. We identify critical mesoscale design principles that govern rate performance by varying tortuosity, porosity profiles, and particle orientation. Our results reveal that (i) ionic transport resistance is highly sensitive to ellipsoid orientation, affecting overall polarization; (ii) electrodes with more uniform particle distributions exhibit lower tortuosity and higher diffusion-limiting currents; and (iii) aligning the basal planes of graphite along the electrode thickness direction significantly enhances rate capability. These insights offer guidance for optimizing electrode architectures, and suggest that advanced fabrication techniques, such as dry pressing with PTFE binders, may be effective for aligning anisotropic particles to enhance high-rate performance.

Introduction: The recognition of the health hazards of azo dyes has highlighted the need to develop efficient, rapid, and reliable analytical methods for dye determination. Method: In this work, electrochemical probing of the azo group of Tartrazine (TZ) and Carmoisine (CR) in food dyes was carried out. Synthesized bismuth and zinc oxide nanoparticles were used to modify Graphite Electrode (GE). Results: Electrochemical analysis showed a much better electrochemical response using ZnO+Bi/GE as a modifier than individually nanoparticle-modified graphite electrodes. From the CV analysis, it was found that both the dyes exhibited irreversible electrochemical behavior, and the redox parameters were calculated. The Limit of Detection (LOD) values recorded for TZ and CR for ZnO+Bi/GEbased sensors were 0.84 uM and 2.80 uM, respectively. The obtained sensitivity values were 11.86 uA/uM/cm2 for TZ and 17.3 uA/uM/cm2 for CR. Conclusion: The sensor evidently demonstrated reliable simultaneous detection of both dyes, making it suitable for practical applications in food safety analysis.

A gold nanoparticle-enhanced methylene blue electrochemical sensor for detecting waterborne anionic surfactants and PFAS.

An ultrasensitive electrochemical sensing platform for thiamethoxam detection using novel iron-organic framework anchored graphite rod electrode

Straightforward screening of ketamine in forensic samples using voltammetry with screen-printed carbon graphite electrodes.

Novel electrolytes for advanced lithium-ion batteries (LIBs) with higher energy density and safety are being extensively explored. A major challenge in developing new electrolytes is achieving reversible Li+ intercalation into graphite negative electrodes. In commercial LIBs, this reaction is reversible in ethylene carbonate (EC) electrolytes, whereas unfavorable Li+-solvent cointercalation occurs in many other electrolytes. Recently, EC-free Li+ intercalation has been achieved in some types of advanced electrolytes, including (localized) highly concentrated electrolytes and weakly coordinating electrolytes. However, an essential factor that dominates whether Li+ intercalation or Li+-solvent cointercalation occurs has yet to be identified. Herein, the electrolyte Li+ chemical potential is reported as a quantitative descriptor of the Li+ intercalation behavior. Solvent cointercalation is generally inhibited above a certain threshold of the electrolyte Li+ chemical potential. This work provides a novel guideline for designing advanced LIB electrolytes.

COVID-19, caused by SARS-CoV-2, has created unprecedented global health challenges, necessitating rapid and reliable diagnostic strategies. The spike (S) protein, particularly its S1 subunit, plays a critical role in viral entry, making it a prime biomarker for early detection. In this study, we present a disposable, low-cost, and portable electrochemical biosensor employing specifically optimized aptamers (Optimers) for SARS-CoV-2 S1 recognition. The sensing approach is based on aptamer–protein complex formation in solution, followed by immobilization onto pencil graphite electrodes (PGEs). The key parameters, including aptamer concentration, interaction time, redox probe concentration, and immobilization time, were systematically optimized by performing electrochemical measurement in redox probe solution containing ferri/ferrocyanide using differential pulse voltammetry (DPV) technique.Under optimized conditions, the biosensor achieved an ultralow detection limit of 18.80 ag/mL with a wide linear range (10−1–104 fg/mL) in buffer. Importantly, the sensor exhibited excellent selectivity against hemagglutinin antigen and MERS-CoV-S1 protein, while maintaining high performance in artificial saliva with a detection limit of 14.42 ag/mL. Furthermore, its integration with a smartphone-connected portable potentiostat underscores strong potential for point-of-care use. To our knowledge, this is the first voltammetric biosensor utilizing optimized aptamers (Optimers) specific to SARS-CoV-2 S1 on disposable PGEs, providing a robust and field-deployable platform for early COVID-19 diagnostics.

Choline chloride and ethylene glycol mixtures with 1:2, 1:4, and 1:6 molar ratios on the surfaces of graphite and gold electrodes were studied using classical molecular dynamics simulations. Both neutral and charged electrodes were considered. The liquid composition, solvation structure, molecular orientation, and dynamics at the electrode surface are significantly different from those of the bulk liquid. These properties strongly depend on the electrode material and charge density, whereas they are less sensitive to the overall solvent composition. The effect of the electrode on the composition, structure, and orientation of the liquid fades beyond ∼10Å from the surface of the electrode. This distance corresponds to about two layers of the structured solvent, despite the fact that the layered structure extends to at least five layers or about 25Å. However, the electrode influences solvent dynamics over a longer distance. The electrochemical properties of the eutectic solvent at both electrode surfaces were also studied. The simulations captured the experimental differential capacitance shapes for both electrode systems, although the magnitudes and exact shapes differ. The simulations further revealed that the solvent in the first solvation layer can both overscreen and underscreen the electrode charges depending on the electrode material and electrode potential.

Gold nanoparticles @ nitrogen-doped carbon dots modified pencil graphite electrode as an extremely sensitive sensor for trace analysis of ciprofloxacin

This study examines the performance of an innovative electroecological system for treating brackish sewage in five cycles with different salinity concentrations. Two systems were designed: a control and electroecological system using a halophytic-constructed wetland (Juncus rigidus, retention time 96h) and an electrolytic cell (graphite electrode, external electric potential of 12V applied for 8h). The system effectively removed pollutants such as salinity (48-61.94%), COD (83.56-87.76%), BOD5 (94.90-96.55%), TSS (90-92%), PO43--P (98.46-99.6%), NH4+-N (99.65%), NO3--N (71.94-91.96%), and NO2--N (79.66-86.88%) were achieved along with heavy metals like Cr (99.9%), Mn (47-55.97%), Mo (60.14-99.9%), Cd (30.77-99.9%), Zn (11.21-18.78%), and Al (14.93-99.9%) from wastewater and followed first-order kinetics. The electroecological system's effectiveness was validated using statistical techniques like PCA and the Mann-Whitney U test. Pathogens, including Vibrio, E. coli, Pseudomonas, fecal Coliform, and Aeromonas, were nearly 99.9% removed, along with 99% of organic compounds, including emerging pollutants. Ion chromatography and inductively coupled plasma were used to study the accumulation of ions (Cl-, SO42-, Na+, K+, Mg2+, and Ca2+) in Juncus and their removal in water (around 83.15% K+, 30.53% SO42-, 29.53% Cl-, 26.45% Mg2+, 13.58% Na+, and 9.50% Ca2+). Juncus was efficient in accumulating K+ (66.99%) and Mg2+ (42.32%) ions. The electroecological system's physical and biochemical analysis shows no salinity stress, showing potential for treating brackish sewage. No research has been reported on treating brackish sewage using a Junucs-based CW-electrolytic cell in the literature. It is a novel approach for independent wastewater treatment in coastal, remote, and rural areas.

Abstract Ni‐rich layered oxides are promising positive electrode materials for lithium‐ion batteries (LIBs) owing to their high energy density and cost efficiency. Nevertheless, the intrinsic chemicophysical instability of Ni‐rich layered oxides severely limits the massive application. Herein, a unique gradient structure design from coherent rock‐salt phase surface structure to quasi super‐lattice matrix on the sub‐surface of single‐crystalline LiNi0.83Co0.11Mn0.06O2 (GS‐SC‐NCM) is proposed to improve their stability. The introduced Ti4+/Nb5+/Zr4+ ions are able to alleviate the overlay of O 2p and Ni 3d bands at the highly delithiated state, remarkably improving the stability of anion skeleton. Moreover, intragranular cracks and undesired lattice shrinkage during the H2‐H3 phase transition are greatly suppressed due to the ultra‐stable gradient structure design. In addition, the inert rock‐salt‐like phase on the surface of GS‐SC‐NCM hinders continuous evolution of interphase. Consequently, the superior cycling stability of GS‐SC‐NCM with high capacity retention of 92.9% after 150 cycles is achieved. Moreover, an Ah‐level pouch cell consisting of GS‐SC‐NCM positive electrode and commercial graphite negative electrode exhibits extraordinary cycling stability at 1C with 89.8% capacity retention after 450 cycles. This work represents significant progress in stabilizing single‐crystalline Ni‐rich layered oxides for an advanced secondary battery system, which is pivotal for accelerating the current electrification process.

Lithium-ion batteries (LIBs) are a promising alternative to lead–acid batteries, offering environmental benefits and cost effectiveness. Their performance depends on the development of anode materials with high theoretical capacities and rapid ion diffusion. In this study, we investigated the potential of copper silicide (Cu3Si) as an anode material for LIBs using first-principles calculations. The energy versus volume plot and phonon dispersion analysis confirm its structural stability, further supported by a negative formation energy of –1901.8[Formula: see text]eV. Electronic structure analysis revealed that Cu3Si is a semiconductor with an indirect bandgap of 1.71[Formula: see text]eV. Elastic property calculations, including the bulk modulus, Young’s modulus, shear modulus, Zener anisotropy factor, [Formula: see text] ratio and Poisson’s ratio, indicate strong mechanical stability with a soft and flexible nature compared to conventional electrode materials. Electrochemically, Cu3Si exhibits excellent cyclic and electrochemical stability, maintaining a relatively stable voltage profile with minimal polarization, good reversibility, and low overpotential. Among the calculated electrode materials, the Cu3Si composite exhibited superior cycling stability, maintaining over 70% of its initial capacity after 500 cycles. This enhanced performance is attributed to its ability to effectively buffer volumetric changes during lithiation, outperforming both silicon and commercial graphite electrodes. Similarly, voltage–capacity analysis revealed that Cu3Si offers a stable voltage profile with minimal polarization, outperforming silicon and graphite in terms of electrochemical reversibility and cycling stability. These characteristics underscore its potential as a high-performance anode material for next-generation LIBs.

Developing bifunctional electrocatalysts that simultaneously enable green hydrogen production and water purification is essential for advancing sustainable energy and environmental technologies. In this study, we present Cu@Pd core–shell nanostructures fabricated through template-assisted electrodeposition of Cu, followed by galvanic Pd modification on pyrolytic graphite electrodes (PGEs). The optimised catalyst exhibited superior hydrogen evolution reaction (HER) activity, with an onset potential of 70 mV, a low Tafel slope of 33 mV dec−1 and excellent stability during prolonged HER operation. In addition to hydrogen evolution, Cu@Pd/PGE shows significantly enhanced nitrate reduction reaction (NRR) activity compared to Cu/PGE in both alkaline and neutral conditions. Under ideal conditions, the catalyst achieved 60% nitrate removal with high selectivity towards ammonia and minimal nitrite formation, emphasising its superior performance. This enhanced bifunctionality arises from the synergistic Cu–Pd interface, facilitating efficient nitrate adsorption and selective hydrogenation. Despite their high catalytic activity for both HER and NRR, the Cu@Pd nanostructures could often emerge as a versatile platform for integration into sustainable hydrogen production and an effective denitrification process.

In this study, bromocresolpurple was electropolymerized on thesurface of a pencil graphite electrode (PGE) and electrochemicallydoped with cerium (Ce) nanoparticles. The Ce-doped poly­(bromocresolpurple) (Ce/PBCP)-modified PGE was characterized using energy dispersiveX-ray spectroscopy, scanning electron microscopy, and X-ray photoelectronspectroscopy. The prepared Ce/PBCP electrode was investigated forthe electrochemical determination of melatonin in the presence ofdopamine. The electrochemical activity of the Ce/PBCP electrode wascompared with that of undoped PBCP, Ce/PGE, and bare PGE. The peakpotential and peak current for melatonin oxidation were +800 mV and820 μA cm–2, respectively. The detection limitof melatonin was 0.038 μM, and the Ce/PBCP electrode exhibitedhigh activity in the presence of interfering species. In addition,the use of a Ce/PBCP electrode for detecting melatonin in a terebinthsample, a real food sample, was also investigated, and the producedelectrode demonstrated high performance.

The paper presents experimental results for a modified pulsed plasma thruster (PPT) with solid propellant, using a coaxial anode–cathode design. Graphite from pencil leads served as propellant, and a tungsten trigger electrode was tested to reduce carbonization effects. Experiments were performed in a vacuum chamber at 0.001 Pa, employing diagnostics such as discharge current/voltage recording, power measurement, ballistic pendulum, time-of-flight (TOF) method, and a Faraday cup. Current and voltage waveforms matched an oscillatory RLC circuit with variable plasma channel resistance. Key discharge parameters were measured, including current pulse duration/amplitude and plasma channel formation/decay dynamics. Impulse bit values, obtained with a ballistic pendulum, reached up to 8.5 μN·s. Increasing trigger capacitor capacitance reduced thrust due to unstable “pre-plasma” formation and partial pre-discharge energy loss. Using TOF and Faraday cup diagnostics, plasma front velocity, ion current amplitude, current density, and ion concentration were determined. Tungsten electrodes produced lower charged particle concentrations than graphite but offered better adhesion resistance, minimal carbonization, and stable long-term performance. The findings support optimizing trigger electrode materials and PPT operating modes to extend lifetime and stabilize thrust output.

Abstract This study employs Grey Relational Analysis (GRA) to optimize the Electric Discharge Machining (EDM) process parameters for AISI P20 tool steel, focusing on the influence of different electrode materials copper, brass, and graphite on key performance metrics such as material removal rate (MRR), tool wear rate (TWR), and surface roughness (SR). The objective was to identify optimal parameter settings that simultaneously enhance machining efficiency, extend tool life, and improve surface quality for P20 tool steel, which is widely used in injection molding applications. Experiments were designed using a Taguchi L9 orthogonal array by varying discharge current, pulse-on time, pulse-off time, and gap voltage. The results indicate that copper electrodes delivered high productivity with controlled tool wear and acceptable surface finish. Brass electrodes achieved superior surface quality, while graphite electrodes showed minimal tool wear but compromised surface integrity. The novelty of this work lies in the application of GRA for simultaneous multi-response optimization, offering a robust framework for selecting electrode-specific parameters to balance productivity and quality in EDM of P20 tool steel.

Organic electroactive materials (OEMs) are featured with superior structural designability and ready accessibility from biomass or industrial plastics recycling, and they have emerged as important building blocks for future battery technology. Coupling OEMs with nonvolatile solid electrolytes offers the possibility for improving the technological sustainability and inherent safety of rechargeable batteries. This report delves into the representative carbonyl-based OEM, lithium terephthalate (Li2C8H4O4, LTPA), and prevailing graphite anode, and systematically investigates their fundamental properties with polyether-based electrolytes utilizing two sulfonimide anions (i.e., bis(fluorosulfonyl)imide and bis(trifluoromethanesulfonyl)imide), aiming to elucidate the unique features of OEMs and its synergy with salt anions. Results show that LTPA suffers from poor electronic conductivity in polymer electrolytes, while parasitic side reactions and cointercalation of low-molecular-weight compounds handicap neat graphite materials. Surprisingly, blended composite electrodes comprising graphite and a small portion of LTPA exhibit higher Coulombic efficiency and better capacity retention over continuous cycles, with significant improvement in the electrochemical utilization degree of graphite. The synergy between OEMs and classic graphite electrode materials in polymer electrolytes may spur the architectural design of solid-state batteries, and promote the realization of more sustainable battery technology in the near future.

Investigating the impact of solid electrolyte particle size/void shape in modulating lithium-ion conduction pathways within graphite composite electrodes using in situ X-ray computed tomography

Non-invasive assays for protein biomarkers of cancer allow both its early diagnosis and continuous treatment monitoring. Yet, accurate point-of-care (POC) diagnostic devices for cancer diagnosis and monitoring, needed in point-of-care (POC) sites and places with limited resources, are scarce, not the least, due to their high current cost or bulky equipment necessary for analysis. Here, we show that the capacitive cellulase-linked electrochemical enzyme-linked aptamer-sorbent assay (e-ELASA) on magnetic beads (MBs) performed with airbrushed graphite (Gr) electrodes accurately and economically detects HER-2/neu, the protein biomarker of some aggressive forms of cancers and target of anticancer therapy. The disposable Gr electrodes were produced by airbrushing inexpensive graphite-powder/chitosan water inks onto polyester transparency films, producing high-capacitance electrodes, whose apparent specific capacitance ranged between 3.61 and 8.88mFcm-2 as a function of the number of sprayed layers and graphite content in inks. The five-layer electrodes produced from 1.7g of graphite powder (per 5mL)/0.55% chitosan water inks outperformed manually polished spectroscopic Gr electrodes earlier used in this label-free capacitive e-ELASA, as a result of the higher capacitive changes of the former, providing the same 0.1fM limit of detection of HER-2/neu, in both buffer and 10% serum, yet with a three-fold higher sensitivity. The portable and low cost airbrushed electrodes/e-ELASA set-up can be used for quick and accurate regular POC monitoring of HER-2/neu, particularly, in low and middle income settings, and, in perspective, the high-capacitance airbrushed electrodes can be adapted for other type label-free capacitive bioassays.