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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]

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]

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]

Free standing electrodes have grabbed attention among the researchers around the globe due to its ease of fabrication, scale‐up and flexibility for stack development. In the present communication, we have described a novel approach to improve the areal capacitance of graphite fiber paper (GP) from 4.5 ×10−3 F cm−2 to 0.677 F cm−2 by surface modification. Surface functionalised graphite paper (Oxd‐GP) and its chemically reduced counterpart (Red‐GP) are explored as electrode materials for supercapacitors. The materials synthesized are structurally characterized by X‐ray diffraction (XRD), Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), Energy dispersive analysis of X‐rays (EDAX) and field emission scanning electron microscopy (FESEM). The electrochemical performance of the electrodes is assessed using cyclic voltammetry (CV), galvanostatic charge‐discharge (GC) analysis and electrochemical impedance spectroscopy (EIS) where both Oxd‐GP and Red‐GP exhibit appreciable areal capacitance while Red‐GP shows excellent cycle life over 2600 cycles. Red‐GP showed an increment in capacitance over 1000 cycles while attaining stability. This work suggests that modified graphite paper can be a low‐cost and free‐standing electrode for high performance energy storage devices. [ABSTRACT FROM AUTHOR]

Abstract: Modification of cellulosic paper with carbon nanotubes (CNT) was studied for the development of electronic and analytical devices. Interesting results were published by using a CNT aqueous solution and the capillary forces of filter paper to make conductive tracks, supercapacitors, potentiometric electrodes and chemometric sensors. In this report, we show for the first time an electrochemical characterization of CNT‐CS‐SDS paper electrodes constructed with an ink containing optimized proportions of multi‐wall CNT, chitosan (CS) and sodium dodecyl sulfate (SDS), and we compared our data with CNT‐SDS paper electrodes constructed with a previously reported ink. We achieved better reversibility (ΔE=131±14 mV, CVs) and reproducibility (RSD=3.63 %) with CNT‐CS‐SDS paper electrodes, when compared to CNT‐SDS paper electrodes (ΔE=249±7 mV; RSD=6.8 %) used as controls. When electrodes were fold at 90° angle, CNT‐CS‐SDS paper electrodes showed lower RSD than CNT‐SDS paper electrodes, 8.43 % and 21.5 % respectively. These results are in concordance with SEM analysis indicating a dense CS film in CNT‐CS‐SDS paper electrodes. As a proof of concept, we determine dopamine concentration by DPV in the presence of ascorbic and uric acids, the limit of detection calculated was 6.32 μM. Moreover, a bismuth‐film was prepared by in situ plating of Bi into CNT‐CS‐SDS paper electrodes. ASV allowed us to detect Pb in the presence of Bi (10–200 ppb) with a limit of detection of 6.74 ppb. [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]

Abstract: Paper‐based analytical devices, which are suited to point‐of‐care diagnostics and on‐site detection because of cheap price and portability, have attracted increasing attention for improving global health and in other applications. Here, we constructed one carbon nanotube paper‐based electrode (CNTPE) for the detection of neurochemicals in brain microdialysate. CNTPE was directly fabricated through filter depositing CNT dispersion onto the surface of filter paper. The fabricated CNTPE have good electrochemical performance with advantage of CNT, which not only facilitate ascorbic acid (AA) oxidation, also could as a good platform to functionalize. As a proof, we demonstrate that the CNTPE act as electrode to detect AA directly and detect glucose with further modified CNTPE through electrodeposited Prussian blue (PB). The results show that the easily prepared CNTPE can be used for the selective measurement of AA without interference from dopamine and other electrochemical active substances; what's more, PB and glucose oxidase (GOx) modified CNTPE has good performance towards the specific detection of glucose. Therefore, we believe that CNTPE would have great potential application in detection of chemicals to understand the function of brain. [ABSTRACT FROM AUTHOR]

This paper demonstrates, for the first time, the use of paper-based electrochemical devices coupled to external solid working electrodes. The paper-based electrochemical cells were fabricated using inexpensive and largely available office paper, according to a simple protocol that consists on the creation of hydrophobic barriers using paraffinized paper and preheated metal stamp. The counter and reference electrodes were integrated to the paper platform through the deposition of carbon and silver inks, respectively. The electrochemical paper analytical device (ePAD) was coupled to external glassy carbon rod electrode modified with reduced graphene oxide doped with Cu nanoparticles through meniscus configuration. The analytical usefulness of this electrochemical approach was demonstrated through the simultaneous determination of paracetamol and caffeine in biological samples. The analytes were successfully quantified in real urine samples and limits of detection of 24.6 nM (paracetamol) and 36.1 nM (caffeine) were obtained. The paper platform showed good stability (RSD of 1.07 % for the peak currents and 1.43 % for the peak potentials) and satisfactory performance. The use of solid electrodes coupled to paper electrochemical devices, firstly demonstrated here, opens new possibilities for the utilization of ePADs in electrochemistry and electroanalytical chemistry and offers advantages such as the extremely reduced consumption of reagents and the minimal generation of wastes. [ABSTRACT FROM AUTHOR]

In this article, we detail a paper-based three-electrode electrochemical biosensor using a mitochondria modified Toray carbon paper working electrode. Cyclic voltammetry performed on the paper-based biosensor and similar electrodes in a common laboratory setup (not in an integrated paper-based device) compare favorably. In addition, instant detection of malathion with a detection limit of 20 nM by cyclic voltammetry is demonstrated, showing the device can potentially be used as a portable platform for pesticides detection. [ABSTRACT FROM AUTHOR]

Lithium-sulfur (Li-S) batteries are a very appealing power source with extremely high energy density. But the use of a metallic-Li anode causes serious safety hazards, such as short-circuiting and explosion of the cells. Replacing a sulfur cathode with a fully-lithiated lithium sulfide (Li2S) to pair with metallic-Li-free high-capacity anodes paves a feasible way to address this issue. However, the practical utility of Li2S cathodes faces the challenges of poor conductivity, sluggish activation process, and high sensitivity to moisture and oxygen that make electrode production more difficult than dealing with sulfur cathodes. Here, an efficient but low-cost strategy for easy production of freestanding flexible Li2S-based paper electrodes with very high mass and capacity loading in terms of in situ carbonthermal reduction of Li2SO4 by electrospinning carbon is reported. This chemistry enables high loading but strong affinity of ultrafine Li2S nanoparticles in a freestanding conductive carbon-nanofiber network, meanwhile greatly reducing the manufacturing complexity and cost of Li2S cathodes. Benefiting from enhanced structural stability and reaction kinetics, the areal specific capacities of such cathodes can be significantly boosted with less sacrificing of high-rate and cycling capability. This unique Li2S-cathode design can be directly applied for constructing metallic-Li-free or flexible Li-S batteries with high-energy density. [ABSTRACT FROM AUTHOR]

The challenge of heavy metal detection for environmental, industrial and medical purposes has led to the development of many analytical techniques. Stripping voltammetry is a very sensitive electrochemical method and has been widely used for heavy metal detection. Carbon nanotubes, a well-studied carbon material with physical and chemical properties suited for electrode material is commonly employed for sensitive and selective metal detection in electrochemistry. This article reviews the recent (2011-2016) applications of carbon nanotubes as an electrode or electrode surface modifier for heavy metals detection with stripping voltammetry. [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]

A major problem coming across humanity in the early 21st century is related to environmental crises, including shortage and pollution of water sources. For this reason, extensive studies have been conducted to find effective techniques for purifying water from industrial pollutants. Advanced oxidation process (AOP) has lately caught the attention of researchers, which is an efficient, clean and contemporary method to remedy wastewater effluents. However, primitive versions of AOP methods lacked several aspects like strict pH requirements and involvement of sediments, which is why further modifications to the technique have been developed, including an electrochemical catalytic degradation approach, namely, electro‐Fenton and similar processes. This study will look through a set of novel papers investigating the application of various electrodes for the electrochemical treatment of solutions contaminated with phenol and phenolic compounds, which tried to address several shortcomings of more outdated practices and optimize the method for a set of different scenarios. [ABSTRACT FROM AUTHOR]

Rechargeable aluminum ion batteries (AIBs) have recently gained widespread research concern as energy storage technologies because of their advantages of being safe, economical, environmentally friendly, sustainable, and displaying high performance. Nevertheless, the intense Coulombic interactions between the Al3+ ions with high charge density and the lattice of the electrode body lead to poor cathode kinetics and limited cycle life in AIBs. This paper reviews the recent advances in the cathode design of AIBs to gain a comprehensive understanding of the opportunities and challenges presented by current AIBs. In addition, the advantages, limitations, and possible solutions of each cathode material are discussed. Finally, the future development prospect of the cathode materials is presented. [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 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]

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]

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]

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]

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]

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]

Due to the low price and high specific capacity, sodium ion batteries (SIBs) have become a crucial candidate for the future large‐scale energy storage power station, providing strong support for energy transition. Layered transition metal oxides (LTMOs), as one of the most promising cathode materials for SIBs, are usually accompanied by the sodiation/de‐sodiation during charging/discharging, which leads to the slippage and deformation of the layered structure, and consequently causes to the degradation of electrochemical performance. The degradation mechanisms of LTMOs attributed to the structural change are important references for improving the electrochemical performance of cathode materials. Here, this paper presents the main degradation mechanisms such as irreversible anion redox reaction, Na+/vacancy ordering transition and poor air stability as well as the corresponding modification means. It also summarizes the challenges faced by sodium‐ion LTMOs cathode materials, and gives an outlook on the key issues that need to be solved for future development. [ABSTRACT FROM AUTHOR]

BACKGROUND: Nickel foam (NF) is widely used as battery electrode matrix and electrochemical process cathode. However, the surface of NF is prone to oxidation, which may affect its ability to reduce oxygen and produce H2O2, but the influence mechanism is still unclear. In this paper, surface oxidation of the NF was regulated by pickling and drying pretreatment, and the surface oxides were characterized by X‐ray photoelectron spectroscopy (XPS) and energy dispersive X‐ray spectrometry (EDS). The NF was used as the substrate, graphite powder as the catalyst, and PTFE as the binder to prepare graphite‐coated NF composite electrodes. The effect of NF surface oxidation on their ability to generate H2O2 was investigated. RESULTS: The results demonstrated that after pickling and drying, the NF surface generated a large amount of NiO, which increased the charge transfer resistance of the NF by 20.3%, and accelerated further reduction decomposition of H2O2. The rotating ring‐disk electrode (RRDE) tests further confirmed that NiO can reduce the two‐electron oxygen reaction selectivity, which was detrimental to H2O2 electrosynthesis. The graphite‐coated NF composite electrode with pristine NF as the substrate can produce 869.1 mg L−1 of H2O2 and maintain relatively good reusability. CONCLUSION: Overall, the surface oxidation of NF is not conducive to H2O2 electrosynthesis, and it is necessary to prevent oxidation during electrode preparation. This study provides a valuable reference for the preparation of NF electrodes and can promote the further study of in situ H2O2 electrosynthesis. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Carbon materials, including graphite, hard carbon, soft carbon, graphene, and carbon nanotubes, are widely used as high‐performance negative electrodes for sodium‐ion and potassium‐ion batteries (SIBs and PIBs). Compared with other materials, carbon materials are abundant, low‐cost, and environmentally friendly, and have excellent electrochemical properties, which make them especially suitable for negative electrode materials of SIBs and PIBs. Compared with traditional carbon materials, modifications of the morphology and size of nanomaterials represent effective strategies to improve the quality of electrode materials. Different nanostructures make different contributions toward improving the electrochemical performance of electrode materials, so the synthesis of nanomaterials is promising for controlling the morphology and size of electrode materials. This paper reviews the progress made and challenges in the use of carbon materials as negative electrode materials for SIBs and PIBs in recent years. The differences in Na+ and K+ storage mechanisms among different types of carbon materials are emphasized. [ABSTRACT FROM AUTHOR]

Li/Mn‐rich layered oxide is an attractive cathode material for Li‐ion battery due to its low cost, high specific capacity, and high working potential. In this paper, the high capacity layered Li/Mn‐rich NMC cathode (Li1.2Mn0.6Ni0.1Co0.1O2) and nanocomposite blend gel polymer electrolytes (NBGPEs) are synthesized by using the sol‐gel method and solution casting technique, respectively. XRD results confirm that the cathode material has a well‐defined hexagonal layered structure. It is observed that the synthesized NBGPE containing 2 wt.% SiO2 nanofiller exhibits maximum ionic conductivity (5.2 mS cm−1), Li‐ion conductivity (~2.40 mS cm−1), and wide electrochemical stability (~5.4 V vs Li/Li+) at 30°C. The electrochemical performance of the cell (Li/NBGPE#1/Li1.2Mn0.6Ni0.1Co0.1O2) has been investigated by cyclic voltammetry and galvanostatic charge–discharge measurement. The cell delivers maximum specific discharge capacity of 212.0 mAh g−1 at 0.1C and good rate performance within 2.0‐4.8 V. At 0.2C, the cell shows stable coulombic efficiency ~98% after 200th cycle due to better interfacial stability between NBGPE#1 and the electrode. [ABSTRACT FROM AUTHOR]

Lithium metal is the key anode material for solid‐state‐batteries as its successful implementation will drastically increase their energy and power densities. However, anode contact loss during stripping leads to dendrites upon plating and subsequent cell failure. Design strategies to mitigate these issues are crucial to enable the use of lithium metal anodes. This paper reports the dissolution kinetics of composite anodes made of lithium metal and carbon nanotubes (CNTs) with a garnet‐type solid electrolyte (SE). In addition to an enhancement of the effective diffusion within the anode, its dissolution is fundamentally changed from being 2D to 3D. By maintaining contact with the SE, the CNTs facilitate lithium transport to the interface, which yields more than 20 mAh cm−2 discharge capacity at 100 µA cm−2 without the application of external stack pressure (>1 MPa). Conclusions drawn from electrochemical data on the anode microstructure are validated using cryo‐focused‐ion‐beam scanning electron microscopy and correlated with the mechanical properties. Micro‐indentation, acoustic analysis, and stress–strain testing show that mechanical properties of the anode, like yield strength and hardness, are adjustable. Overall, it is shown that the mechanical and electrochemical properties of Li–CNT composite electrodes can be tailored to suit the requirements of a practical cell. [ABSTRACT FROM AUTHOR]

The demand for energy storage devices with high energy and power densities has increased tremendously in this rapidly growing world. Conventional capacitors, fuel cells, and lithium‐ion batteries have been used as energy storage devices for the long term. However, supercapacitors are one of the most promising energy storage devices because of their high specific capacitance, high power density, and longer cycle life. Recent research has focused on synthesizing transition‐metal oxides/hydroxides, carbon materials, and conducting polymers as supercapacitor electrode materials. The performance of supercapacitors can be improved by altering electrolytes, electrode materials, current collectors, experimental temperatures, and film thickness. Thousands of papers on supercapacitors have already been published, reflecting the significance and elucidating how much demanding such energy storage devices for this fast‐growing generation. This review aims to illustrate the electrode materials loaded on various conductive substrates by electrochemical deposition employed for supercapacitors to provide broad knowledge on synthetic pathways, which will pave the way for future research. We also discussed the basic parameters involved in supercapacitor studies and the advantages of the electrochemical deposition techniques through literature analysis. Finally, future trends and directions on exploring metals/metal composites toward designing and constructing viable, high‐class, and even newly featured flexible energy storage materials, electrodes, and systems are presented. [ABSTRACT FROM AUTHOR]

Tatyana Alexandrovna Kryukova, a Russian scientist and electrochemist, made significant contributions to electroanalytical chemistry. She worked closely with Professor Aleksandr Naumovich Frumkin, a renowned Russian scientist in the field of electrochemistry. Kryukova is best known for developing the theory of polarographic maxima, which explains the sharp increase in current observed during polarographic measurements under certain conditions. She also discovered the "Kryukova effect," which is characterized by a sudden decrease in current at very negative potentials during the polarographic reduction of anionic species. Kryukova's research had both theoretical and practical implications, including its relevance to the Russian uranium project. She published numerous research papers and co-authored a comprehensive textbook on polarographic analysis. [Extracted from the article]

Electrochemical performance of cathode active materials (CAMs) is dependent on the properties of coprecipitated precursors (pCAMs). This is a sensitive process affected by several reaction parameters such as temperature, pH, concentration of reactants, agitation rate, and residence time. In this paper, the effect of parameters influencing the particle size growth and the physical properties, such as particle morphology and tapped density, was studied in the coprecipitation of Ni(OH)2. Formation of a homogeneous population with narrow particle size distribution was observed, followed by a more heterogeneous population of dense particles. Ammonia concentration and residence time had significant effects on particle size growth and morphology, but agitation rate also had an impact. [ABSTRACT FROM AUTHOR]

This paper reports the development of a simple electroanalytical method for imazethapyr (IMT) determination in rice samples based on molecularly imprinted polymer and functionalized carbon black paste electrode (MIP‐fCBPE). Carbon black (CB) was functionalized by the insertion of oxygenated functional groups upon acid treatment with HNO3 and H2SO4. The functionalized carbon black (fCB) presented higher performance for IMT determination than the CB without functionalization. The insertion of molecularly imprinted polyvinylimidazole (MIP‐VN) in the fCBPE promoted a significant increase in the cathodic peak current even at low proportions (7.5 % w/w) due to the specific binding sites for IMT recognition. For IMT determination, DPV parameters were optimized by the Doehlert matrix applying 0.1 V for 60 s as pre‐treatment in acetate buffer solution (pH 3.0) as supporting electrolyte. The proposed method showed low limit of detection (0.03 μmol L−1), a wide linear range (0.10–70.00 μmol L−1), and good precision in terms of repeatability of intraday measures (RSD%=3.6). The method was applied in rice samples after microwave‐assisted extraction of IMT and the accuracy of the method was evaluated by addition/recovery assays (96.3–105.7 %), being statistically attested using HPLC‐DAD as reference technique. [ABSTRACT FROM AUTHOR]

The influence of the size and oxidation state of Au nanoparticles (AuNPs) as electrocatalysts for the electro-oxidation of cellulose was studied. Carbon paper electrodes modified with AuNPs were used as the electrocatalysts for the electro-oxidation of cellulose dissolved in 1.3 m NaOH. The size and oxidation state of the AuNPs were determined by using SEM, TEM, and X-ray photoelectron spectroscopy. Both the size and the oxidation state of the AuNPs were found to influence the electrocatalytic properties of the electrode, as studied by using cyclic voltammetry, square wave voltammetry, and electrochemical impedance spectroscopy. The carbon paper electrodes decorated with AuNPs (less than 25 nm) that consist of metallic Au gave rise to a significantly higher electrocatalytic activity than a bare polycrystalline Au electrode. [ABSTRACT FROM AUTHOR]

In our previous paper ( Analyst, 2014, 139, 5339) we introduced the concept of the back-to-back electrochemical design where the commonly overlooked back of screen-printed electrodes are utilised to provide electroanalytical enhancements in screen-printed electroanalytical sensors. In this configuration the overall sensor comprises of a flexible polyester substrate which has a total of two working, counter and reference electrodes present on the sensor, with a set of electrodes on each side of the substrate. The sensors are designed to allow for a commonly shared electrical connection to the potentiostat and do not require any specialised connections. In this paper we demonstrate proof-of-concept extending the electroanalytical utility of the back-to-back screen-printed electrode sensors to bulk modified single-walled carbon-nanotubes and electrocatalytic cobalt phthalocyanine microband electrodes. The electroanalytical applications of these novel electrode configuration are exemplified towards the sensing of dopamine, capsaicin and hydrazine. This paper demonstrates the versatility of the back-to-back configuration where different surface modifications can be readily employed giving rise to enhancements in sensor performance. [ABSTRACT FROM AUTHOR]

Tattoo electronics is one of the emerging technologies in skin compliant biosensing. The growing interest in their large application in health monitoring raises several interrogations on how these sensors interface with the skin. In this paper, the bioimpedance at the interface of the skin and ultra‐conformable tattoo electrodes made of conducting polymers are focused on. The electrochemical characteristics of these electrodes differ from traditional gelled Ag/AgCl electrodes. The modeling of equivalent circuits in different skin‐electrode configurations proposes the explanation of the biopotentials transduction mechanism. The strong agreement between the circuit model and experimental values reveals the capacitive coupling of conducting polymer tattoo electrodes where circuit's values reflect the electrodes' and skin physical characteristics. Additional studies underline an enhanced signal stability in inter/intra‐subject evaluations using dry tattoos beneficial for broad long‐term recordings. This study provides a comprehensive explanation of the skin/tattoo electrode interface model. The understanding of this interface is essential when designing next generation wearable biomonitoring devices using imperceptible interfaces. [ABSTRACT FROM AUTHOR]

Lightweight, thin, and stretchable flexible microelectronic devices have become a new challenge for researchers. To provide power for these conformable devices, it is necessary to design the energy storage device into a flexible and stretchable structure. In this paper, a two‐step method was used to prepare a dual‐physical cross‐linked polyacrylic acid/chitosan/Ti3C2Tx(PCT) conductive hydrogel flexible electrode. The three‐dimensional (3D) porous structure not only offers a good electrical connection, but also saves the use of binder and additional current collector, which helps to enhance the electrochemical properties of electrode. The unique two‐dimensional layered structure of Ti3C2Tx enables the hydrogel electrode to withstand considerable pressure deformation without breaking, and has excellent tensile properties. The flexible electrode exhibited an excellent tensile strength of 0.083 MPa if only introduced 0.31 wt% of Ti3C2Tx with the tensile strain of 158.63% and owned remarkable self‐healing properties after injury. Thereby, the hydrogel electrode renders a maximum capacitance of 291.8 mF g−1 at 0.5 mA/g and a good cycling stability with 64.24% capacitance retention after 2000 charge–discharge cycles. This provides a research and development strategy for binder‐free, non‐toxic, and mini‐size flexible energy storage devices. [ABSTRACT FROM AUTHOR]

Lithium‐ion batteries are attracting increasing interest for a new type of green energy battery. Among many electrode materials, layered ternary LiNi1‐x‐yCoxMyO2 (M = Mn or Al) is considered a promising commercial prospect because of its low cost, excellent electrical conductivity, high discharge specific capacity, and environmentally friendly. In this paper, a ternary cathode material LiNi0.8Co0.15Al0.05O2 with high specific capacity was prepared by a two‐step solvothermal method. The effects of solvothermal time and temperature on the morphology and electrochemical properties for the electrode materials were studied. It was found that the electrochemical performance of the LiNi0.8Co0.15Al0.05O2 cathode material synthesized at 180°C for 12 hr was better. [ABSTRACT FROM AUTHOR]

This paper proposes the use of the boron-doped diamond electrode (BDDE) in flow and batch injection analysis (FIA and BIA) systems with multiple-pulse amperometric (MPA) detection for the determination of warfarin (WA) in pharmaceutical formulations. The electrochemical behavior of WA obtained by cyclic voltammetry (CV) in 0.1 mol L−1 phosphate buffer shows an irreversible oxidation process at +1.0 V ( vs Ag/AgCl). The MPA was based on the application of two sequential potential pulses as a function of time on BDDE: (1) for WA detection at +1.2 V/100 ms and; (2) for electrode surface cleaning at −0.2 V/200 ms. Both hydrodynamic systems (FIA-MPA and BIA-MPA) used for WA determination achieved high precision (with relative standard deviations around 2 %, n=10), wide linear range (2.0−400.0 μmol L−1), low limits of detection (0.5 μmol L−1) and good analytical frequency (94 h−1 for FIA and 130 h−1 for BIA). The WA determination made by the proposed methods was compared to the official spectrophotometric method. The FIA-MPA and BIA-MPA methods are simple and fast, being an attractive option for WA routine analysis in pharmaceutical industries. [ABSTRACT FROM AUTHOR]

Ni‐rich cathode materials have become one of the most promising cathode materials for advanced high‐energy Li‐ion batteries (LIBs) owing to their high specific capacity. However, Ni‐rich cathode materials are sensitive to the trace H2O and CO2 in the air, and tend to react with them to generate LiOH and Li2CO3 at the particle surface region (named residual lithium compounds, labeled as RLCs). The RLCs will deteriorate the comprehensive performances of Ni‐rich cathode materials and make trouble in the subsequent manufacturing process of electrode, including causing low initial coulombic efficiency and poor storage property, bringing about potential safety hazards, and gelatinizing the electrode slurry. Therefore, it is of considerable significance to remove the RLCs. Researchers have done a lot of work on the corresponding field, such as exploring the formation mechanism and elimination methods. This paper investigates the origin of the surface residual lithium compounds on Ni‐rich cathode materials, analyzes their adverse effects on the performance and the subsequent electrode production process, and summarizes various kinds of feasible methods for removing the RLCs. Finally, we propose a new research direction of eliminating the lithium residuals after comparing and summing up the above. We hope this work can provide a reference for alleviating the adverse effects of residual lithium compounds for Ni‐rich cathode materials' industrial production. [ABSTRACT FROM AUTHOR]

Transition‐Metal chalcogenides have high Li‐ion storage capacity and considerable cycle performance, which has attracted great interest from researchers and is expected to replace graphite materials in the field of Li ion batteries. The purpose of this paper is to find a low‐cost and ecofriendly method for producing copper‐based chalcogenides as anodes with a high capacity and long cycling stability for lithium ion batteries. In our strategy, carbon nanospheres are used as templates to prepare precursor Cu(OH)2@C. Then, the Cu(OH)2@C is converted into copper‐based chalcogenides by different routes. The structure and morphology of the as‐synthesized materials is characterized by the X‐ray diffraction, scanning electron microscopy and transmission electron microscopy. The anode electrochemical performance of the samples was investigated by galvanostatic cycling (GC) vs. Li/Li+ at different current rate. Compared to other copper chalcogenides, the synthesized copper oxide shows better charge/discharge cycle stability and rate performance. Its capacity retention is as high as 128 % at a current density of 0.5 C after 200 cycles. [ABSTRACT FROM AUTHOR]

The ternary‐layered oxide (LiNixCoyMnzO2) has become the most promising cathode material for lithium‐ion batteries due to the advantages of higher discharge platform, better conductivity, and higher theoretical capacity. The [NixCoyMnz](OH)2 with different ratios of nickel, cobalt, and manganese (NCM) was prepared by solvothermal method, and then ternary cathode material LiNixCoyMnzO2 was obtained by mixing lithium and calcining. In this paper, ternary cathode materials with different ratios of NCM were prepared by the solvothermal method. The structure and morphology of the materials were analyzed by X‐ray diffraction, scanning electron microscopy, and energy‐dispersive spectroscopy. The effects of the ratio on the electrochemical properties of the materials were investigated by constant current charge and discharge test and electrochemical impedance spectroscopy test. The synthesized lithium‐nickel‐cobalt‐manganese oxide belongs to the hexagonal system and has an α‐NaFeO2 layered structure, which is an R‐3m space group. The NCM ternary cathode materials with different morphologies were obtained by changing the ratio of NCM. The sample with NCM ratio of 5:3:2 has a unique sheet‐like spherical shape and has the best rate performance. [ABSTRACT FROM AUTHOR]

A miniaturized potentiometric saxitoxin sensor on graphene nanosheets with incorporated lipid films and Anti-STX, the natural saxitoxin receptor, immobilized on the stabilized lipid films is described in the present paper. An adequate selectivity for detection over a wide range of toxin concentrations, fast response time of ca. 5-20 min, and detection limit of 1 nM have been achieved. The proposed sensor is easy to construct and exhibits good reproducibility, reusability, selectivity, long shelf life and high sensitivity of ca. 60 mV/decade of toxin concentration. The method was implemented and evaluated in lake water and shellfish samples. This novel ultrathin film technology is currently adapted to the rapid detection of other toxins that could be used in bioterrorism. [ABSTRACT FROM AUTHOR]

The effect of nitrogen doping in the precursor sol from different nitrogen‐bearing sources on the in situ‐grown carbon film is evaluated for use as an electrode in electrochemical capacitors. The film is developed by the electrospray coating of resorcinol–formaldehyde (RF) sol on carbon fiber paper, serving as the current collector of the capacitor and subsequent curing, solvent removal, and carbonization in situ. Ethylenediamine and melamine are the aliphatic and aromatic hydrocarbonaceous sources, respectively, that are added to RF in separate experiments. The interaction between the electrolyte ions and the electrode surface is enhanced due to the presence of nitrogen and oxygen functional groups, and is analyzed through energy‐dispersive X‐ray spectroscopy, elemental CHNS analysis, Fourier transform infrared spectroscopy, and X‐ray photoelectron spectroscopy analyses. At the same time, the difference between the cross‐linking mechanism in the two cases leads to different pore structures at the micro‐ and mesoscales in the carbonized product, as reflected in the scanning electron microscope images and nitrogen adsorption–desorption data. The electrochemical performances of the electrodes are analyzed with regard to the two sets of results, referred earlier, and the relative importance of the pore hierarchy induced by cross‐linking is discussed. [ABSTRACT FROM AUTHOR]

Porous metallic sponge has shown enormous application potential in many fields including electrochemical electrode, catalysis, sensors, separation and purification, microwave and sound inhibition, etc. In this paper, we described the preparation of a class of highly compressible Ni−Co alloy‐based sponges with tailorable conductivity and soft magnetic properties as well as EMI shielding ability by employing elastic porous melamine sponge as the support. The melamine sponge was first modified by one‐step dopamine‐triggered radical polymerization reaction, in which polymer brushes with quaternary ammonium cations were grafted onto the sponge fibers for the capture of negative catalyst moieties. The immobilized catalyst moieties could subsequently induce in‐situ chemical deposition of a uniform and well‐adhesive Ni−Co alloy layer with controllable compositions and thickness on the fiber surface owing to the interpenetrating network between hydrophilic polymer brushes and the in‐situ deposited metal layer. The obtained alloy sponges show good compression‐resilience property, excellent conductivity and favorable soft magnetic performance as well as good compressive fatigue resistance during repeated compression‐release cycles, and thus can find promising applications in many fields, including pressure resistance sensors, magnetic controlled pollutant absorbents, tunable EMI shielding materials, etc. [ABSTRACT FROM AUTHOR]

Solution conductivity plays a fundamental role for the employment of electrochemical advanced oxidation processes (EAOPs) and in the determination of their energy consumption. In this paper, a conventional flow cell based on a boron-doped diamond (BDD) anode that requires the addition of supporting electrolyte, is compared with a cell setup based on solid polymer electrolyte (SPE). The new cell configuration avoids the addition of salt to increase solution conductivity. The performances of the two systems are compared for the treatment of different solutions containing methylparaben, ethylparaben and propylparaben. Both systems are able to remove all the three parabens, but the SPE-system provided a better performance, with a maximum COD removal of 91% and energy consumption of 16.25 kWhm-3, whereas the conventional system can remove a maximum of 81% consuming 10.92 kWhm-3. The influences of parameters such as current density, flow conditions and supporting electrolyte concentration were analyzed, and results confirm that the SPE system is a promising system to treat low-conductive solutions polluted by parabens. [ABSTRACT FROM AUTHOR]

In the past, the diffusion of electric vehicles (EVs) has been hindered by energy storage limits. In fact, these are the reason for the limited EV range and the consequent range anxiety of their drivers. Thanks to constant improvements in storage system technologies over the years, in terms of both energy and power density, lithium‐ion batteries (LiBs) now guarantee vehicle ranges higher than 150 km for small vehicles. Another important improvement has been achieved by the hybridisation of LiBs with other storage technologies such as electric double‐layer capacitors or lithium‐ion capacitors. By adding an additional storage unit (ASU) to the EV battery system, the overall efficiency increases, with a consequent gain in the vehicle's expected range. In a previous paper, an optimal sizing procedure was proposed, through which it is possible to calculate the optimal ASU mass that maximises the EV range for a given vehicle, ambient conditions, and driving cycle, which was considered to be known a priori. In the present work, a real‐time implementation of the control strategy on which the optimal sizing procedure was based is proposed and analysed using the results of simulation tests. [ABSTRACT FROM AUTHOR]

Microbial fuel cells (MFCs) are an important renewable energy source for underwater sensors. However, bioturbation problems cause short circuits in MFCs. Using distributed multiple anodes can effectively solve this problem. This paper presents a new power converter design that automatically detects the impaired anodes and disconnects them from the rest of the system for better energy efficiency and robustness. The evaluation was made by using 90 nm CMOS technology. The proposed power converter provides 42% more end‐to‐end efficiency than conventional design under the worst‐case scenario. [ABSTRACT FROM AUTHOR]

Despite the very high theoretical energy density, Li‐S batteries still need to fundamentally overcome the sluggish redox kinetics of lithium polysulfides (LiPSs) and low sulfur utilization that limit the practical applications. Here, highly active and stable cathode, nitrogen‐doped porous carbon nanotubes (NPCTs) decorated with NixCo1‐xS2 nanocrystals are systematically synthesized as multi‐functional electrocatalytic materials. The nitrogen‐doped carbon matrix can contribute to the adsorption of LiPSs on heteroatom active sites with buffering space. Also, both experimental and computation‐based theoretical analyses validate the electrocatalytic principles of co‐operational facilitated redox reaction dominated by covalent‐site‐dependent mechanism; the favorable adsorption‐interaction and electrocatalytic conversion of LiPSs take place subsequently by weakening sulfur‐bond strength on the catalytic NiOh2+−S−CoOh2+ backbones via octahedral TM‐S (TM = Ni, Co) covalency‐relationship, demonstrating that fine tuning of CoOh2+ sites by NiOh2+ substitution effectively modulates the binding energies of LiPSs on the NixCo1‐xS2@NPCTs surface. Noteworthy, the Ni0.261Co0.739S2@NPCTs catalyst shows great cyclic stability with a capacity of up to 511 mAh g−1 and only 0.055% decay per cycle at 5.0 C during 1000 cycles together with a high areal capacity of 2.20 mAh cm−2 under 4.61 mg cm−2 sulfur loading even after 200 cycles at 0.2 C. This strategy highlights a new perspective for achieving high‐energy‐density Li‐S batteries. [ABSTRACT FROM AUTHOR]

Gamma‐aminobutyric acid (GABA) is involved in the signal transduction and metabolism of various substances in plants. Its in vivo detection in plants is of great importance for understanding its physiological role. In this study, an ultrasensitive electrochemical immunosensor is developed for in vivo detecting GABA in plants based on screen printed electrode (SPE) electrode. Gold nanoparticles (Au NP) was electrodeposited on the SPE to improve the conductivity of the electrode. Nanocomposite of ferrocene‐Carboxylated graphene oxide‐carboxylated multi‐walled carbon nanotubes (Fc‐GO‐MWCNT) was fabricated on the electrode to improve the electrochemical properties of the sensor, and Fc was used to generate electrochemical signals. Then polydopamine (PDA) was electropolymerized on the electrode to improve the electrochemical activity of the sensor and increase the loading amount of GABA antibody. The as‐prepared immunosensor shows the widest detection range of 10 fM to 10 mM, and lowest detection limit of 1.9 fM (S/N=3) for GABA. This immunosensor was applied for in vivo detecting GABA in the cucumber leaves under salt stress. Our sensor is the first electrochemical immunosensor for in vivo detecting GABA in plant. It proposes a new strategy for the development of immunosensor for in vivo detection of biomolecules in plants. [ABSTRACT FROM AUTHOR]