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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]

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]

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]

As one of the most common inorganic ions in daily food and ecological environment, nitrate (NO3−) is potentially harmful to both environment and humans. Therefore, the detection of nitrate concentration is quite important. Chemical sensors, as analytical measurement tools, usually demonstrate high selectivity, fast analysis speed, simple structure, convenient operation, and low cost and are considered to be a promising method for ion identification and detection. In this paper, a miniaturized electrochemical electrode is fabricated based on the microfabrication technology, and an electrochemical sensor for the detection of nitrate concentration in water is developed by combining the deposition technology of nanometal particles with electrochemical analysis technique. The developed electrochemical sensor utilizes electrochemical deposition to prepare a copper (Cu) granular sensitive film with a branch-cluster structure on the surface of a circular working electrode (Pt). Using copper's characteristics of electrocatalytic reduction of NO3− in the acid solution environment (pH = 2), the concentration of NO3− in the water sample was calculated by measuring the reduction current on the working electrode when the electrocatalytic reduction reaction of NO3− occurred on the surface of the copper-sensitive membrane. The sensitive film is characterized and detected both with the scanning electron microscope (SEM) and X-ray diffraction analysis (XRD) technique; and the microsensor is used to detect nitrate standard samples; a high detection sensitivity (24.9 μA/mmol·L−1) is achieved in the concentration range of 0.0 to 3.0 mmol/L. At the same time, a MEMS three-electrode sensor without gold wire bonding and insulating glue packaging is designed, and an automatic detection system is constructed with a STM32f103 microcontroller as the controller to realize the automated detecting process for nitrate ions. At the same time, a distributed system is constructed, which can describe the nitrate concentration in every position of the water area and realize the monitoring of the whole water area. The detection system can meet the working environment under most conditions and has practical significance. [ABSTRACT FROM AUTHOR]

Foamed metal materials are introduced as a novel tool to manufacture cathodes for the electrochemical machining (ECM) of involute internal spline made from difficult-to-cut materials. This paper analyzes the porosity density and electrolyte flow characteristics of foamed metal cathodes. The geometric and mathematical model of the involute internal spline by ECM is built, and electric field simulations are conducted by using the COMSOL Multiphysics software to determine the ECM results. Based on the simulation results, suitable initial process parameters are obtained and relative process experiments are carried out. The experiment results demonstrate that foamed metal material can be used to fabricate tool cathodes for ECM of involute internal spline. When the machining voltage is 10 V, the electrolyte type is 2% NaCl + 8% NaNO3 solution, and cathodic feed rate is 1.00 mm/min, the involute internal spline machined by axial ECM can achieve better profiles that meet the finishing accuracy and precision requirements. The experimental application of foamed metal cathode lays a new technical foundation for ECM to manufacture complex internal structures and from design theory to contemporary industrial praxis. [ABSTRACT FROM AUTHOR]

In this paper, [Ni0.9Co0.1](OH)2 precursor is used to dope H3BO3 to synthesize positive electrode material when mixing lithium in wet method, and to explore the best doping by testing the microscopic morphology and electrochemical performance of the positive electrode material amount and calcination temperature. After doping with B, the microstructure of the material is improved, and the primary crystal grains are oriented and agglomerated into a needle shape. This good crystal structure can slow down the generation of grain microcracks and mechanical fracture, and improve the cycle stability of the positive electrode material. After doping B, the discharge specific capacity was slightly improved. When the calcination temperature is 750 °C and the doping amount of B is 1.0 mol%, the first discharge specific capacity reaches 223 mAh g−1. More importantly, the capacity retention rate of the battery after 100 cycles has been greatly improved, from 74 % without doping B to 87 %. [ABSTRACT FROM AUTHOR]

As a class of promising cathodes in the field of large-scale power storage systems especially for alkali-metal-ion batteries (MIBs), Prussian blue (PB) and its analogues (PBAs) have received wide research attention due to their open framework, high theoretical specific capacity, and simple synthesis method. For large-scale applications, cathode materials with low-cost and long cycle life are preferred. However, only a few of the review papers have concentrated on the detailed analysis of low-cost PBAs, including Fe-based and Mn-based PBAs, which also show excellent electrochemical performance. This review aims to first provide an all-sided understanding of low-cost PBAs in terms of their application and recent progress in MIBs. Then, the major challenges such as inferior electrochemical properties of low-cost PBAs are discussed. Meanwhile, we provide feasible strategies to prepare PBA electrodes with advanced electrochemical performance. Finally, we present some personal perspectives and guidance for future research, aiming to narrow the gap between laboratory investigation and practical application. [ABSTRACT FROM AUTHOR]

With the application of electrochemical sensing technology in environmental detection, life science, biomedicine, food safety and other fields, the requirements for reference electrodes are also gradually increased. In this paper, the research and application progress of Ag/AgCl reference electrode are summarized from four aspects: 1) development situation of Ag/AgCl electrode; 2) preparation and application of Ag/AgCl electrode; 3) performance of charge transfer of Ag/AgCl electrode and influence of ion conduction on performance; 4) Research progress of doped modified Ag/AgCl electrode of carbon nanotubes. Ag/AgCl electrodes will remain the focus of future research due to their designability, flexibility, and excellent manufacturing properties. [ABSTRACT FROM AUTHOR]

Understanding the electrochemical and mechanical degradations inside the electrodes of lithium-ion battery is crucial for the design of robust electrodes. A typical lithium-ion battery electrode consists of active particles enclosed with conductive binder and an electrolyte. During the charging and discharging process, these adjacent materials create a mechanical confinement which suppresses the expansion and contraction of the particles and affects overall performance. The electrochemical and mechanical response mutually affect each other. The particle level expansion/contraction alters the electrochemical response at the electrode level. In return, the electrode level kinetics affect the stress at the particle level. In this paper, we developed a multiphysics–multiscale model to analyze the electrochemical and mechanical responses at both the particle and cell level. The 1D Li-ion battery model is fully coupled with 2D representative volume element (RVE) model, where the particles are covered in binder layers and bridged through the binder. The simulation results show that when the binder constraint is incorporated, the particles achieve a lower surface state of charge during charging. Further, the cell charging time increases by 7.4% and the discharge capacity reduces by 1.4% for 1 C-rate charge/discharge. In addition, mechanical interaction creates inhomogeneous stress inside the particle, which results in particle fracture and particle–binder debonding. The developed model will provide insights into the mechanisms of battery degradation for improving the performance of Li-ion batteries. [ABSTRACT FROM AUTHOR]

The development of society challenges the limit of lithium-ion batteries (LIBs) in terms of energy density and safety. Lithium-rich manganese oxide (LRMO) is regarded as one of the most promising cathode materials owing to its advantages of high voltage and specific capacity (more than 250 mA h g−1) as well as low cost. However, the problems of fast voltage/capacity fading, poor rate performance and the low initial Coulombic efficiency severely hinder its practical application. In this paper, we review the latest research advances of LRMO cathode materials, including crystal structure, electrochemical reaction mechanism, existing problems and modification strategies. In this review, we pay more attention to recent progress in modification methods, including surface modification, doping, morphology and structure design, binder and electrolyte additives, and integration strategies. It not only includes widely studied strategies such as composition and process optimization, coating, defect engineering, and surface treatment, but also introduces many relatively novel modification methods, such as novel coatings, grain boundary coating, gradient design, single crystal, ion exchange method, solid-state batteries and entropy stabilization strategy. Finally, we summarize the existing problems in the development of LRMO and put forward some perspectives on the further research. [ABSTRACT FROM AUTHOR]

In this work, β-FeOOH was synthesized and grown on carbon paper with the assistance of dopamine (PDA) via a facile hydrothermal method, producing β-FeOOH self-supporting electrode eventually. Electrochemical anodic oxidation performance to methyl orange (MO) solution using β-FeOOH anode was investigated and the major influencing factors such as current density, initial pH value and initial MO concentration on MO degradation efficiency were further explored. Experimental results suggested that 99.4% degradation rate of MO could be achieved only after 25 min electrolysis, its pseudo first-order reaction kinetic constant was 11.3 ⅹ 10−2 min−1 and the COD removal ratio was 37.3% after 120 min electrolysis under optimized conditions: current density was 10 mA cm−2, initial pH value was 3 and initial MO concentration was 10 mg L−1. At the same time, β-FeOOH electrode also exhibited a high cycling stability and the MO removal ratio was still keeping at 84.9% after eight cycles. Moreover, this electrode showed efficient decomposition performance to multiple simulated pollutants, indicating the well potential practical application values of β-FeOOH electrode. At last, the proposed degradation mechanism of MO was evaluated according to the analyzing results of UV–vis and HPLC-MS to MO solution under different degradation durations. • β-FeOOH self-supporting electrode was prepared via a facile hydrothermal method. • 99.4% removal ratio of MO could be achieved only after 25 min electrolysis. • Operating conditions during electrochemical degradation process were optimized. • The degradation intermediates of MO were identified and pathways were proposed. [ABSTRACT FROM AUTHOR]

In order to develop sustainable and renewable energy sources, novel approaches to design noble metal-free efficient electrocatalysts such as carbon and metal dichalcogenides nanostructures are being investigated for hydrogen evolution reaction (HER). In the present work, we successfully synthesize iron nanoparticles (Fe–GT) via facile green approach without using any surfactant and for the first time, green-synthesized iron nanoparticles are utilized as catalysts for production of multiwalled carbon nanotubes (MWCNTs). The synthesized MWCNTs (GT) were characterized using SEM, TEM, XRD and Raman spectroscopy techniques. The MWCNTs (GT)-coated conducting carbon paper electrode was applied as non-precious metal electrocatalyst for HER. The MWCNTs (GT) electrode demonstrates improved electrochemical activity towards HER with a smaller value of Tafel slope ~ 105 mV dec− 1 and overpotential (η10) ~ 192 mV, which is quite comparable to other reported metal-free HER catalyst. We also designed an indigenous electrochemical cell and showed the hydrogen production and collection using MWCNTs (GT) as cathode. [ABSTRACT FROM AUTHOR]

Bismuth has a great potential as the anode for sodium-ion batteries (SIBs) because of the layered structure with large interlayer space, long mean free path, and high volumetric capacity. In this paper, carbon-coated bismuth (Bi@C) core-shell nanostructure has been in situ synthesized by one-step direct current (DC) arc discharge method for the first time. The Bi@C nanocomposite without further decoration or any other treatment exhibits superior electrochemical performance as anode for SIBs and delivers stable capacities of 356, 342, 334, 327, 325, 323, and 318 mA h g − 1 at the current densities of 0.2, 0.5, 1, 3, 5, 7 and 10 A g − 1 , respectively. There is no obvious decay after 630 cycles with a capacity of 291 mA h g − 1 at 10 A g − 1 , showing the excellent rate capability and long cycle stability in SIBs. Electrochemical tests proved that the ultra-fast charge–discharge performance is related to the fast redox kinetics of Na + in layered structure of bismuth crystal. The Na + storage mechanism of Bi@C nanocomposite anode was also investigated by cyclic voltammetry and in situ XRD. Based on experimental data, this paper proves that the arc discharge method is a simple and efficient method for preparing nanoscale electrode materials. Bismuth has a great potential as the anode for sodium-ion batteries (SIBs). In this work, Bi@C core-shell nanostructure has been successfully prepared by one-step arc discharge method. Without further decoration, it can deliver a reversible capacity of 291 mA h g–1 beyond 630 cycles at the current density of 10 A g–1, which exhibits superior electrochemical performance as anode for SIBs. [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]

[Display omitted] • PO 4 3−-doping and Li 3 PO 4 -coating of dual modification of LiNiO 2 are achieved. • PO 4 3− doping improves the reversibility of crystal structure. • PO 4 3− doping induces surface structural transformation of the material. • Li 3 PO 4 coating could ameliorate the interface stability. Lithium nickel oxide (LiNiO 2) cathode materials are featured with high capacity and low cost for rechargeable lithium-ion batteries but suffer from severe structure and interface instability. Bulk doping together with surface coating has been proven to be an efficient approach to improve the inner structure and interfacial stability of the LiNiO 2 cathode material. Nevertheless, the role of anion doping seems to be quite different from that of cation doping, and a deep insight will be desirable for the structure design of the LiNiO 2 cathode material. In this paper, PO 4 3−-doped and Li 3 PO 4 -coating of dual modification of LiNiO 2 are achieved via a facile approach. It is demonstrated that the PO 4 3− anions are doped into the tetrahedron vacant sites of the crystal structure, alleviating the phase transition and improving the reversibility of crystal structure. Besides, the Li 3 PO 4 coating layer ameliorates the interface stability to restrain the side reactions. Therefore, the dual modification enhances overall structural stability of the material to provide excellent performance. Moreover, the consumption of the Li residues by the formation of Li 3 PO 4 coating layer, and the enlarged interlayer spacing of the crystal structure by PO 4 3− doping can facilitate the Li+ ions diffusion, resulting in a superior rate capability. [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]

Bis(diimino)metal complex nanosheets composed of metal ions and hexaaminobenzene ligands (MHABs) are fascinating two-dimensional materials which have been gaining significant attention as electrode materials and electrocatalysts owing to their electrical conductivities, redox properties, and porous structures obtained by the π-conjugated system and regular metal complex arrangement. Although electrochemical oxidation enables the simple and direct formation of MHABs on electrodes within a couple of minutes only, the obtained MHABs are relatively rough and of low crystallinity. This study investigated the effects of the applied potential during the synthesis, the type of base, and the concentrations of bases and building blocks on the synthesis of NiHAB nanosheets. Optical microscopy (OM), atomic force microscopy (AFM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and grazing-incidence X-ray scattering (GIXS) results revealed that a low oxidation potential, high concentration of the ammonia solution, and low concentration of the building blocks in the reaction solution provided a nanometre-thick NiHAB layer. Under the optimal reaction conditions, NiHAB nanosheets were successfully synthesized in a face-on orientation manner on gold electrodes using electrochemical oxidation methods. Furthermore, the anisotropic electrochemical synthesis of CuHAB was achieved under the optimised conditions. The mechanism of the MHAB growth process with an anisotropic orientation and nanometre thickness was proposed and attributed to the flat adsorption of p-conjugated oligomers composed of bis(diamino)metal moieties in a solution onto an electrode surface and the electrochemical oxidation and deprotonation of the adsorbates on the electrode. [ABSTRACT FROM AUTHOR]

Developing non-precious, stable, and highly efficient electrocatalyst materials is crucial for large-scale practical HER applications. Ni3S2 is a prominent catalyst due to its high efficiency and ease of preparation. Nevertheless, its usability is restricted by poor Ni site water molecule adsorption and strong hydrogen bonding between sulphur and hydrogen. The concentration of precursors and samples' morphology significantly affect the electrochemical performance of electrodes intended for the hydrogen evolution reaction (HER) application. This study examines how Mo transition metal sulfide concentration influences the Mo–Co–Ni3S2/NF catalyst's structural aspects and its subsequent electrochemical performance. In situ hydrothermal processing is used to prepare the samples through a two-step process. The samples exhibit enhanced electrocatalytic properties. Specifically, comparatively low overpotentials of 215 mV and 332 mV were observed at current densities of 10 mA cm−2 and 50 mA cm−2, respectively. Additionally, a Tafel slope of 104 mV dec−1 was recorded at a 75 : 25 ratio of molybdenum to cobalt concentration. The samples also demonstrate excellent stability. [ABSTRACT FROM AUTHOR]

Silicon-based materials have become one of the most likely materials to replace graphite anodes of Li-ion batteries due to their ultra-high theoretical specific capacity, safe lithium intercalation potential, and abundant reserves. However, the large volume effect of silicon-based materials during cycling has become a serious obstacle to their commercial application. Silicon-metal composite is one of the potential solutions to alleviate the volume effect of silicon-based anode. Traditional electrodes are prepared by slurry coating method, and the electrodes crack and fall off after many cycles, resulting in capacity loss. In this paper, a cold spraying method combined with ball milling was proposed to prepare silicon-copper composite electrodes to improve the bonding between electrode materials and the cycling stability of the electrodes. Composite powders with different component ratios were first prepared. Then, the micromorphology, bond strength, thermal conductivity, and electrochemical performance of the electrodes prepared by the slurry coating method and the cold spray method were analyzed, respectively. The results show that the Cu100-xSix cold sprayed electrodes have higher bond strength and porosity, while the higher porosity of the cold-sprayed electrodes does not promote heat transfer. After the addition of conductive carbon black, the electrodes exhibit better structural stability, cycling performance, capacity retention, and reaction kinetics, with the Cu80Si20 + SP cold prayed electrode exhibiting 600 mAh g−1 after 200 cycles. This work not only successfully prepared a silicon-copper composite anode with excellent performance but also provided a reference for the preparation of other composite electrodes by cold spray combined with ball milling. [ABSTRACT FROM AUTHOR]

The manufacturing of surface microstructure is an important means for the modification of surface characteristics of parts. Through-mask electrochemical manufacturing is also an efficient way to fabricate surface microstructures. Nevertheless, in cases where the through-mask electrochemical manufacturing is used for the fabrication of microstructures, many experiments are required to control the cross-section morphology of the microstructures. Furthermore, there is a lack of quantitative analysis of the impact of key variables on the process. In this paper, using numerical simulations based on the mask geometry, we analyze the effects of the aspect ratio of mask feature and the gap between cathode to mask on electrochemical micromachining. We further investigate the influence laws of the mask geometry on the anode current density distribution and forming process. A critical value of "0.8" is also determined for aspect ratio of mask feature which is closely related to the anode current density distribution and forming process. The through-mask electrochemical micromachining experiments confirm the effect laws of the geometric structure of the mask feature. And the critical value (0.8) of aspect ratio can be used as the basis for selecting mask feature. [ABSTRACT FROM AUTHOR]

Conventional glassy carbon electrodes (GCE) cannot meet the requirements of future electrodes for wider use due to low conductivity, high cost, non-portability, and lack of flexibility. Therefore, cost-effective and wearable electrode enabling rapid and versatile molecule detection is becoming important, especially with the ever-increasing demand for health monitoring and point-of-care diagnosis. Graphene is considered as an ideal electrode due to its excellent physicochemical properties. Here, we prepare graphene film with ultra-high conductivity and customize the 3-electrode system via a facile and highly controllable laser engraving approach. Benefiting from the ultra-high conductivity (5.65 × 105 Sm−1), the 3-electrode system can be used as multifunctional electrode for direct detection of dopamine (DA) and enzyme-based detection of glucose without further metal deposition. The dynamic ranges from 1–200 µM to 0.5–8.0 mM were observed for DA and glucose, respectively, with a limit of detection (LOD) of 0.6 µM and 0.41 mM. Overall, the excellent target detection capability caused by the ultra-high conductivity and ease modification of graphene films, together with their superb mechanical properties and ease of mass-produced, provides clear potential not only for replacing GCE for various electrochemical studies but also for the development of portable and highperformance electrochemical wearable medical devices. [ABSTRACT FROM AUTHOR]

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LiNi0.8Co0.1Mn0.1O2 (NCM811), a high nickel-positive electrode material, has higher discharge capacity, lower cost, and less environmental pollution than other systems, so it has attracted many people's attention. However, its poor thermal stability, cycle rate performance, and safety problems limit its practical application. In this paper, the NCM811 cathode material with Al3+ and PO43− co-doping (NCM-PA) was prepared by co-precipitation method and high-temperature solid-state method to improve its properties. The results show that the co-doping can effectively inhibit the mixing of lithium and nickel, maintain the good lamellar structure of the cathode material, and improve the electrochemical performance of the cathode material. The capacity retention rate of NCM-PA is 14.1% higher than that of the raw material after 100 cycles at 1 C. In addition, due to the small degree of electrode polarization of the co-doping material, NCM-PA still has a discharge-specific capacity of 155.8 mAh/g when the current density is 5 C. [ABSTRACT FROM AUTHOR]

Conventional refractory materials used for calcining ternary lithium‐ion battery cathode materials, such as mullite, cordierite, and magnesia‐alumina spinel, are vulnerable to attack by Li(NixCoyMn1−x−y)O2 (LNCM) materials and therefore have a short service life. In order to improve the corrosion resistance of refractory materials to LNCM materials, mullite‐Al2TiO5 materials with different contents were synthesized in this paper by using calcined mullite powder, TiO2 powder, and La2O3 powder as raw materials, which were calcined at 1500–1600°C temperature, respectively. In this study, the potential of the materials for the preparation of LNCM materials was investigated in terms of its physical properties, resistance to the corrosion of LNCM materials, and resistance to thermal shock. The results showed that mullite‐Al2TiO5 composites can be successfully synthesized at 1500–1600°C, and the physical properties of the materials met the production requirements. The prepared mullite‐Al2TiO5 composites also exhibited better physical properties, good corrosion resistance, and proper thermal shock resistance compared with mullite refractories. [ABSTRACT FROM AUTHOR]

This paper focuses on the evaluation of the mobility of four hexachlorocyclohexane (HCH) isomers by soil vapor extraction (SVE) coupled with direct electrokinetic (EK) treatment without adding flushing fluids. SVE was found to be very efficient and remove nearly 70 % of the four HCH in the 15‐days of the tests. The application of electrokinetics produced the transport of HCH to the cathode by different electrochemical processes, which were satisfactorily modelled with a 1‐D transport equation. The increase in the electric field led to an increase in the transport of pollutants, although 15 days was found to be a very short time for an efficient transportation of the pollutants to the nearness of the cathode. Loss of water content in the vicinity of the cathode warns about the necessity of using electrokinetic flushing technologies instead of simple direct electrokinetics. Thus, results point out that direct electrokinetic treatment without adding flushing fluids produced low current intensities and ohmic heating that contributes negatively to the performance of the SVE process. No relevant differences were found among the removal of the four isomers, neither in SVE nor in EK processes. [ABSTRACT FROM AUTHOR]

As a popular direction of research in micro-energy storage devices, improving the comprehensive performance of all-solid-state planar on-chip micro-supercapacitors (MSCs) has received increasing attention. Graphene quantum dots (GQDs) are a new type of nano-scale electrode materials that can improve the electrochemical performance of devices. In addition, the doping of nitrogen/oxygen heteroatoms can further improve the electrochemical activity of the electrode materials. In this paper, nitrogen-oxygen co-doped graphene quantum dots (NO-GQDs) were used as electrode materials, and a modified liquid-air interface self-assembly method was used to fabricate the electrode films. Finally, the MSCs with narrow interdigital electrode configuration were prepared by photolithography with an electrode width/interdigital gap of 3 μm/1 μm. The prepared MSCs have excellent electrochemical performance, including an area capacitance of 150.63 μF cm−2, an energy density of 20.92 nWh cm−2, a power density of 175.49 μW cm−2, a relaxation time constant of 3.53 μs, and a capacitance retention of 90.42%. As shown by the results, the combination of NO-GQDs and narrow interdigital electrode configuration provides a significant improvement in the comprehensive electrochemical performance of the all-solid-state planar on-chip MSCs. [ABSTRACT FROM AUTHOR]

Since there exist discharge problems in gas insulated metal-enclosed switchgear due to internal metal particle movement, the study in this paper thus, conducted an experiment and simulation research on the movement characteristics of particles, where the charge on particle and the collision recovery coefficient (CRC) was obtained. When the electrode is brass, the charge on the particle is close to the theory one and the CRC of aluminum, stainless steel and particle are 0.52, 0.75 and 0.79 respectively. Accordingly, the study, in order to take the particle charge and its collision process into consideration, established a particle movement model, and conducted a test has thereof. The results show that there exists excellent consistency between charge and its collision. According to the research, the relationship between particle size, material and collision characteristics was revealed. The result shows that under DC voltage the metal particle collision frequency decreases with the increase of particle size when the material of the particles is the same. The time difference between particles' moving to high voltage electrode and ground electrode becomes greater with the increase of the size of the particle. When the particle material is different, the collision characteristics are influenced by its density and collision recovery coefficient of restitution. Particle motion velocity loss becomes less before and after the collision when its collision recovery coefficient of restitution is larger. So the collision frequency is higher. The research results in this paper can offer some reference value to particles suppression measures in gas insulated metal-enclosed transmission line. [ABSTRACT FROM PUBLISHER]

Ammonia production via the electrochemical N 2 reduction reaction (NRR) at ambient conditions is highly desired as an alternative to the Haber-Bosch process, but remains a great challenge due to the low efficiency and selectivity caused by the competing hydrogen evolution reaction (HER). Herein we investigate the effect of availabilities of reactants (protons, electrons and N 2) on NRR using a FeO x -coated carbon fiber paper cathode in various electrochemical configurations. NRR is found viable only under the conditions of low proton- and high N 2 availabilities, which are achieved using 0.12 vol% water in LiClO 4 -ethyl acetate electrolyte and gaseous N 2 supplied to the membrane-electrode assembly cathode. This results in an NRR rate of 29 ± 19 pmol NH3 s−1 cm−2 at a Faradaic efficiency of 70 ± 24% at the applied potential of −0.1 V vs. NHE. Other conditions (high proton-, or low N 2 -availability, or both) yield a lower or negligible amount of ammonia due to the competing HER. Our work shows that promoting NRR by suppressing the HER requires optimization of the operational variables, which serves as a complementary strategy to the development of NRR catalysts. • Electrochemical N 2 reduction reaction (NRR) is viable at ambient conditions. • Electrochemical system with membrane-electrode assembly yields best NRR activity. • NRR is promoted at the condition of low proton- and high-N 2 availabilities. • High proton-, or low-N 2 availabilities or both favor H 2 evolution side reaction. [ABSTRACT FROM AUTHOR]

Ag catalysts show high selectivities in the conversion of carbon dioxide to carbon monoxide during the electrochemical carbon dioxide reduction reaction (CO2RR). Indeed, highly catalytically active porous electrodes with increased surface area achieve faradaic conversion efficiencies close to 100%. To establish reliable structure-property relationships, the results of qualitative structural analysis need to be complemented by a more quantitative approach to assess the overall picture. In this paper, we present a combination of suitable methods to characterize foam electrodes, which were synthesised by the Dynamic Hydrogen Bubble Templation (DHBT) approach to be used for the CO2RR. Physicochemical and microscopic techniques in conjunction with electrochemical analyses provide insight into the structure of the carefully tailored electrodes. By elucidating the morphology, we were able to link the electrochemical deposition at higher current densities to a more homogenous and dense structure and hence, achieve a better performance in the conversion of CO2 to valuable products. Metal foam electrodes are promising for efficient CO2 reduction, but detailed characterizations of the foams at the macro and nanoscale are lacking. Here, the authors combine physicochemical and microscopic techniques in conjunction with electrochemical analyses to relate the morphologies of silver foam electrodes to their CO2 reduction performance. [ABSTRACT FROM AUTHOR]

In order to alleviate the hydrogen evolution corrosion, passivation, and zinc dendrite growth during the charging and discharging of the zinc–bismuth negative electrode of zinc–air battery, the effects of the addition amounts of single Na2SiO3 and SDBS and their compounding on the corrosion inhibition effect and the charging and discharging performance of zinc–air battery in a new KOH-KF-K2CO3 electrolyte system were systematically investigated in this paper. In addition, the inhibition mechanisms of related inhibitors were discussed using FT-IR and XPS analyses. The results show that the addition of single Na2SiO3 and SDBS in the electrolyte can inhibit hydrogen evolution, dendrite formation, and passivation of the zinc electrode, thereby improving the charging/discharging performance of the battery, and the combination of Na2SiO3 and SDBS has a synergistic effect in improving corrosion inhibition and electrochemical performance of the electrode. When the additive concentration of the composite electrolyte is 1-g/L Na2SiO3 + 55-mg/L SDBS, the hydrogen evolution corrosion inhibition efficiency can reach 52.46%. Under the current density of 25 mA/cm2, the initial specific capacity and the capacity retention rate after the 300th cycle of the electrode can reach 523.5 mAh/g and 88.27%, respectively. It is found that both inhibitors can adsorb on the surface of zinc electrode in alkaline electrolyte to form a protective film on zinc electrode. The hydrogen evolution and corrosion inhibition effects of Na2SiO3 are better than SDBS, while the dendrite inhibition effect of SDBS is better than Na2SiO3. However, due to their different adsorption mechanisms, the compound addition can synergistically improve the coverage of the protective film, thereby inhibiting the corrosion, passivation, and dendrite of zinc electrode and effectively improve the first discharge specific capacity and cycle life of the battery. [ABSTRACT FROM AUTHOR]

Manganese-based materials are considered as potential cathode materials for aqueous zinc-ion batteries due to the advantages of high voltage platform, non-toxic, and environmental protection. However, the rapid decline capacity due to the dissolution of manganese and the low conductivity restrict its further development. In this paper, Ni2+-doped ZnMn2O4 nanoparticles were prepared and used as cathode materials for aqueous zinc-ion batteries. The Ni2+-doping effectively improves its electrochemical performance. The Ni2+-doped ZnMn2O4 cathode shows a discharge-specific capacity of 175 mAh g−1 after an activation process at current density of 100 mA g−1. At a high current density of 1A g−1, the cathode displays a specific capacity of 120 mAh g−1, and the Coulombic efficiency of above 97% can be maintained throughout the cycles except for the first cycle, indicating a high reversibility of charging/discharging. The Ni2+-doping increases the conductivity and zinc-ion diffusion coefficient of the material electrode through destroying the periodic potential field generated by the material. It shows that the synergistic effect of manganese and transition metal ions provides a possible direction for the future development of cathode materials for aqueous zinc-ion batteries. [ABSTRACT FROM AUTHOR]

The electrode configuration is an important element in the development of Li-ion cells. The energy density is proportional to the loading of the active material. Therefore, increasing the electrode thickness is the simplest way to achieve higher capacities. In this paper, we compare the effects of three different thicknesses of Ag-decorated Si electrode anode (HCSi) on the electrochemical performances such as the SEI layer formation, impedances, and mass capacitances. We prepared three different silicon electrode thicknesses to optimize the electrodes: 20, 40 and 60 µm and measured in situ galvanostatic electrochemical impedance spectroscopy (GEIS). Using GEIS, we studied the intercalation mechanism of Li+ ions in detail and found that despite having the same capacities (≈3500 mAh g−1), the thinnest electrode, HCSi20, allows diffusion of Li+ ions into the bulk, whereas thicker layers prevent smooth diffusion into the bulk of the silicon electrode due to increased layer resistance. The Voigt model was used to analyze the anomaly of the frequency dependence of the measured impedance, in which, the classical Randles circuit is connected in series with one or two R ‖ C parallel combinations. One R ‖ C circuit could be the result of the SEI formation, and the second R ‖ C circuit could be the contribution of Li. To increase the number of charge and discharge cycles, we improved the electrolyte by adding fluoroethylene carbonate (FEC), which reduced the capacity of the HCSi20 electrode to 50% of the initial capacity (≈3500 mAh g−1) after 60 cycles, whereas it dropped to 20% of the initial capacity after 10 cycles without the addition of FEC. [ABSTRACT FROM AUTHOR]

Facing the challenges of energy crisis and global warming, the development of renewable energy has received more and more attention. To offset the discontinuity of renewable energy, such as wind and solar energy, it is urgent to search for an excellent performance energy storage system to match them. Metal–air batteries (typical representative: Li–air battery and Zn–air battery) have broad prospects in the field of energy storage due to their high specific capacity and environmental friendliness. The drawbacks preventing the massive application of metal–air batteries are the poor reaction kinetics and high overpotential during the charging–discharging process, which can be alleviated by the application of an electrochemical catalyst and porous cathode. Biomass, also, as a renewable resource, plays a critical role in the preparation of carbon-based catalysts and porous cathode with excellent performance for metal–air batteries due to the inherent rich heteroatom and pore structure of biomass. In this paper, we have reviewed the latest progress in the creative preparation of porous cathode for the Li–air battery and Zn–air battery from biomass and summarized the effects of various biomass sources precursors on the composition, morphology and structure-activity relationship of cathode. This review will help us understand the relevant applications of biomass carbon in the field of metal–air batteries. [ABSTRACT FROM AUTHOR]

In this paper, a simple strategy was proposed for the analysis of catechol by a carbon paste electrode (CPE) modified with graphene oxide–third generation of poly(amidoamine) dendrimer (GO/G3–PAMAM) nanocomposite and ionic liquid (IL). The synthesis of GO–PAMAM nanocomposite was confirmed using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FE-SEM), and Fourier transform infrared spectroscopy (FT-IR) techniques. The prepared modified electrode (GO–PAMAM/ILCPE) exhibited good performance to detect catechol with a notable decrease in overpotential and increase in current compared with an unmodified CPE. Under optimum experimental conditions, GO–PAMAM/ILCPE electrochemical sensors indicated a lower limit of detection (LOD) of 0.034 μM and a linear response in the concentration range of 0.1 to 200.0 µM for the quantitative measurement of catechol in aqueous solutions. In addition, GO–PAMAM/ILCPE sensor exhibited an ability to simultaneously determine catechol and resorcinol. It can be found that catechol and resorcinol could be completely separated on the GO–PAMAM/ILCPE with the differential pulse voltammetry (DPV) technique. Finally, a GO–PAMAM/ILCPE sensor was utilized to detect catechol and resorcinol in water samples with recoveries of 96.2% to 103.3% and relative standard deviations (RSDs) of less than 1.7%. [ABSTRACT FROM AUTHOR]

In order to reduce by-product nitrite, a more toxic compound than nitrate, and increase high value-added products ammonia in the electrochemical reduction nitrate process, the novel Cu–Co/Ti cathode material was applied in this process. In this paper, the electrochemical process was carried out in a single compartment electrolytic cell, and with Cu–Co/Ti electrode as cathode, identifying the effects of current density, pH, electrolytes in the nitrate reduction, and the distribution of products. The Cu–Co/Ti cathode exhibited 94.65% NO3−-N (nitrate–N) removal, 0.18% NO2−-N (nitrite-N) generation, and 40.86% NH4−-N (ammonia-N) generation with the assistance of Na2SO4 electrolyte in 6 h at 10 mA cm−2 and pH 6. Compared with the Cu/Ti cathode, the higher nitrate removal ratio and lower nitrite generation ratio were obtained on the Cu–Co/Ti cathode. The excellent performance of Cu–Co/Ti cathode is ascribed to the synergy of Cu and Co, which couples the facilitation of nitrate conversion to nitrite and the acceleration of nitrite reduction on the Cu–Co/Ti cathode. The LSV curves showed that nitrate and nitrite might undergo indirect and direct reduction reactions on Cu–Co/Ti cathode. The possible pathways of nitrate reduction on the Cu–Co/Ti cathodes were proposed. These results highlight the viability of using the Cu–Co/Ti cathode developed at this work for the nitrate removal from contaminated waters. This study achieved low-nitrite generation by Cu–Co/Ti cathode during electrochemical nitrate reduction. [ABSTRACT FROM AUTHOR]

By using Ni‐rich material (LiNixCoyMnzO2, x+y+z=1) as cathode electrode, the energy density of lithium‐ion batteries can be increased. However, the electrode/electrolyte interface instability of Ni‐rich cathode at high voltage will adversely affect the cycle performance and limit its practical application. In this paper, propanediol cyclic sulfate (PCS) is proposed as a functional additive to improve the cycling stability of LiNi0.6Co0.1Mn0.3O2/graphite battery. After adding 3.0 wt.% PCS to the baseline electrolyte, the capacity retention of the batteries improves from 9.6 % to 86.5 % after 150 cycles at the voltages of 3.0–4.5 V. Based on the theoretical calculation and experimental result, the main reason for the improvement of electrochemical performance is that the PCS forms a highly stable sulfur‐containing compound interface layer (SEI/CEI) on the electrode surface, which can not only inhibit electrolyte decomposition and interface impedance increase, but also reduce transition metal dissolution. This work has given some ideas for the practical utilization of high‐voltage LiNi0.6Co0.1Mn0.3O2/graphite pouch‐cells. [ABSTRACT FROM AUTHOR]

BACKGROUND: To understand the effect of electron shuttle compounds on the electron transfer behavior of MFC and the formation process of microbially fabricated nanowires. In this paper, 2,6‐anthraquinone desulfonation (AQDS) and Fe(OH)3 were used as electron mediator and electron acceptor, respectively, to study the effect of electron mediator on the formation of bio‐nanowires during the growth of Geobacter metallireducens in the double chamber MFC reactor (MFC), and the effects of electron transfer efficiency and electrical current characteristic. RESULTS: The results show that the culture process of the Geobacter metallireducens with Fe(OH)3 as an electron acceptor, the reduction product Fe(II) concentration in solution without AQDS was higher than that with AQDS after 10 days due to the formation of microbial nanowires. In comparison, the Pili protein content of the system without AQDS reached 336 ug/mL, which was higher than the AQDS system. Nanowires increased the transfer efficiency between biofilm and electrodes, which increased the maximum output voltage of MFC was 442 mV. CONCLUSION: At the same time, it was found by electrochemical measurements that the nanowire biofilm electrode had a huge peak of the cyclic voltammetry curve, a small activation resistance, and a strong current response signal, indicating that the nanowires enhanced the electrochemical activity of the electrode. In addition, an electron transfer medium (AQDS) inhibited the expression of aromatic amino acids, tryptophan, and mtrC. Moreover, it destroyed the overlapping π‐π orbits of the aromatic parts, resulting in reduced and thinner nanowires and then decreasing the conductivity of synthetic organic materials like metals. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

NASICON‐type sodium vanadium phosphate (Na3V2(PO4)3, or NVP) cathode materials have great potential for fast charging and long cycling sodium‐ion batteries (SIBs) similar to lithium iron phosphate (LiFePO4, or LFP) cathode materials used in lithium‐ion batteries (LIBs). However, the cycle life and energy density in the full cell using NVP materials need to be significantly improved. This paper investigates the degradation mechanisms of NVP‐based SIBs and identifies the Na loss from the cathode to the anode solid electrolyte interphase (SEI) reactions as the main cause of capacity degradation. A new Na‐rich NVP cathode (e.g., Na4V2(PO4)3, or Na4VP) is developed to address the Na loss problem. Conventional NVP can be easily transformed into the Na4VP by a facile and fast chemical solution treatment (30 s). Na‐free‐anode Na4VP and hard carbon‐Na4VP full cells are assembled to evaluate the electrochemical properties of the Na‐rich NVP cathode. The Na4VP cathode provides excess Na to compensate for the Na loss, resulting much longer cycle life in the full cells (>400 cycles) and a high specific energy and power density. Good low‐temperature performance is also observed. [ABSTRACT FROM AUTHOR]

Lithium vanadium oxide (Li3VO4, LVO) is a promising anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity (394 mAh g−1) and safe working potential (0.5–1.0 V vs. Li+/Li). However, its electrical conductivity is low which leads to poor electrochemical performance. Graphene (GN) shows excellent electrical conductivity and high specific surface area, holding great promise in improving the electrochemical performance of electrode materials for LIBs. In this paper, LVO was prepared by different methods. SEM results showed the obtained LVO by sol-gel method possesses uniform nanoparticle morphology. Next, LVO/GN composite was synthesized by sol-gel method. The flexible GN could improve the distribution of LVO, forming a high conductive network. Thus, the LVO/GN composite showed outstanding cycling performance and rate performance. The LVO/GN composite can provide a high initial capacity of 350.2 mAh g−1 at 0.5 C. After 200 cycles, the capacity of LVO/GN composite remains 86.8%. When the current density increased from 0.2 C to 2 C, the capacity of LVO/GN composite only reduced from 360.4 mAh g−1 to 250.4 mAh g−1, demonstrating an excellent performance rate. [ABSTRACT FROM AUTHOR]

As a soluble dietary fiber, pectin has the functions of lowering cholesterol, reducing weight and improving human immunity. However, nowadays, many studies have been reported on the extraction of pectin, but few on its quantitative analysis. In this paper, graphene modified copper foam and copper sheet were used as working electrodes, respectively. Pt electrode as counter electrode and Ag/AgCl (saturated KCl solution) electrode was used as reference electrode to build electrochemical detection system. The electrochemical responses to pectinose solution were measured by voltammetry (CV) and chronoamperometry (i-t). The detection data were analyzed to develop pectinose quantitative analysis model. Results indicated that the proposed method could determine pectinose concentration in solution, and graphene modified copper foam presented better responses. The sensitivity was 0.68851A cm−2 mmol/L, the detection limit was 0.24825 mol/L. This method presents some advantages including fast response, easy operation, and low cost. It provides a new method for pectinose quantitative detection. [ABSTRACT FROM AUTHOR]

Capacity attenuation caused by Ni dissolution and interface instability during cycling is a major challenge because it limits the application of high Ni ternary cathode materials in Li‐ion batteries. In this paper, ternary LiNi0.85Co0.10Mn0.05O2 cathode with high nickel content was prepared by co‐precipitation method, and then was coated with perovskite La4NiLiO8 via the simple thermochemical method. The analysis of the images of transmission electron microscope (TEM) showed that the coating is uniformly covered on the surface of NCM85 material with a thickness of 5 nm. Compared to uncoated sample, the La4NiLiO8‐coated LiNi0.85Co0.10Mn0.05O2 material shows lower electrochemical impedance and better cyclic stability, the initial kinetic diffusion coefficient and the interface stability of the prepared material are greatly improved. Meanwhile, the problems of Li+/Ni2+ mixing are also been solved. This work provides a new strategy for improving the interface and thermal stability of the nickel cathode material of Li‐ion battery in the future. [ABSTRACT FROM AUTHOR]

Doping engineering is an effective modification strategy to enhance the electrochemical performance of electrode materials. In this paper, the impacts of heteroatom doping in monolayer titanium disulfide (TiS2) by substituting the S atom with the heteroatoms (B, C, N, O, F, and P) on the adsorption and diffusion capabilities of alkali metals (Li, Na, and K) have been systematically investigated using first-principles calculations to evaluate the material performance for application in alkali metal-ion batteries. The doping of most heteroatoms can promote the adsorption capability of alkali metal atoms on monolayer TiS2 as their adsorption energies decrease compared with the pristine system, particularly for p-type doping with C, N, and P. The diffusion energy barriers decrease when alkali metals approach the doping site of most heteroatom-doped TiS2, and the barriers near the doping site are extremely small (0.00–0.08 eV), whereas they slightly increase as alkali metals move away from the doping site. P doping has the lowest overall diffusion energy barrier for each metal. Thus, monolayer TiS2 with heteroatom doping, especially P doping, can be used as a potential anode material for alkali metal-ion batteries. This study can help comprehend the impacts of heteroatom doping and design high-performance electrode materials for rechargeable batteries. [ABSTRACT FROM AUTHOR]