Search

In the realm of electrochemical nitrite detection, the potent oxidizing nature of nitrite typically necessitates operation at high detection potentials. However, this study introduces a novel approach to address this challenge by developing a highly sensitive electrochemical sensor with a low reduction detection potential. Specifically, a copper metal nanosheet/carbon paper sensitive electrode (Cu/CP) was fabricated using a one-step electrodeposition method, leveraging the catalytic reduction properties of copper's high occupancy d-orbital. The Cu/CP sensor exhibited remarkable performance in nitrite detection, featuring a low detection potential of −0.05 V vs. Hg/HgO, a wide linear range of 10~1000 μM, an impressive detection limit of 0.079 μM (S/N = 3), and a high sensitivity of 2140 μA mM−1cm−2. These findings underscore the efficacy of electrochemical nitrite detection through catalytic reduction as a means to reduce the operational voltage of the sensor. By showcasing the successful implementation of this strategy, this work sets a valuable precedent for the advancement of electrochemical low-potential nitrite detection methodologies. [ABSTRACT FROM AUTHOR]

Paper-based electrochemical sensors have the characteristics of flexibility, biocompatibility, environmental protection, low cost, wide availability, and hydropathy, which make them very suitable for the development and application of biological detection. This work proposes electrospun cellulose acetate nanofiber (CA NF)-decorated paper-based screen-printed (PBSP) electrode electrochemical sensors. The CA NFs were directly collected on the PBSP electrode through an electrospinning technique at an optimized voltage of 16 kV for 10 min. The sensor was functionalized with different bio-sensitive materials for detecting different targets, and its sensing capability was evaluated by CV, DPV, and chronoamperometry methods. The test results demonstrated that the CA NFs enhanced the detection sensitivity of the PBSP electrode, and the sensor showed good stability, repeatability, and specificity (p < 0.01, N = 3). The electrochemical sensing of the CA NF-decorated PBSP electrode exhibited a short detection duration of ∼5–7 min and detection ranges of 1 nmol mL−1–100 μmol mL−1, 100 fg mL−1–10 μg mL−1, and 1.5 × 102–106 CFU mL−1 and limits of detection of 0.71 nmol mL−1, 89.1 fg mL−1, and 30 CFU mL−1 for glucose, Ag85B protein, and E. coli O157:H7, respectively. These CA NF-decorated PBSP sensors can be used as a general electrochemical tool to detect, for example, organic substances, proteins, and bacteria, which are expected to achieve point-of-care testing of pathogenic microorganisms and have wide application prospects in biomedicine, clinical diagnosis, environmental monitoring, and food safety. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) batteries are expected to be one of the next generations of high-energy-density battery systems due to their high theoretical energy density of 2600 Wh kg−1. Embracing the trends toward flexibility, lightweight design, and cost-effectiveness, paper-based electrodes offer a promising alternative to traditional coated cathodes in Li–S batteries. Within paper-based electrodes, conductive fibers such as carbon nanotubes (CNTs) play a crucial role. They help to form a three-dimensional network within the paper matrix to ensure structural integrity over extended cycling while mitigating the shuttle effect by confining sulfur within the cathode. Herein, we explore how variously functionalized CNTs, serving as conductive fibers, impact the physical and electrochemical characteristics of paper-based sulfur cathodes in Li–S batteries. Specifically, graphitized hydroxylated carbon nanotubes (G-CNTs) exhibit remarkable capacity at low currents owing to their excellent conductivity and interaction with lithium polysulfide (LiPS), achieving the highest initial specific capacity of 1033 mAh g−1 at 0.25 C (1.1 mA cm−2). Aminated multi-walled carbon nanotubes (NH2-CNTs) demonstrate an enhanced affinity for LiPS due to the -NH2 groups. However, the uneven distribution of these fibers may induce electrode surface passivation during charge–discharge cycles. Notably, hydroxylated multi-walled carbon nanotubes (OH-CNTs) can establish a uniform and stable 3D network with plant fibers, showcasing superior mechanical properties and helping to mitigate Li2S agglomeration while preserving the electrode porosity. The paper-based electrode integrated with OH-CNTs even retains a specific capacity of approximately 800 mAh g−1 at about 1.25 C (5 mA cm−2), demonstrating good sulfur utilization and rate capacity compared to other CNT variants. [ABSTRACT FROM AUTHOR]

The effective integration of nanomaterials with underlying current collectors is a key factor affecting the performance of nonenzymatic glucose sensors, where an inappropriate integration structure often leads to poor electron transport and instability. In this work, a seamless integrated electrode was constructed by the in situ immobilizing of a nickel-based metal-organic framework (Ni-MOF) on a three-dimensional (3D) conductive nickel foam (NF) for highly sensitive and durable glucose sensing. Facilitated by a rapid microwave-assisted reaction, a robust interfacial interaction between the Ni-MOF and the substrate was established through in situ conversion from nickel oxide (NiO). The fabricated Ni-MOF/NF electrode exhibits an excellent limit of detection (LOD) of 2.65 μM and an impressive sensitivity (14.31 mA cm-2 mM-1) within the linear range (4-576 μM), which is significantly boosted compared with that of an electrode prepared by a typical drop-casting method (3.56 mA cm-2 mM-1 in 4-1836 μM). Characterization and electrochemical tests reveal that this integrated structure on the one hand contributes to fast electron transport and thus has enhanced sensitivity and on the other hand leads to exceptional durability with its structural integrity maintained under bending, shaking, and ultrasonication. Moreover, this seamless integration method was also employed to immobilize the Ni-MOF converted from the pre-chemically deposited NiO layer on another type of substrate, 3D carbon paper (CP), demonstrating the versatility of this facile strategy in creating diverse electrochemical electrodes for applications beyond glucose sensing. [ABSTRACT FROM AUTHOR]

A novel electrochemical sensor for paraquat determination was facilely developed using nanocomposites of cellulose incorporated with manganese oxide (MnO2@cellulose) modified screen-printed carbon electrode (SPCE). In this study, SPCE was fabricated on a low-cost poster paper, and nanocellulose from sugarcane bagasse was employed to enhance the electrode's surface area and improve the dispersion of MnO2. The MnO2@cellulose modified poster-SPCE exhibited a high electrochemical response toward paraquat. Various influencing factors, including differential pulse voltammetric parameters and accumulation time, were systematically explored. Under the optimal conditions, the cathodic peak current was linearly proportional to paraquat concentration in a range of 2 to 200 µM, featuring a low detection limit of 1 µM. The proposed sensor offers cost-effectiveness and can be readily prepared via a simple procedure. Moreover, this method exhibits excellent reproducibility, high selectivity, and a short analysis time. The portable electrochemical sensor was able to determine paraquat in water samples with acceptable recoveries from 95.45 to 109.20%, indicating that the sensor based on MnO2@cellulose/SPCE is reliable for paraquat quantification. [ABSTRACT FROM AUTHOR]

The New Journal of Chemistry, published by The Royal Society of Chemistry and the Centre National de la Recherche Scientifique, contains a variety of articles on different topics in chemistry. The articles cover areas such as polydimethylsiloxane coatings, water oxidation, lithium-ion batteries, and photocatalytic reactions. The journal provides valuable insights for those interested in chemistry and covers a diverse range of research areas. The document is a list of research papers published in the journal Chemistry in 2024, including topics such as the electrocatalytic degradation of tetracycline, the construction of a supramolecular system for imaging nematic mesophase and nematode cells, insights into hydrogen bond strengths in microhydrated clusters, and the development of macrophage-red blood cell hybrid membranes for eliminating pathogens, endotoxins, and heavy metal ions from blood. [Extracted from the article]

The fabrication of the Screen‐Printed Electrode (SPE) was performed using the graphite ink to print the working (WE) and counter electrodes (CE), and silver/silver chloride path as reference electrode (RE). All the electrodes are printed in a paper substrate using screen‐printing technique. The resulting SPE is characterized using scanning electron microscopy, showing all the ink layer, and subsequently optimized. The paper sample presented the cellulose fibers entanglement, extremely rough, with highly porous network. Then the graphite ink was deposited and the surface became flat, thinner and very smooth. When the silver ink was painted on top of the graphite ink, the spherical silver particles, ranged from 2–3.5 μm in size, were observed. And finally, the silver ink was covered with a AgCl layer and the particle size becomes larger with an irregular sphere‐like phase. The images showed that the layers appear to be homogeneously distributed with good coverage. Then fabrication process was optimized concerning type of paper, the sanding process, the hydrophobic barrier, the electrode design and size. In summary, the optimized values included using the previously sanded matte paper with a mineral spirit layer. The design and size of the electrode were also tested to achieve the best electrochemical performance (design 3 with 3.5 cm). The final SPE was a miniaturized and flexible paper‐based electrochemical electrode. In order to evaluate the electrical properties, the ohmic resistance of each ink was tested using a multimeter and the obtained values were 2.18 kΩ for the graphite ink, 2.27 Ω for the silver ink and 38.33 kΩ for the silver/silver chloride ink. That can indicate the good conductivity of each ink used in the fabrication of the electrode and the correct deposition of Ag/AgCl. Finally, the electrode was used to measure the electrochemical response of K4[Fe(CN)6] in different concentrations. Then a calibration curve was obtained from the voltammograms and a linearity was observed between the current and concentration in the range of 0.50–2.00 mM. That indicates that the SPE has potential to be used as a voltammetric electrode. [ABSTRACT FROM AUTHOR]

The need for disposable, simpler, and accurate paper‐based analytical devices represents an open research field that is focused on simpler fabrication methods. To achieve this, four feasible methodologies are proposed for the direct printing of an electrochemical sensor on a biodegradable paper substrate using commercial gold and silver inks, which are compatible with inkjet printing technology. Four substrate treatment strategies are evaluated: printing the active elements directly on the hydrophilic bare paper, a hydrophobic gas‐phase coating over all the substrate, a hydrophobic silane ink that is selectively printed on the paper, and a hydrophobic coating that is selectively printed and blocks the surface porosity. Thanks to the ability of the inks to conform the cellulose fibers, the resulting working electrodes tune their electrochemical active area, showing higher active electrochemical areas when the roughness is increased. The most planar consideration is achieved blocking the paper porosity with SU‐8 and the direct printing on bare paper maximizes the electrochemical response with the smallest geometric area, with current values 2.7‐times higher than the theoretical one. Although all methods allow a functional electrochemical sensor, the highest reproducible results are accomplished with the blocked paper, consequently allowing a higher controlled and robust manufacturing approach. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) have received widespread attention for their large specific surface area, porous structure, and tunable particle size. MOFs can be utilized as precursors to prepare structurally diverse bimetallic oxides, which exhibit outstanding electrochemical properties as anode materials for lithium-ion batteries (LIBs). This paper introduces the study of MOF-derived bimetallic oxides as anode materials for LIBs, focusing on the application of MOF-derived manganese-, cobalt-, iron-, and vanadium-based bimetallic oxides in LIBs. MOF-derived bimetallic oxides, with the advantages of tunable compositions and nano-structures, are capable of further contributing to the enhancement of electrochemical performances. Finally, the problems of these derived materials in the application of LIBs are prospected, and reliable solutions and future development prospects are proposed. [ABSTRACT FROM AUTHOR]

The development of nanohybrid with high electrocatalytic activity is of great significance for electrochemical sensing applications. In this work, we develop a novel and facile method to prepare a high-performance flexible nanohybrid paper electrode, based on nitrogen-doped carbon (NC) wrapped Bi nanoparticles (Bi-NPs) assembly derived from Bi-MOF, which are decorated on a flexible and freestanding graphene paper (GP) electrode. The as-obtained Bi-NPs encapsulated by an NC layer are uniform, and the active sites are increased by introducing a nitrogen source while preparing Bi-MOF. Owing to the synergistic effect between the high conductivity of GP electrode and the highly efficient electrocatalytic activity of Bi-NPs, the NC wrapped Bi-NPs (Bi-NPs@NC) modified GP (Bi-NPs@NC/GP) electrode possesses high electrochemically active area, rapid electron-transfer capability, and good electrochemical stability. To demonstrate its outstanding functionality, the Bi-NPs@NC/GP electrode has been integrated into a handheld electrochemical sensor for detecting heavy metal ions. The result shows that Zn2+, Cd2+, and Pb2+ can be detected with extremely low detection limits, wide linear range, high sensitivity, as well as good selectivity. Furthermore, it demonstrates outstanding electrochemical sensing performance in the simultaneous detection of Zn2+, Cd2+, and Pb2+. Finally, the proposed electrochemical sensor has achieved excellent repeatability, reproducibility, stability, and reliability in measuring real water samples, which will have great potential in advanced applications in environmental systems. [ABSTRACT FROM AUTHOR]

This study investigates nitrogen-doped carbon synthesis and electrochemical properties as electrode material for energy storage devices, an additional focus of the work is on the electrochemical exfoliation synthesis of nitrogen-doped carbon using various precursors and doping methods. The physical properties of the synthesized sample are characterized using X-ray photoelectron spectroscopy, scanning electron microscopy, and Raman spectroscopy. The electrochemical properties of the N-doped carbons are studied using cyclic voltammetry and galvanostatic charge-discharge cycling. Finally, the work explores the potential application of the N-doped carbons as electrode material for energy storage devices, such as supercapacitors. The results show that N-doped carbons exhibit electrochemical performance superior to that of graphene oxide, with higher electrical capacitance. The results demonstrate the potential of N-doped carbons as high-performance electrode materials for electrochemical energy storage applications. This paper aims to explain the advantages of N-doping in carbon materials more precisely in graphene and the use of these materials in creating electrodes for application in supercapacitors and batteries. [ABSTRACT FROM AUTHOR]

Ni-rich Li(NixCoyMnz)O2 (x ≥ 0.8)-layered oxide materials are highly promising as cathode materials for high-energy-density lithium-ion batteries in electric and hybrid vehicles. However, their tendency to undergo side reactions with electrolytes and their structural instability during cyclic lithiation/delithiation impairs their electrochemical cycling performance, posing challenges for large-scale applications. This paper explores the application of an Al2O3 coating using an atomic layer deposition (ALD) system on Ni-enriched Li(Ni0.8Co0.1Mn0.1)O2 (NCM811) cathode material. Characterization techniques, including X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, were used to assess the impact of alumina coating on the morphology and crystal structure of NCM811. The results confirmed that an ultrathin Al2O3 coating was achieved without altering the microstructure and lattice structure of NCM811. The alumina-coated NCM811 exhibited improved cycling stability and capacity retention in the voltage range of 2.8–4.5 V at a 1 C rate. Specifically, the capacity retention of the modified NCM811 was 5%, 9.11%, and 11.28% higher than the pristine material at operating voltages of 4.3, 4.4, and 4.5 V, respectively. This enhanced performance is attributed to reduced electrode–electrolyte interaction, leading to fewer side reactions and improved structural stability. Thus, NCM811@Al2O3 with this coating process emerges as a highly attractive candidate for high-capacity lithium-ion battery cathode materials. [ABSTRACT FROM AUTHOR]

Laser irradiation to induce networks of graphene-based structures toward cost-effective, flexible device fabrication is a highly pursued area, with applications in various polymeric substrates. This work reports the application of this approach toward commonly available, eco-friendly, low-cost substrates, namely, chromatographic and office papers. Through an appropriate chemical treatment with sodium tetraborate as a fire-retardant agent, photothermal conversion to porous laser-induced graphene (LIG) on paper is achieved. Raman peaks are identified, with I2D/IG and ID/IG peak ratios of 0.616 ± 0.095 and 1.281 ± 0.173, showing the formation of multilayered graphenic material, exhibiting sheet resistances as low as 56.0 Ω sq-1. Coplanar, LIG-based, three-electrode systems (working, counter and reference electrodes) are produced and characterized, showing high current Faradaic oxidation and reduction peaks, translating in high electrochemical active area, doubling the geometric area. Good electron transfer kinetics performed exclusively with on-chip measurements are reached, with k0 values as high as 7.15 x 10-4 cm s-1. Proof-of-concept, amperometric, enzymatic glucose biosensors are developed, exhibiting good analytical performance in physiologically relevant glucose levels, with results pointing to the applicability of paper-based LIG toward efficient, disposable electrochemical sensor development, increasing their sustainability and accessibility, while simplifying their production and reducing their cost. [ABSTRACT FROM AUTHOR]

A proton exchange membrane fuel cell (PEMFC) is an efficient and environmentally friendly power production technology that uses hydrogen energy. The cathodic oxygen reduction electrode is a critical component in the development of PEMFC. Most techniques deposit catalyst nanoparticles in areas that are inaccessible for catalytic processes, reducing platinum utilization. The substrate used in this study was carbon paper (CP) with a self-supporting structure. First, electrochemical acidification technology was employed to modify the CP's surface, followed by nanoparticle manufacturing and fixation on the CP in a single step by electrodeposition. The Pt/C0.5V2.24CP catalyst electrode demonstrated high-quality activity in the oxygen reduction reaction (ORR), with a homogeneous particle dispersion and particle size of around 50 nm. The mass activity and electrochemical active surface area (ECSA) of the Pt/C0.5V2.24CP catalyst electrode were 1.74 and 3.98 times higher than those of the Pt/C/CP-1 electrodes made with commercial catalysts, respectively. After 5000 cycles of accelerated durability testing (ADT), the mass activity and ECSA were 1.28 times and 6.16 times more than Pt/C/CP-1. This paper successfully proved the viability of electrodepositing Pt nanoparticles on CP following acidification, and that the electrochemical acidification methods have a positive influence on improving electrode ORR activity. [ABSTRACT FROM AUTHOR]

Current 3D printed electrodes suffer from insufficient multiscale transport speed, which limits the improvement of electrochemical performance of 3D printed electrodes. Herein, a bioinspired hierarchical fast transport network (HFTN) in a 3D printed reduced graphene oxide/carbon nanotube (3DP GC) electrode demonstrating superior electrochemical performance is constructed. Theoretical calculations reveal that the HFTN of the 3DP GC electrode increases the ion transport rate by more than 50 times and 36 times compared with those of the bulk GC electrode and traditional 3DP GC (T‐3DP GC) electrode, respectively. Compared with carbon paper, carbon cloth, bulk GC electrode, and T‐3DP GC electrode, the HFTN in 3DP GC electrode endows obvious advantages: i) efficient utilization of surface area for uniform catalysts dispersion during electrochemical deposition; ii) efficient utilization of catalysts enables the high mass activity of catalysts and low overpotential of electrode in electrocatalytic reaction. The cell of 3DP GC/Ni‐NiO||3DP GC/NiS2 demonstrates a low voltage of only 1.42 V to reach 10 mA cm−2 and good stability up to 20 h for water splitting in alkaline conditions, which is superior to commercialized Pt/C||RuO2. This work demonstrates great potential in developing high‐performance 3D printed electrodes for electrochemical energy conversion and storage. [ABSTRACT FROM AUTHOR]

The prevalence of polyfluoroalkyls and perfluoroalkyls (PFAS) represents a significant challenge, and various treatment techniques have been employed with considerable success to eliminate PFAS from water, with the ultimate goal of ensuring safe disposal of wastewater. This paper first describes the most promising electrochemical oxidation (EO) technology and then analyses its basic principles. In addition, this paper reviews and discusses the current state of research and development in the field of electrode materials and electrochemical reactors. Furthermore, the influence of electrode materials and electrolyte types on the deterioration process is also investigated. The importance of electrode materials in ethylene oxide has been widely recognised, and therefore, the focus of current research is mainly on the development of innovative electrode materials, the design of superior electrode structures, and the improvement of efficient electrode preparation methods. In order to improve the degradation efficiency of PFOS in electrochemical systems, it is essential to study the oxidation mechanism of PFOS in the presence of ethylene oxide. Furthermore, the factors influencing the efficacy of PFAS treatment, including current density, energy consumption, initial concentration, and other parameters, are clearly delineated. In conclusion, this study offers a comprehensive overview of the potential for integrating EO technology with other water treatment technologies. The continuous development of electrode materials and the integration of other water treatment processes present a promising future for the widespread application of ethylene oxide technology. [ABSTRACT FROM AUTHOR]

High-throughput materials research is strongly required to accelerate the development of safe and high energy-density lithium-ion battery (LIB) applicable to electric vehicle and energy storage system. The artificial intelligence, including machine learning with neural networks such as Boltzmann neural networks and convolutional neural networks (CNN), is a powerful tool to explore next-generation electrode materials and functional additives. In this paper, we develop a prediction model that classifies the major composition (e.g., 333, 523, 622, and 811) and different states (e.g., pristine, pre-cycled, and 100 times cycled) of various Li(Ni, Co, Mn)O2 (NCM) cathodes via CNN trained on scanning electron microscopy (SEM) images. Based on those results, our trained CNN model shows a high accuracy of 99.6% where the number of test set is 3840. In addition, the model can be applied to the case of untrained SEM data of NCM cathodes with functional electrolyte additives. [ABSTRACT FROM AUTHOR]

This paper describes the process to obtain ceramic nanotubes from titanium dioxide, alumina and yttrium oxide by a feasible, replicable and reliable technology, including three stages, starting from an electrospinning process of poly(methyl methacrylate) solutions. A minimum diameter of 0.3 μm was considered optimal for PMMA nanofibers in order to maintain the structural stability of covered fibers, which, after ceramic film deposition, leads to a fiber diameter of 0.5–0.6 μm. After a chemical and physical analysis of the stages of obtaining ceramic nanotubes, in all cases, uniform deposition of a ceramic film on PMMA fibers and, finally, a uniform structure of ceramic nanotubes were noted. The technological purpose was to use such nanotubes as ingredients in screen-printing inks for electrochemical sensors, because no study directly targeted the subject of ceramic nanotube applications for printed electronics to date. The printing technology was analyzed in terms of the ink deposition process, printed electrode roughness vs. type of ceramic nanotubes, derived inks, thermal curing of the electrodes and the conductivity of electrodes on different support (rigid and flexible) at different curing temperatures. The experimental inks containing ceramic nanotubes can be considered feasible for printed electronics, because they offer fast curing at low temperatures, reasonable conductivity vs. electrode length, good printability on both ceramic or plastic (flexible) supports and good adhesion to surface after curing. [ABSTRACT FROM AUTHOR]

This paper describes a Ag/AgCl electrochemical electrode for marine electric field measurements, which was prepared by depositing silver chloride on a silver foil substrate using double-pulse electrodeposition. The impact of positive direction peak current density and deposition time on electrode performance in the preparation of Ag/AgCl electrodes through double-pulse electrodeposition was investigated. Scanning electron microscopy and voltammetry have been used to study the properties of the prepared electrodes. This work reveals the correlation between the electrochemical behavior of electrodes and the physical properties of their surfaces, especially specific surface area and porosity. The study verified the characteristics of Ag/AgCl marine electric field electrodes obtained with different pulse parameters by analyzing the potential stability and noise level of the electrode in salt water. The study's results have positive significance for improving the accuracy of marine electric field measurements. [ABSTRACT FROM AUTHOR]

Heterogeneous interface construction is of far-reaching significance to optimize the electrochemical performance of electrodes. Herein, a multi-step alternating electrochemical deposition (MAED) method is proposed to alternately deposit Co0.85Se and Ni3S4 nanosheets on a nickel foam (NF), forming a special alternate layer-by-layer structure with multi-layered heterogeneous interfaces. The creation of the multi-layered heterogeneous interfaces provides a large interfacial area for redox reactions with optimum interstitials facilitating ion diffusion, thus greatly improving the electrochemical energy storage efficiency. With the increase in the layer number, the material exhibits increasingly better energy storage performance, and 8L-Co0.85Se@Ni3S4/NF exhibits the highest specific capacitances of 2508 F g−1 and 1558 F g−1 at a scan rate of 2 mV s−1 and a current density of 1 A g−1. The 8L-Co0.85Se@Ni3S4/NF//polypyrrole (PPy)/NF asymmetric supercapacitor provides a maximum operation potential window of 1.55 V and energy densities of 76.98 and 35.74 W h kg−1 when the power densities are 775.0 and 15 500 W kg−1, respectively, superior to most of the related materials reported. Through MAED, the deposited phase and the layer number can be accurately controlled, thus providing an efficient strategy for interface construction so as to increase the electrochemical activity of the energy storage materials. [ABSTRACT FROM AUTHOR]

It was precisely because LiNi 0. 5 Mn 1. 5 O4 cathode material had many advantages, including high voltage, high power, no pollution, low cost, etc., that it became a research hotspot for lithium-ion cathode materials. Although LiNi 0. 5 Mn 1. 5 O4 has a three-dimensional Li + diffusion channel, there are still some problems that lead to capacity decay and reduced cycling stability, limiting its commercial application. In this paper, the LiNi 0. 5 Mn 1. 5 O4 cathode material was prepared by the freezing precipitation method. We studied the effects of different drying methods, such as blast drying, water bath drying and freeze-drying on the structure, morphology and electrochemical properties of LiNi 0. 5 Mn 1. 5 O4 cathode materials. The study found that the LiNi 0. 5 Mn 1. 5 O4 cathode material prepared by the precipitation-freeze-drying method had a complete crystal form, a stable structure and no LixNi 1 − x O impurity peak. The SEM image showed that the particles were smaller and had a smooth surface. The initial discharge-specific capacity at 0.1 C was 105.2 mAh⋅g − 1 . After 50 cycles, its specific discharge capacity was 99.4 mAh⋅g − 1 and the capacity retention rate was 94.5%. Compared with LiNi 0. 5 Mn 1. 5 O4 materials prepared by other methods, it had better electrochemical performance. [ABSTRACT FROM AUTHOR]

3D printing has attracted the interest of researchers due to its creative freedom, low cost, and ease of operation. Because of these features, this technology has produced different types of electroanalytical platforms. Despite their popularity, the thermoplastic composites used for electrode fabrication typically have high electrical resistance, resulting in devices with poor electrochemical performance. Herein, we propose a new strategy to improve the electrochemical performance of 3D-printed electrodes and to gain chemical selectivity towards glucose detection. The approach involves synthesising a nanostructured gold film using an infrared laser source directly on the surface of low-contact resistance 3D-printed electrodes. The laser parameters, such as power, focal distance, and beam scan rate, were carefully optimised for the modification steps. Scanning electronic microscopy and energy-dispersive X-ray spectroscopy confirmed the morphology and composition of the nanostructured gold film. After modification, the resulting electrodes were able to selectively detect glucose, encouraging their use for sensing applications. When compared with a gold disc electrode, the gold-modified 3D-printed electrode provided a 44-fold current increase for glucose oxidation. As proof of concept, the devices were utilised for the non-enzymatic catalytic determination of glucose in drink samples, demonstrating the gold film's catalytic nature and confirming the analytical applicability with more precise results than commercial glucometers. [ABSTRACT FROM AUTHOR]

Recent research on supercapacitors (SCs) has been attractive due to the potential application in a variety of fields related to energy storage. Electrode materials play a very important role for the performance of SCs and various metal nanoparticles are involved in the SC electrodes. In this paper, the roles of metal nanoparticles for SCs are reviewed and discussed. They can serve as a dopant to modify the surface of electrode materials, or be embedded in a composite to effectively reduce the resistance and lead to an enhanced specific capacitance. Some metal nanoparticles can be also employed as electrode materials directly, but easily being oxidized. Metallic nanoparticles can even act as current collectors, especially for these noble metals with excellent stability and high conductivity. Nanoporous metals prepared by dealloying and electrochemical method can be used as both pseudocapacitive materials and current collector of SCs. Some important experimental data on this issue are summarized. A brief discussion on the future directions, challenges and opportunities in this topic is also provided. [ABSTRACT FROM AUTHOR]

Electrochemical machining (ECM) is one of the most ideal machining methods for difficult-to-cut material of U71Mn alloy. Therefore, it is vital to obtain the electrochemical characteristics of the material. In this paper, these characteristics are measured with an electrochemical station, and a series of experiments are conducted to verify them. The electrolyte solutions of 15 wt.% NaNO3 and 15 wt.% NaCl are selected for the experiments. The polarization experimental results indicate a broader range of passive regions in the NaNO3 electrolyte solution compared with that in the NaCl. This means that a higher voltage is required to break down the passive film in ECM experiments. Meanwhile, the current efficiency of the alloy is measured in 15 wt.% NaNO3 and 15 wt.% NaCl. The results indicate that the current efficiency of U71Mn alloy in NaCl electrolyte solution is higher than that in NaNO3 electrolyte solution. The electrochemical characteristics of U71Mn alloy are verified with a series of single-factor experiments, and reasonable machining parameters are obtained. The suitable range of machining voltage is 10 to 20 V, and the range of inter-electrode gap is 0.1 to 0.2 mm in these two electrolyte solutions. Finally, multi-parameter experiments are carried out in these two electrolyte solutions to obtain machining samples. The experimental results show that 15 wt.% NaNO3 proved to be a better electrolyte solution for U71Mn alloy, the surface roughness (SR) of the workpiece is Sa 0.72 μm, and the material removal rate (MRR) is 0.096 g/min. [ABSTRACT FROM AUTHOR]

In recent years, cobalt sulfide has become a potential electrode material due to its considerable theoretical capacitance and high conductivity. However, its agglomerate susceptibility and structural instability during the charging/discharging process have impeded its widespread application. Herein, we synthesize Co9S8/MXene nanohybrids using a straightforward one-step solvothermal method, employing MXene nanosheets as a conducting substrate. The strong interfacial interaction of both phases is exploited to efficiently alleviate the above problems. Furthermore, a metal-doped strategy has been adopted to modulate the composition and the structure of the nanocomposites, which could expose more redox active sites and considerably improve the redox kinetics. The obtained Al–Co9S8/MXene material has a remarkable electrical conductivity and excellent charge/discharge performance, with the specific capacitance up to 1657.33 F g−1 at 2 A g−1 and a superior rate capability of 75% retention even at 12 A g−1. This strategy not only provides an efficient method for synthetic anode electrode materials but also offers ideas for the development of materials more suitable for industrial applications. [ABSTRACT FROM AUTHOR]

In this research, we explore the utilization of biomass-derived proteins, specifically from egg whites, as a novel carbon source for crafting silicon/nitrogen-doped carbon composites, aimed at overcoming the significant volume expansion issues associated with silicon electrode materials in lithium-ion batteries (LIBs). Egg whites, known for their high protein content, offer a sustainable reservoir of carbon and nitrogen, essential for enhancing the electrochemical performance of silicon-based electrodes. Leveraging the unique structural transformation induced by whipping egg whites—resulting in a foamy material with distinct properties—we blend this with micron-sized silica powder. This mixture is then subjected to a straightforward carbonization process, yielding silicon–carbon composites enveloped in nitrogen-doped amorphous carbon layers. Our findings demonstrate that these Si–N–PC composites, when used as anodes in LIBs, deliver a commendable reversible capacity of 814 mA h g−1 over 100 cycles at a current density of 1 A g−1. The incorporation of nitrogen-doped carbon layers significantly improves lithium-ion diffusion, mechanical stability, and overall electrochemical performance of the electrode material. This approach not only simplifies the production process but also aligns with environmentally friendly practices. Given these results, we posit that our method could serve as a viable blueprint for the mass production of next-generation energy materials, addressing both performance and sustainability concerns. [ABSTRACT FROM AUTHOR]

Graphene is extremely sensitive to its surrounding environment. In fact, any modification on its surface, such as an adsorption of a molecule, can change its properties. The conductivity of graphene is a crucial parameter to be examined for potential graphene-based applications, especially biosensors. In this paper, we have investigated the effects of non-covalent functionalization based on π–π interaction, using 1-pyrenebutyric acid N-hydroxysuccinimide ester (PBASE), on the conductivity of graphene-based electrodes by electrochemical techniques. Graphene layers were obtained by chemical vapor deposition (CVD) and characterized by Raman spectroscopy, Scanning Electron Microscopy (SEM), and X-Ray Diffraction (XRD). The results demonstrate the synthesis of a high quality and continuous monolayer graphene with an I2D/IG ratio = 2.71 and ID = 0. After the functionalization of graphene-based electrode with PBASE, the electrochemical analyses confirmed a p-doping effect existence influencing the conductivity by increasing the charge transfer resistance Rct from 816.5 to 2213 Ω. Furthermore, increasing the concentration of PBASE from 5 mM to 10 mM did not affect the conductivity as the Rct did not change. Solvent adsorption was found to be the main cause of the decrease in conductivity during the functionalization process. This study highlights the effect of non-covalent π-π stacking of PBASE on graphene to tune the electrical properties of graphene through functionalization processes for a better performance for their use as biosensors. [ABSTRACT FROM AUTHOR]

The interfacial effect is important for anodes of transition metal dichalcogenides (TMDs) to achieve superior lithium-ion storage performance. In this paper, a MoS2/FeS2 heterojunction is synthesized by a simple hydrothermal reaction to construct the interface effect, and the heterostructure introduces an inherent electric field that accelerates the de-embedding process of lithium ions, improves the electron transfer capability, and effectively mitigates volume expansion. XPS analysis confirms evident chemical interaction between MoS2 and FeS2 via an interfacial covalent bond (Mo–S–Fe). This MoS2/FeS2 anode shows a distinct interfacial effect for efficient interatomic electron migration. The electrochemical performance demonstrated that the discharge capacity can reach up to 1217.8 mA h g−1 at 0.1 A g−1 after 200 cycles, with a capacity retention rate of 72.9%. After 2000 cycles, the capacity retention is about 61.6% at 1.0 A g−1, and the discharge capacity can still reach 638.9 mA h g−1. Electrochemical kinetic analysis indicated an enhanced pseudocapacitance contribution and that the MoS2/FeS2 had sufficient adsorption of lithium ions. This paper therefore argues that this interfacial engineering is an effective solution for designing sulfide-based anodes with good electrochemical properties. [ABSTRACT FROM AUTHOR]

Electrochemical dilatometry is used to investigate Li plating/stripping on Cu foil and porous carbon paper substrates. Experiments are performed in standard electrolyte for Li–S batteries at a current density of 1 mA cm−2 with a Li plating charge fixed at 1 mAh cm−2. A fully dense Li film (4.8 μm thick) is initially electrodeposited on the Cu electrode. However, from the 2nd Li plating/stripping cycle, Li deposit becomes porous to reach a thickness of 9.6 µm at the 27th cycle, corresponding to a film porosity of 50%, favoring its collapse during the subsequent cycles. When a carbon paper with a low surface area (0.02 m2 g−1) is used as a substrate, Li deposition occurs preferentially in the pores of the carbon paper during the first few cycles. However, this does not prevent the formation of Li dendrites, which progressively extend on the top of the substrate, resulting in the degradation of the electrode cyclability after about 40 cycles. The use of a carbon paper with a higher surface area (4.2 m2 g−1) favors Li deposition inside the electrode, with no apparent loss of cyclability after 50 cycles. However, this does not prevent the formation of dead Li, as suggested by the continuous and irreversible expansion of the electrode over cycling at a mean rate of 1.3 μm per cycle. Additionally, a large and irreversible expansion of 38 μm is observed during the first cycle, which is attributed to the lithium-solvent co-intercalation in the graphitic part of the carbon paper substrate. [ABSTRACT FROM AUTHOR]

Electrode‐assisted techniques are well suited for the separation of ions from solutions with reduced energy and chemical consumption. This emerging platform can benefit greatly from the convection enhanced and zero‐gap reactor designs unlocked by macroporous electrodes, but immobilizing ion‐selective layers on such complex 3D architectures is challenging. Electropolymerization of conductive polymers is proposed as a coating methodology to fabricate highly conformal coatings with electrochemically switchable ion‐exchange functionality. To demonstrate this, the synthetic parameters, resulting morphology, and ionic separation performance of poly(3,4‐ethylenedioxythiophene) (PEDOT) on commercially available carbon paper electrodes are studied. Electropolymerization of PEDOT in organic solvents results in rougher morphologies with high sensitivity to electrochemical protocols employed. When polymerized in aqueous solutions of poly(4‐styrenesulfonate) (PSS−), the resulting PEDOT/PSS blend polymer forms smooth coatings with a controllable thickness down to 0.1 µm. With appropriate voltage bias, PEDOT/PSS coated electrodes can take up and release Ni2+ in the presence of excess Na+. Increasing the coating thickness decreases the adsorption capacity due to mass transfer limitations, and the maximum adsorption capacity for Ni2+ is reached for the thinnest coatings at 228 mg g−1. Through a systematic study of PEDOT/PSS coated carbon paper, electropolymerization is identified to be a promising avenue for porous electrode functionalization. [ABSTRACT FROM AUTHOR]

Electrode‐assisted techniques are well suited for the separation of ions from solutions with reduced energy and chemical consumption. This emerging platform can benefit greatly from the convection enhanced and zero‐gap reactor designs unlocked by macroporous electrodes, but immobilizing ion‐selective layers on such complex 3D architectures is challenging. Electropolymerization of conductive polymers is proposed as a coating methodology to fabricate highly conformal coatings with electrochemically switchable ion‐exchange functionality. To demonstrate this, the synthetic parameters, resulting morphology, and ionic separation performance of poly(3,4‐ethylenedioxythiophene) (PEDOT) on commercially available carbon paper electrodes are studied. Electropolymerization of PEDOT in organic solvents results in rougher morphologies with high sensitivity to electrochemical protocols employed. When polymerized in aqueous solutions of poly(4‐styrenesulfonate) (PSS−), the resulting PEDOT/PSS blend polymer forms smooth coatings with a controllable thickness down to 0.1 µm. With appropriate voltage bias, PEDOT/PSS coated electrodes can take up and release Ni2+ in the presence of excess Na+. Increasing the coating thickness decreases the adsorption capacity due to mass transfer limitations, and the maximum adsorption capacity for Ni2+ is reached for the thinnest coatings at 228 mg g−1. Through a systematic study of PEDOT/PSS coated carbon paper, electropolymerization is identified to be a promising avenue for porous electrode functionalization. [ABSTRACT FROM AUTHOR]

This paper discusses the electrochemical properties of thin-film, planar, titanium–platinum (Ti-Pt) microelectrodes fabricated using glass or silicon substrates and compares their performance to the classic platinum (Pt) microelectrodes embedded in glass. To analyze the possible differences coming both from the size of the tested electrodes as well as from the substrate, short- and long-term electrochemical tests were performed on selected water electrolytes (KCl, HCl, KOH). To study the electrochemical response of the electrodes, the cyclic voltammetry (CV) measurements were carried out at different scanning rates (from 5 to 200 mV/s). Long-term tests were also conducted, including one thousand cycles with a 100 mV/s scan rate to investigate the stability of the tested electrodes. Before and after electrochemical measurements, the film morphology was analyzed using a scanning electron microscope (SEM). The good quality of the thin-film Pt electrodes and the high repeatability in electrochemical response have been shown. There are minor differences in standard deviation values taken from electrochemical measurements, comparing thin-film and wire-based electrodes. Damages or any changes on the electrodes' surfaces were revealed by SEM observations after long-term electrochemical tests. [ABSTRACT FROM AUTHOR]

In this paper, La-doped Ti/SnO2-Sb2O4 electrode was prepared by electrodeposition and used for electrochemical degradation of rhodamine B. The optimum preparation conditions of the electrode were optimized as deposition time of 15 min and calcination at 500 ℃ for 2 h. The water treatment conditions were selected as initial pH 3.0, electrolyte Na2SO4 concentration 0.1 M, current density 30 mA cm−2, and initial rhodamine B concentration 20 mg L−1; the color and TOC removal of RhB reached 99.78% and 82.41% within 30 min. The FESEM, XRD, XPS, CV, LSV, and EIS characterization studies demonstrated that Ti/SnO2-Sb2O4-1%La electrode had a dense structure and the highest oxygen evolution potential (2.14 V) and lowest charge transfer resistance (0.198 Ω cm−2), indicating that doped La has lower energy consumption. Moreover, La doping can expand the specific surface area, active site, performance of pollutant degradation, and service life of the electrode. Especially, the service life of Ti/SnO2-Sb2O4-1%La is increased by three times, and the maximum life span reaches 90 min (1000 mA cm−2, 1 M H2SO4). Free radical quenching experiments show that ·OH plays a major role in the degradation of RhB. The Ti/SnO2-Sb2O4-1%La electrode prepared in this paper and its results will provide data support and reference for the design of efficient electrocatalytic electrode. [ABSTRACT FROM AUTHOR]

Pholcodine, an anti-tussive medication widely used as an over-the-counter, OTC drug, has recently faced restrictions in several countries. This paper presents a sensitive electrochemical approach for pholcodine detection. The electrochemical method involved fabricating a graphene nanoplatelets electrode, incorporating polythiophene nanospheres polymer to promote electron transfer and increase the activated surface area. Characterization of the fabricated electrode was performed using transmission electron microscopy, ATR-Fourier-transform infrared spectroscopy, X-ray crystallography, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. The electrochemical behavior of pholcodine with the fabricated electrode was investigated using cyclic voltammetry, chronoamperometry, square wave voltammetry (SWV), and differential pulse voltammetry (DPV). The developed electrode led to a linear response for pholcodine ranging from 10 to 45 mg/L with detection limits of 1.41 and 1.51 mg/mL for SWV and DPV, respectively and quantification limits of 4.27 and 4.57 mg/L for SWV and DPV, respectively. The proposed method has accurately recovered pholcodine in spiked serum samples with a recovery percentage ranging from 1.2 to 2.9%. The optimized method is found to be accurate, precise, and robust by applying validation parameters provided by International Council for Harmonization. Two green metrics were computed to assess the method's greenness, the findings showed that the developed method is environmentally friendly with minimum sample preparation steps. Article highlights: Fabrication of electrochemical electrode using graphene nanoplatelets modified with polythiophene nanospheres. Voltammetric analysis of pholcodine using square wave voltammetry and differential pulse voltammetry with method validation according to International Council for Harmonization (ICH) guidelines. Assessment of the method's greenness using two green assessment tools; analytical GREEness metric (AGREE) and complementary green analytical procedure index (ComplexGAPI) software tools. [ABSTRACT FROM AUTHOR]

Ni-rich layered cathodes are deemed as a potential candidate for high-energy-density lithium-ion batteries, but their high sensitivity to air during storage and poor thermal stability are a vital challenge for large-scale applications. In this paper, distinguished from the conventional surface modification and ion doping, an effective solid-solution strategy was proposed to strengthen the surface and structural stability of Ni-rich layered cathodes by introducing Li2MnO3. The structural analysis results indicate that the formation of Li2CO3 inert layers on Ni-rich layered cathodes during storage in air is responsible for the increased electrode interfacial impedance, thereby leading to the severe deterioration of electrochemical performance. The introduction of Li2MnO3 can reduce the surface reactivity of Ni-rich cathode materials, playing a certain suppression effect on the formation of surface Li2CO3 layer and the deterioration of electrochemical performances. Additionally, the thermal analysis results show that the heat release of Ni-rich cathodes strongly depends on the charge of states, and Li2MnO3 can suppress oxygen release and significantly enhance the thermal stability of Ni-rich layered cathodes. This work provides a method to improving the storage performance and thermal stability of Ni-rich cathode materials. [ABSTRACT FROM AUTHOR]

Nowadays, lithium-ion batteries are undoubtedly known as the most promising rechargeable batteries. However, these batteries face some big challenges, like not having enough energy and not lasting long enough, that should be addressed. Ternary Ni-rich Li[NixCoyMnz]O2 and Li[NixCoyAlz]O2 cathode materials stand as the ideal candidate for a cathode active material to achieve high capacity and energy density, low manufacturing cost, and high operating voltage. However, capacity gain from Ni enrichment is nullified by the concurrent fast capacity fading because of issues such as gas evolution, microcracks propagation and pulverization, phase transition, electrolyte decomposition, cation mixing, and dissolution of transition metals at high operating voltage, which hinders their commercialization. In order to tackle these problems, researchers conducted many strategies, including elemental doping, surface coating, and particle engineering. This review paper mainly talks about origins of problems and their mechanisms leading to electrochemical performance deterioration for Ni-rich cathode materials and modification approaches to address the problems. [ABSTRACT FROM AUTHOR]

With the increasing use and the consequent retirement of lithium-ion batteries (LIBs), there has been an upsurge in spent LIBs, posing significant challenges to energy, resources, and the environment, which has led to the necessity to recycle spent LIBs. For the recovery of valuable components in cathode materials, traditional hydrometallurgical and pyrometallurgical methods are not conducive to the sustainable development of the environment, making it crucial to explore lithium-ion battery (LIB) recovery technologies beyond traditional methods. This paper focuses on introducing intensification technologies that are beyond the traditional methods, including external field intensification technologies (in the fields of acoustics, optics, electricity, and magnetism), novel solvent-based intensification technologies, direct recovery technologies, and potential development technologies. From the perspective of process intensification, the process flow, principle, effect, and scope of application of various recovery technologies are systematically summarized. Furthermore, the advantages of these advanced recovery methods and the current challenges faced by them are discussed to propose the potential research direction of the recovery technology of lithium-ion battery cathode materials, which is of significant importance for the sustainable development of the global new energy industry, the maintenance of ecological balance, and the circular utilization of mineral resources, such as lithium, nickel, and cobalt. [ABSTRACT FROM AUTHOR]

Protein preconcentration is an essential sample preparation step for analysis in which the targeted proteins exist in low concentrations, such as bodily fluids, water, or wastewater. Nonetheless, very few practical implementations of miniaturized protein preconcentration devices have been demonstrated in practice, and even fewer have been integrated with other microanalytical steps. Existing approaches rely heavily on additional chemicals and reagents and introduce complexity to the overall assay. In this paper, we propose a novel miniaturized isoelectric focusing-based protein preconcentration screening device based on electrochemically derived pH gradients rather than existing chemical reagent approaches. In this way, we reduce the need for additional chemical reagents to zero while enabling device incorporation in a seamlessly integrated full protein analysis microsystem via Lab-on-PCB technology. We apply our previously presented Lab-on-PCB approach to quantitatively control the pH of a solution in the vicinity of planar electrodes using electrochemical acid generation through redox-active self-assembled monolayers. The presented device comprises a printed circuit board with an array of gold electrodes that were functionalized with 4-aminothiophenol; this formed a self-assembled monolayer that was electropolymerized to improve its electrochemical reversibility. Protein preconcentration was performed in two configurations. The first was open and needed the use of a holder to suspend a well of fluid above the electrodes; the second used microfluidic channels to enclose small volumes of fluid. Reported here are the resulting data for protein preconcentration in both these forms, with a quantitative concentration factor shown for the open form and qualitative proof shown for the microfluidic. [ABSTRACT FROM AUTHOR]

In this paper, a critical review of results obtained using a reticulated vitreous carbon (RVC) three-dimensional cathode for the electrochemical depletion of various divalent ions, such as Cu+2, Cd+2, Pb+2, Zn+2, Ni+2, and Co+2, often present in wastewater, has been carried out. By analyzing the kinetics and fluid dynamics of the process found in literature, a general dimensionless equation, Sh = f(Re), has been determined, describing a general trend for all the analyzed systems regardless of the geometry, dimensions, and starting conditions. Thus, a map in the log(Sh) vs. log(Re) plane has been reported by characterizing the whole ion electrochemical depletion process and highlighting the existence of a good correlation among all the results. Moreover, because in recent years, the interest in using this three-dimensional cathode material seems to have slowed, the intent is to revive it as a useful tool for metal recovery, recycling processes, and water treatments. [ABSTRACT FROM AUTHOR]

Pt-based electrochemical ammonia-nitrogen sensors played a significance role in real-time monitoring the ammonia-nitrogen concentration. The alloying of Pt and transition metals was one of the effective ways to increase the detectability of the sensitive electrode. In this paper, a self-supported electrochemical electrode for the detection of ammonia nitrogen was obtained by the electrodeposition of PtNi alloy nanoleaves on a carbon cloth (PtNi-CC). Experimental results showed that the PtNi-CC electrode exhibited enhanced detection performance with a wide linear range from 0.5 to 500 µM, high sensitivity (7.83 µA µM−1 cm−2 from 0.5 to 150 μM and 0.945 µA µM−1 cm−2 from 150 to 500 μM) and lower detection limit (24 nM). The synergistic effect between Pt and Ni and the smaller lattice spacing of the PtNi alloy were the main reasons for the excellent performance of the electrode. This work showed the great potential of Pt-based alloy electrodes for the detection of ammonia-nitrogen. [ABSTRACT FROM AUTHOR]

This paper develops a coupling model of the relationship between chemical reaction, temperature and stress/strain for Li (Ni0.6Mn0.2Co0.2) O2 cathode materials. With the process of reaction, the concentration of electrolyte salt changes rapidly at the beginning of diffusion and tends to dynamic equilibrium. The concentration of electrolyte LiPF6 in electrode materials diffuses from bottom to top with the process of lithium intercalation. In the process of Li-ion intercalation, the temperature rise of porous electrode materials increases sharply at first, then decreases and then increases slowly. The rate of temperature rise in the cathode material increases with the temperature decreases. The volume of electrode material deformed with the expansion along the X-axis and the radial bending along the Y-axis. And the law of stress variation with time is consistent with the temperature-time curve. By the stress-strain distribution nephogram, it is found that the position where the maximum stress is located at the edge of the upper surface, and which is most vulnerable to failure. [ABSTRACT FROM AUTHOR]

The precipitation method is an efficient, economically feasible, and reproducible synthetic route to cathode materials for lithium-ion batteries with attractive performance characteristics, in particular, lithium iron phosphate (LiFePO4). This paper reviews the mechanisms of the key steps of the synthesis, namely, precipitation of iron phosphate FePO4 followed by its sintering with a lithium-containing raw material to give the LiFePO4 phase. The most probable interactions determining the kinetics of the precipitation process are considered using the data on the dissociation degree of the reacting components. The influence of the nature and concentrations of the commonly used sources of iron (FeSO4, FeCl3, Fe(NO3)3) and phosphorus (H3PO4, NH4H2PO4, (NH4)2HPO4), as well as the precipitation conditions (pH, temperature) on the precipitation efficiency of FePO4 is analyzed. The effect of the nature of the lithium-containing raw material (LiOH, Li2CO3, LiNO3) and the sintering (calcination) temperature on the morphology, phase composition, and electrochemical properties of the resulting LiFePO4 is discussed. The possibility is considered of obtaining spherical particles with high bulk density, which provides high specific and volumetric energy density of electrochemical cells. Based on the relationships established, optimal parameters for the synthesis of LiFePO4 with preliminary FePO4 precipitation step are proposed. [ABSTRACT FROM AUTHOR]

Given its safer working potential and higher theoretical capacity, Li3VO4 has become a potential alternative anode material to graphite. However, the hydrophilicity, low electrical conductivity, and unsatisfactory reaction kinetics of the Li3VO4 anode pose a challenge. In this paper, a graphene-wrapped Li3VO4@rGO hybrid was prepared using a novel efficient uniform rotation solvothermal (URS) method. Graphene with high electrical conductivity accelerates the reaction kinetics of the anode material to improve its rate performance. The URS method restrains the agglomeration of particles to shorten the diffusion paths of Li+. The uniform reaction obtained by this method and the lamellar shape of graphene synergistically enlarge the specific surface area of Li3VO4 to supply additional active sites for the extraction/insertion of Li+. Therefore, Li3VO4@rGO–R exhibits superior cycling performance (249.5 mA h g−1 after 4000 cycles at 5 A g−1) and rate performance (243.3 mA h g−1 at 10 A g−1). This study provides a versatile and efficient method for enhancing the electrochemical performance of anode materials. [ABSTRACT FROM AUTHOR]

This study introduces a novel label-free immunosensor that has the potential to be utilized for clinical screening and diagnosis of prostate cancer. The electrochemical immunosensor's performance was enhanced by combining 3,4-ethylenedioxythiophene (EDOT), 3-methylthiophene (3MT), and gold nanoparticles (AuNPs), enabling the accurate and sensitive determination of serum prostate specific antigen (PSA) concentrations. The immunosensor platform used [Fe(CN)6]3−/4− as a redox probe to obtain the signal, and the DPV technique was used to correlate the signal with the PSA concentration. The linear range of AuNPs/p(EDOT-co-3MT)/PGE is 0.1 to 50 000 pg mL−1, with a detection limit of 0.083 pg mL−1. In interference studies with interferences such as bovine serum albumin, carcinoembryonic antigen, uric acid, ascorbic acid, vitamin B12, vitamin B9, L -tyrozine, L -phenylalanine, Cu2+, Fe2+, and Zn2+ the immunosensor showed excellent anti-interference properties. The designed sensor platform is facile, inexpensive, highly sensitive, and selective, and has a high surface area, excellent electrical conductivity, and biocompatibility. Furthermore, this technology is highly suitable for industrial-scale production and can be easily converted into point-of-care detection devices due to its low cost, reproducibility, selectivity, and accuracy. [ABSTRACT FROM AUTHOR]

Nano metal–organic frameworks as an attractive new class of porous materials, are synthesized via metal ions and organic ligands. With their desirable properties of abundant pores, high specific surface areas, fully exposed active sites and controllable structures, nano MOFs are acknowledged to be one of the most vital materials in electrochemical energy storages. However, in their practical applications, nano MOFs are still confronted with various difficulties and challenges because of their low conductivity, poor stability, and other disadvantages. The selection and development of MOF composites, MOF–derived materials and modified MOFs might be beneficial to use as better electrode materials to greatly improve the electrochemical properties of energy storage devices. This paper mainly focuses on the recent developments of nano MOFs as prospective materials in electrochemical energy storage applications, including lithium–ion batteries (LIB), lithium–sulfur batteries (LSB), zinc–ion batteries (ZIB), and supercapacitors (SCs). Finally, the challenges faced by these kinds of energy storage devices are proposed, along with the current directions and prospect. [ABSTRACT FROM AUTHOR]

Tin disulfide (SnS2) is a highly promising anode material for sodium-ion batteries (SIBs) due to its substantial theoretical capacity stemming from alloying reactions and conversion mechanisms. Eliminating non-conductive binders and simplifying fabrication, the binder-free SnS2@carbon cloth (SnS2@CC) electrode is gaining attention. In this study, a one-step solvothermal synthesis was applied to fabricate binder-free SnS2@CC structures as SIB anodes. The electrochemical performance was enhanced by doping copper (Cu) into the SnS2 lattice. Solvothermal duration and Cu doping levels were systematically investigated to optimize the electrochemical properties of anodes. The Cu-doped SnS2@CC (Cu–SnS2@CC) electrodes exhibited superior electrical conductivity and sodium ion diffusion coefficients compared to those for the SnS2@CC electrodes. After 30 cycles, the Cu–SnS2@CC electrode prepared using a 15-h solvothermal process and 2% Cu doping achieved the highest capacity of 1092.8 mA h g−1 at 0.1 A g−1, while the SnS2@CC electrode yielded only 436.4 mA h g−1 under the same conditions. The optimized Cu–SnS2@CC electrode demonstrates excellent rate performance and cycling stability, with a capacity retention of 63% and Coulombic efficiency of 100% after 130 charge/discharge cycles. This research paves the way for high-performance, binder-free SnS2-based anodes in SIBs. [ABSTRACT FROM AUTHOR]

With the surging demand for green energy and renewable energy, as well as the shortage and uneven distribution of global lithium resources, sodium-ion batteries are gaining increasing attention as competitive alternatives. Due to their advantages of high energy density, high safety performance and environmental friendliness, P2 layered oxides have wide application prospects as the positive electrode of sodium ion batteries. However, their practical applications face numerous obstacles due to their complex phase transitions at high voltages, leading to poor cycling stability and rate capability. In this study, a P2-type Na0.67Ni0.2Mn0.8O2 layered oxide cathode material was successfully prepared via a two-step method using ultra-nano-sized precursors. Meanwhile, the sintering temperature was optimized for its influence on phase as well as the electrochemical properties of cathode material for sodium-ion batteries. The materials were characterized in terms of their morphology, structure, and electrochemical properties using SEM, XRD, EDX, and galvanostatic charge–discharge tests. Compared to the traditional one-step solid-state method, the PS-900 material obtained by a two-step approach exhibited a reversible capacity of over 150 mA h g−1 at 0.1 C and the capacity retention reached nearly 70% after 200 cycles at 1 C. These results indicate the widespread potential application of the novel P2-type layered oxide cathode material in sodium-ion batteries. [ABSTRACT FROM AUTHOR]

Exploring new strategies to design non-precious and efficient electrocatalysts can provide a solution for sluggish electrocatalytic kinetics and sustainable hydrogen energy. Transition metal selenides are potential contenders for bifunctional electrocatalysis owing to their unique layered structure, low band gap, and high intrinsic activities. However, insufficient access to active sites, lethargic water dissociation, and structural degradation of active materials during electrochemical reactions limit their activities, especially in alkaline media. In this article, we report a useful strategy to assemble vanadium diselenide (VSe2) into a 3D MXene/rGO-based sponge-like architecture (VSe2@G/MXe) using hydrothermal and freeze-drying approaches. The 3D hierarchical meso/macro-pore rich sponge-like morphology not only prevents aggregation of VSe2 nanosheets but also offers a kinetics-favorable framework and high robustness to the electrocatalyst. Synergistic coupling of VSe2 and a MXene/rGO matrix yields a heterostructure with a large specific surface area, high conductivity, and multi-dimensional anisotropic pore channels for uninterrupted mass transport and gas diffusion. Consequently, VSe2@G/MXe presented superior electrochemical activity for both the HER and OER compared to its counterparts (VSe2 and VSe2@G), in alkaline media. The overpotentials required to reach a cathodic and anodic current density of 10 mA cm−2 were 153 mV (Tafel slope = 84 mV dec−1) and 241 mV (Tafel slope = 87 mV dec−1), respectively. The Rct values at the open circuit voltage were as low as 9.1 Ω and 1.41 Ω for the HER and OER activity, respectively. Importantly, VSe2@G/MXe withstands a steady current output for a long 24 h operating time. Hence, this work presents a rational design for 3D microstructures with optimum characteristics for efficient bifunctional alkaline water-splitting. [ABSTRACT FROM AUTHOR]

The development of electrochemical sensors operating at low potentials is a promising method for monitoring environmental toxicants. In this research study, we designed and synthesized a redox active material, ferrocene conjugated biphenyl pyridine acrylonitrile (Fc-BPy), and applied it for the low potential non-enzymatic detection of catechol (CC) through electrochemical technique. Fc-BPy was systematically characterised using single-crystal XRD (SC-XRD). Fc-BPy crystallizes in a triclinic crystal system with a P-1 centrosymmetric space group. The electrochemical investigation of the Fc-BPy/GCE modified electrode exhibits a well-defined redox peak at a low anodic (Epa) and cathodic (Epc) peak potential of 0.32 V and 0.21 V, respectively, which favours the non-interference and selective detection of CC. Furthermore, commendable conductivity was achieved in the absence of any other conducting material due to a profound charge transfer between Fc-BPy and the electrode surface. In amperometry, Fc-BPy/GCE shows excellent non-enzymatic electrocatalytic activity towards CC over a linear detection range from 20 μM to 1.02 mM. The sensitivity and limit of detection (LOD) of CC were found to be 36.42 mM μA−1 cm−2 and 6.2 μM, respectively. Additionally, the fabricated sensor showed consistent performance over multiple cycles and extended periods of storage. The practical utility of the sensor for the detection of CC was tested in various real-time samples. The results were astounding with good recovery rates. Thus, the fabricated sensor exhibits a striking performance for the non-enzymatic detection of CC at a low potential with a high sensitivity, selectivity, better linear range, and low limit of detection. [ABSTRACT FROM AUTHOR]

Anode materials based on metal oxychlorides hold promise in addressing electrode dissolution challenges in aqueous‐based chloride ion batteries (CIBs). However, their structural instability following chloride ion deintercalation can lead to rapid degradation and capacity fading. This paper investigates a cobalt‐doped Sb4O5Cl2‐graphene (Co‐Sb4O5Cl2@GO) composite anode for aqueous‐based CIBs. It exhibits significantly enhanced discharge capacity of 82.3 mAh g−1 after 200 cycles at 0.3 A g−1; while, the undoped comparison is only 23.5 mAh g−1 in the same condition. It also demonstrated with a long‐term capacity retention of 72.8 % after 1000 cycles (65.5 mAh g−1) and a favorable rate performance of 25 mAh g−1 at a high current density of 2 A g−1. Undertaken comprehensive studies via in‐situ experiments and DFT calculations, the cobalt (Co) dopant is demonstrated as the crucial role to enhance the lifetime of Sb4O5Cl2‐based anodes. It is found that, the Co dopant improves electronic conductivity and the diffusion of chloride ions beside increases the structural stability of Sb4O5Cl2 crystal. Thus, this element doping strategy holds promise for advancing the field of Sb4O5Cl2‐based anodes for aqueous‐based CIBs, and insights gain from this study also offer valuable knowledge to develop high‐performance electrode materials for electrochemical deionization. [ABSTRACT FROM AUTHOR]