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

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

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

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

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

Analystrsc. li/ analyst Volume 149 Number 15 7 August 2024 Pages 3873- 4084 ISSN 0003- 2654 PAPER William B. Veloso, Thiago R. L. C. Paixão et al. Gold fi lm deposition by infrared laser photothermal treatment on 3D- printed electrodes: electrochemical performance enhancement and application [Extracted from the article]

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

Heterointerfaces not only provide more sites for lithium ion storage, but also reduce the damage of electrode active materials, which are conducive to boosting the capacity and cycle stability of the electrode. This paper demonstrates for the first time that nanofibers with a NiO/Co3O4/NiCo2O4 heterostructure can be prepared by adjusting the annealing temperature. These heterostructured nanofibers are derived from as-spun Ni/Co nanofibers prepared by using electrospinning through thermal annealing at 500–800 °C. The phase formation and decomposition of spinel NiCo2O4 occur during heat treatment, and the composition is dependent on the annealing temperature. The electrochemical properties of the electrodes are correlated with the phase composition, particle size and morphology of the nanofibers. The nanofiber electrode annealed at 650 °C exhibits optimal electrochemical performances. Its specific capacity continues to increase at the initial stage of charge–discharge, and the activation cycle reached 61 cycles. The electrode has the largest boost value of 187.6 mA h g−1 (boost ratio, 21.08%), and its specific capacity reaches 1081.4 mA h g−1. The charge storage mechanism is analyzed by using cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic intermittent titration technique measurements. The contribution of electrode pseudo capacitance increases from 66.27% to 73.09% as the scan rate increases from 0.2 to 1.0 mV s−1, revealing that both the diffusion- and capacitive-controlled processes contributed. This is a facile and low-cost strategy to prepare high performance electrode materials for lithium-ion batteries, and stimulates the further development of phase-transition-induced synthesis of nanofibrous heterostructures. [ABSTRACT FROM AUTHOR]

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

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

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]

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]

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]

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]

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

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

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

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

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]

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]

In this work, nickel-catecholate (Ni-CAT) nanorods were in situ compounded on graphene oxide (GO) to form a composite Ni-CAT@GO (NCG) with a special "blanket-shape" structure, which was used as an electrode material for supercapacitors. The morphology of Ni-CATs in situ grown on GO was modulated by introducing various contents of GO. With increasing GO, the length of nanorods of Ni-CATs is obviously shortened, and the charge transfer resistance of NCG is significantly reduced as the GO content is relatively low while it increases with further addition of GO, because excessive GO in NCG results in smaller crystal sizes accompanied by smaller stacking pores. Both the over-long Ni-CAT nanorods and the smaller stacking pores can restrict the accessible surface areas for the electrolyte. Optimal nanorod sizes are crucial to achieve good electrochemical performance for electrode materials. Galvanostatic charge–discharge analysis of NCG electrodes shows that their capacity initially increases and then decreases with the addition of more and more GO, and Ni-CAT@GO-0.5 (NCG0.5) with minimal charge transfer resistance exhibits the best electrochemical performance. The results demonstrate that the NCG0.5 electrode with optimal morphology possesses an excellent capacitance of 563.8 F g−1 at 0.5 A g−1 and a good rate performance of 61.9% at 10 A g−1, indicating that Ni-CAT@GO is a new type of promising electrode material for supercapacitors based on conductive metal–organic frameworks. [ABSTRACT FROM AUTHOR]

NaVPO4F has become a focal point in the realm of sodium-ion battery cathode materials owing to its robust structure, elevated voltage platform, and considerable theoretical capacity. Nonetheless, the limited conductivity of NaVPO4F poses a challenge to its practical utilization. In this study, we introduce a straightforward one-step ball milling process to address this issue by creating NaVPO4F/G (G stands for graphite) and enhancing electronic conductivity through the incorporation of polyethylene glycol 6000 (PEG6K). Graphite has the capability to enhance electrochemical properties and markedly enhance electronic conductivity. Furthermore, the incorporation of PEG6K can enhance the transport stability of sodium ions at the interface of sodium-ion batteries. After optimization, NaVPO4F/G@P (P stands for PEG6K) delivers a high capacity of 128.5 mA h g−1 at 0.2C and a high rate capacity of 105.0 mA h g−1 at 10C, with a capacity retention rate of 116.0 mA h g−1 after 200 cycles. Moreover, when coupled with a HC anode (HC as the negative electrode), the full cell still displays an outstanding performance of 76.0 mA h g−1 at 20C. A simple approach is provided in our study that has the potential to significantly improve the performance of sodium-ion batteries. [ABSTRACT FROM AUTHOR]

The development prospects of conventional Li-ion batteries are limited by the paucity of Li resources. Mg–Li hybrid batteries (MLIBs) combine the advantages of Li-ion batteries and magnesium batteries. Li+ can migrate rapidly in the cathode materials, and the Mg anode has the advantage of being dendrite-free. In this study, a type of Li4Ti5O12 composite material doped with Sn4+ and a conductive carbon skeleton (Li4Ti4.9Sn0.1O12/C, Sn0.1-LTO/C) was prepared by a simple one-pot sol–gel method. The doped Sn4+ replaces part of Ti4+ in the crystal lattice, which makes Ti3+ require charge compensation, thus improving the ionic conductivity. The intervention of the conductive carbon skeleton further improves the conductivity of the Sn0.1-LTO/C composite material. The performance of Sn0.1-LTO/C as the cathode of MLIBs is explored. The initial discharge capacity was 159.1 mA h g−1 at 0.5 C, and it was maintained at 105 mA h g−1 even after 500 cycles. The excellent electrochemical performance is attributed to a small amount of Sn doping and the involvement of the conductive carbon skeleton, which indicated that the Sn0.1-LTO/C composite material provides great potential application in MLIBs. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) batteries have attracted the attention of researchers because of their excellent theoretical capacity and the advantages of cost-saving and environmental friendliness of their cathode materials. However, due to the shuttling of soluble intermediate polysulfides and other issues, the performance of current Li–S batteries is far from satisfactory. Herein, a sulfur-containing polymer (S-TVTCSi4) synthesized by the copolymerization of sulfur with 2,4,6,8-tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane (TVTCSi), was combined with carbon nanotubes (CNTs) to obtain a sulfur-containing polymer/carbon nanotube composite cathode material for Li–S batteries. S-TVTCSi4 can effectively anchor lithium polysulfide through covalent bonding, and CNTs can improve the electrochemical reaction kinetics inside the battery. As a result, the S-TVTCSi4-CNT-based battery exhibited prominent rate capacity and stable cycling performance at different current densities, the reversible capacity of 980 mA h g−1 can be achieved after 100 cycles at 0.3C, with the capacity retention of 88.3%, and even at a high current density of 1C, 64.6% of the initial capacity can be retained after 1000 cycles, with a capacity decay of only 0.035% per cycle. The impressive cycling performance demonstrated the enormous potential of the S-TVTCSi4-CNT composite cathode in high-energy Li–S batteries. [ABSTRACT FROM AUTHOR]

This paper reports the comparison of the electrochemical properties of 3D PLA-graphene electrodes (PLA-G) under different activation conditions and through different processes. In this work, the performance of the electrodes was evaluated after polishing, electrochemical and chemical treatments and a combination of them. The best results were obtained with hydroxide activation using 1.0 mol L−1 NaOH for 30 min of immersion, which promoted the saponification of PLA exposing the graphene nanoribbon structures. The improvement was more evident also after electrochemical activation, which led to a great increase in surface area, defects, electron transfer rate and amount of edge sites. The analytical performance of the proposed PLA-GNaOH-30-EC electrode was evaluated in the presence of dopamine (DA) by three electrochemical techniques, presenting a broad linear range, and limits of detection of 3.49, 2.17 and 1.67 μmol L−1 were obtained by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and square wave voltammetry (SWV), respectively. The separation and quantification of DA in the presence of AA and UA was also reported. The sensor showed good repeatability and reproducibility and was successfully applied to DA determination in synthetic urine and human serum, showing good recovery, from 88.8 to 98.4%. Therefore, the activation methods were essential for the improvement in the 3D PLA-G electrode properties, allowing graphene surface alteration and electrochemical enhancement in the sensing of molecular targets. [ABSTRACT FROM AUTHOR]

Developing eco-friendly and low-cost advanced anode materials, such as Fe2O3 and Mn3O4, is fundamental to improve the electrochemical performance of lithium-ion batteries (LIBs). The rational engineering of the microstructure of Fe2O3 and Mn3O4 to endow it with one-dimensionally and hierarchically porous architecture is a feasible way to further improve and optimize the electrochemical performance of the anode materials. Herein, we demonstrate a facile strategy to prepare nanotubular Fe2O3 and Mn3O4 as advanced anode materials for high-performance LIBs. By combining the merits of the one-dimensionally nanotubular morphology and hierarchically porous structure, limitations in the lithiation activity of Mn3O4 and Fe2O3 anode materials, such as low electrical conductivity, large volume expansion, and sluggish lithium-ion diffusion within the materials, have been effectively overcome. When used as anode materials, t-Fe2O3 and t-Mn3O4 exhibited outstanding electrochemical performances, including a high reversible discharge capacity (859.7 and 901.4 mA h g−1 for t-Fe2O3 and t-Mn3O4, respectively), excellent rate performance, and ultra-stable cycling stability. Such superior electrochemical performances proved the exceptional potential of the materials for the real-world application in LIBs. [ABSTRACT FROM AUTHOR]

Herein, a dual-mode detection system was constructed for efficient and accurate detection of bisphenol A (BPA) with the assistance of the BPA-induced hybridization chain reaction (HCR). The captured DNA (cDNA) was first modified on the surface of magnetic spheres modified with gold nanoparticles and polydopamine and then hybridized with the BPA aptamer to form double-stranded DNA (dsDNA). In the presence of the BPA target, the BPA aptamer was released from the surface of the magnetic sphere. The free cDNA triggered a HCR to construct a DNA duplex. Methylene blue (MB), as a bifunctional probe, was intercalated into the double-stranded DNA to amplify the photocurrent (IPEC) of the CdS-modified electrode and generate an electrochemical current (IEC) at the same time. Under the optimized conditions, the PEC and EC signal responses of the system were linear to the logarithm of BPA concentration in the range of 1.0 × 10−10 M to 1.0 × 10−5 M. The detection limits were found to be 1.27 × 10−11 M and 3.0 × 10−11 M using the PEC and EC methods, respectively. The constructed dual-mode biosensor exhibited good performance for real sample analysis, demonstrating its promising potential for practical applications. In addition, this dual-mode detection strategy provides more accurate and reliable detection results. [ABSTRACT FROM AUTHOR]

In order to synthesize distinctive ternary nanocomposites, this study combines nanostructured lanthanum oxide (La2O3), reduced graphene oxide (rGO), and quantum size (5–6 nm) silver nanoparticles (AgNPs). La2O3 does not aggregate when AgNPs are introduced with rGO, which also increases bioactivity for the immobilization of biomolecules. Further, effective surface contacts are made possible by the functional groups of rGO and hexagonal La2O3 nanoparticles and the large surface area of rGO increases the electrical conductivity of its electron clouds. The rGO and La2O3 (L) are conjugated with AgNPs using an ex situ hydrothermal technique to create L-rGO/Ag nanocomposites. Prepared ternary L-rGO/Ag nanocomposites have been confirmed using various characterization methods, such as XRD, FT-IR, UV-visible, PL, Raman, SEM, TEM, and EDAX. Further, the tyrosinase enzyme has been immobilized onto the L-rGO/Ag/ITO electrode for electrochemical dopamine biosensing via DPV analysis. Standard dopamine samples were investigated in the range of 1 to 95 μM and the bioelectrode displayed outstanding sensitivity of 24.32 × 10−4 mA μM−1 cm−2 for lower concentrations (1–35 μM) and 20.88 × 10−4 mA μM−1 cm−2 for higher concentrations (40–95 μM), and limit of detection (LOD) of 0.34 μM. In addition to this, the bioelectrode exhibits 40 days of stability, minimal interference, and 8 cycles of reusability without significant deterioration. Its low Michaelis–Menten constant (Km) value of 3.70 μM emphasizes its great dopamine sensitivity and affinity. Hence, the use of this bioelectrode in real sample analysis is motivated by the encouraging results in standard sample analysis of dopamine, opening possibilities for a variety of useful practical applications for timely monitoring and managing neurodegenerative disordered. [ABSTRACT FROM AUTHOR]

The electrochemical transformation of sustainable feedstocks such as biomass derived species can help to electrify the chemical industry and reduce reliance on petroleum. Furfural (FF), one such biomass derived species, can be electrochemically reduced to form furfuryl alcohol (FA) and 2-methylfuran (MF) which are used to produce thermally stable molds and resins, and a fuel candidate or additive, respectively. Using Cu electrodes allows for selective production of FA or MF, dependent on the pH of solution, with MF requiring a low pH. The highly acidic conditions to produce MF also drive homogeneous side reactions and foul the Cu electrode with time. To better understand the nature of the build up on the electrodes, accelerated fouling conditions of high initial concentrations of FF and very low pH were investigated. At concentrations of 200 mM FF in 0.5 M H2SO4, we observed fouling of the Cu electrode during electrochemical hydrogenation and hydrogenolysis (ECH) of FF. The fouling of the electrode was also shown to be potential dependent, with poly(furfuryl alcohol) (pFA) forming at −560 mV RHE while an amorphous carbon resembling soot was observed more significantly at −700 mV RHE. The fouling of the Cu electrodes was shown to increase the polarization resistance during FF reduction, hindering the rates of reactions to FA and MF. Through control studies, it was found that the fouling is electrochemically-driven and requires the starting reactant FF to be present. By investigating and understanding the fouling of Cu electrodes during the electrochemical hydrogenation and hydrogenolysis of FF, catalysts can be better designed to inhibit fouling and be used for longer durations or for more cycles before requiring a treatment to regain activity or replacement. Additionally, while this work shows the detriment of carbon fouling on the electrode, pFA is a desirable product. Process intensification through development of a FF to pFA electrochemical step could be achieved through electroreduction with high concentration of FF in 0.5 M H2SO4. [ABSTRACT FROM AUTHOR]

The Ni-rich layered oxide cathode has shown high energy density, proper rate capability, and longevity of the rechargeable battery, while poor stability and capacity fading are assumed to be its common cons. To address this obstacle, prospective cathode materials are synthesized by integrating the lithium transition metal oxides with an artificial cathode electrolyte interphase (CEI) layer. Herein, plasma-enhanced atomic layer deposition (PEALD) is employed to coat the LiNi0.8Mn0.1Co0.1O2 (NMC811) electrode with Al2O3 and MoO3. The combined results from morphological examinations revealed the formation of uniform Al2O3 and MoO3 sheets after 200 cycles of PEALD coating. Consistent results from the XRD analysis demonstrate that Al2O3 and MoO3 artificial CEIs can reduce Li–Ni mixing. The cyclic voltammetry tests show the oxidation–reduction kinetic. The modified NMC811 structures with Al2O3 and MoO3 represent a remarkable improvement in terms of capacity retention. The coated cathode with Al2O3 clearly outperforms the modified configuration with MoO3 concerning ionic conductivity, charge/discharge reversibility, and capacity retention. The promising results obtained in this study open the possibility of synthesizing Ni-rich cathodes with enhanced electrochemical performance. [ABSTRACT FROM AUTHOR]

Transition metal sulfides have broad application prospects as supercapacitor electrode materials. However, their poor structural stability and conductivity hinder improvements in their electrochemical performance. Therefore, the introduction of highly conductive carbon nanotubes (CNTs) as sulfide growth substrates is considered to improve the microstructure and electrochemical performance of electrode materials. In this study, a highly conductive CNT solution was sprayed onto a nickel foam current collector, and Co3S4/Ni0.96S was successfully constructed on a CNT conductive substrate using a combination of hydrothermal and electrochemical deposition methods, forming a unique nanosheet-covered nanotube structure Co3S4/Ni0.96S@CNTs. The addition of an appropriate concentration of CNTs can not only serve as a substrate for the growth of Co3S4/Ni0.96S, but also effectively maintain the overall nanosheet structure. Thus, the Co3S4/Ni0.96S@CNTs (2-CSNS@CNTs) have a stable structure and a wide range of electrochemical reaction sites, ensuring excellent conductivity and cycling stability. The electrode material 2-CSNS@CNTs exhibited a specific capacity of 1427.05 C g−1 at 1 A g−1. Additionally, the asymmetric supercapacitor 2-CSNS@CNTs exhibited a high energy density of 53.76 W h kg−1 at 800 W kg−1 and a capacity retention rate of 68.5% at 10 A g−1 after 1000 cycles. [ABSTRACT FROM AUTHOR]

Reasonable design and synthesis of high-efficiency nanocatalysts are of great significance for the electrocatalytic analysis of fungicides. In this paper, La-doped Nd2O3 (La-Nd2O3) nanomaterials are synthesized by a hydrothermal method and characterized via SEM, TEM, EDS, XPS and XRD. The results confirm that the trigonal Nd2O3 and La-Nd2O3 are successfully synthesized, and La is localized on the surface of the Nd2O3 lattice. Compared with Nd2O3, La-Nd2O3 nanomaterials have a larger surface area. In addition, the prepared Nd2O3 and La-Nd2O3 catalysts coated on a carbon paste electrode (CPE) are used as working electrodes to investigate their electrochemical performance for carbendazim (CBZ). Probably due to the synergistic electronic transfer process and dual-function effects of La-Nd2O3, the La-Nd2O3 modified electrode exhibits a stronger redox signal and faster electron transfer rate, thus resulting in superior electrocatalytic activity against CBZ. The proposed CBZ sensor produces a wide linear range of 0.08 to 50 μM and a low detection limit (0.027 μM, S/N = 3) by differential pulse voltammetry (DPV). Moreover, the La-doped catalyst has a long-term electrochemical activity and catalytic stability under steady state conditions, which indicates that La-Nd2O3 is a promising catalyst in electrocatalysis and sensing applications. [ABSTRACT FROM AUTHOR]

State-of-the-art electrochemical applications have recently employed various activated carbons combined with transition metal oxides as electrode materials, which exhibit superior conductivity and tailored porosity to offer rapid electron transfer. In this study, Bauhinia vahlii dead fruit-derived carbon (BVFC) integrated with cobalt oxide (Co3O4) nanoparticles was used to detect 4-nitrophenol (4-NP). The Co3O4@BVFC composite was characterized using various spectral and analytical techniques, including XRD, Raman, BET, TGA, FE-SEM, TEM and XPS. Under optimum experimental conditions, the Co3O4@BVFC-modified GCE revealed a wide linear range (0.01–140 μM), a low detection limit (5 nM), and high sensitivity (18.236 μA μM−1 cm−2) towards 4-NP detection with considerable selectivity. The excellent sensing ability of the composite was mainly due to the higher surface area and the synergistic effect between Co3O4 and BVFC. Furthermore, the Co3O4@BVFC-modified GCE applied in the real-time analysis of 4-NP in water bodies showed satisfactory recovery results (±96.50–98.60%). Results show that Co3O4@BVFC is a good candidate for 4-NP detection. [ABSTRACT FROM AUTHOR]

Urinalysis is attracting interest in personal healthcare management as part of a general move to improve quality of life. Urine contains various metabolites and the protein level in urine is an indicator of kidney function. In this study, a novel electrochemical sensing system based on boron-doped diamond (BDD) electrodes was developed for the detection of protein concentrations in human urine. BDD electrodes have the advantages of a wide electrochemical potential window and low non-specific adsorption, making them ideal for simple, rapid, and compact devices for home detection of bio-relevant substances. Coomassie brilliant blue (CBB), a dye that selectively and strongly binds to urine proteins, was found to be a redox-active indicator to show a decrease in its redox currents in relation to the concentration of protein in urine samples. Our detailed studies of BDD electrodes showed their limit of detection to be 2.57 μg mL−1 and that they have a linear response that ranges from 0 to 400 μg mL−1 in urine samples. We also investigated the detection of urine protein in different urine samples. Our results agreed with those obtained using conventional colorimetric analysis. We believe this to be the first study of electrochemical detection of urine protein in urine samples on BDD electrodes, which is of great significance to be able to obtain results with electrical signals rapidly compared to conventional colorimetric analysis. This CBB–BDD technique has the potential to assist healthcare management in the form of a rapid daily diagnostic test to judge whether a more detailed examination is needed. [ABSTRACT FROM AUTHOR]

The transformation from LiNi1−x−yCoxMnyO2 (NCM) cathodes to Co-free LiNi1−xMnxO2 (NM) cathodes is considered as an effective solution for the electric vehicle (EV) industry to deal with the high cost of cobalt. However, severe Li/Ni disorder, structural instability and poor cycling stability are the main obstacles to their practical application. Al doping has proven to be an effective method to improve the electrochemical performance of Ni-rich NCMs. However, with regard to Ni-rich Co-free NM cathodes, the influence of Al doping on the structural stability and electrochemical performance of NM cathodes is still not clear. In this work, Al doped LiNi0.8Mn0.2−xAlxO2 cathodes are designed and their structural stability and electrochemical performance are investigated by a combination of XRD, SEM, TEM, CV, GITT, cycling testing and EIS techniques. As a result, Al doping can effectively inhibit Li/Ni disorder and improve the structural and thermal stability. In detail, 5% is the optimal doping amount for LiNi0.8Mn0.2O2 cathodes to obtain the best electrochemical performance and the LiNi0.8Mn0.15Al0.05O2 cathode shows an excellent capacity retention of 91.97% after 300 cycles at 3.0–4.3 V. This work provides an effective strategy for the development of Ni-rich Co-free NM cathodes. [ABSTRACT FROM AUTHOR]

Prussian blue analogues (PBAs) have been considered as promising host frameworks for charge carriers because of their well-defined diffusion channel along the 〈100〉 direction. Among PBA families, Berlin green (BG) would be an ideal cathode platform because the empty carrier ion sites and two redox couples (Fe3+/2+–CN–Fe3+/2+) in the BG framework can deliver high specific capacity during battery operation. Nonetheless, in most solution-based precipitation processes, BG crystals are synthesized in irregular shapes rather than in well-defined cube shapes, thus limiting their capacities at high rate operations. In this work, given the aforementioned challenges, a simple two-step precipitation process to synthesize cubic BG without using any chelating agents and toxic acids was reported. Notably, an intermediate phase was identified as an important stage in converting irregularly shaped BG to cubic BG by releasing crystal water molecules from the framework. Utilizing well-aligned 〈100〉 channels in the cubic framework, cubic BG exhibits excellent electrochemical properties as a cathode for lithium-ion batteries, delivering a specific capacity of 107.2 mA h g−1 at a high current density of 500 mA g−1. A combined study of in situ X-ray diffraction and X-ray absorption fine structure analyses would provide a comprehensive structure–property relationship of BG cathodes. [ABSTRACT FROM AUTHOR]

Advances in the instrumentation and materials for photopolymerization 3D printing aided the use of this powerful technique in the fabrication of microfluidic devices. The costs of printers and supplies have been reduced to the point where this technique becomes attractive for prototyping microfluidic systems with good resolution. With all the development of multi-material 3D printers, most of the microfluidic devices prepared by photopolymerization 3D printing are based on a single substrate material. We developed a digital light processing multi-material 3D printer where two or more resins can be used to prepare complex objects and functional microfluidic devices. The printer is based on a vat inclination system and embedded peristaltic pumps that allow the injection and removal of resins and cleaning step between material changes. Although we have built the whole system, the modification can be incorporated into commercially available printers. Using a high-resolution projector, microfluidic channels as narrow as 43 μm were obtained. We demonstrate the printing of multi-material objects containing flexible, rigid, water-soluble, fluorescent, phosphorescent, and conductive (containing PEDOT or copper nanoparticles) resins. An example of a microfluidic chip containing electrodes for electrochemical detection is also presented. [ABSTRACT FROM AUTHOR]

Layered cathode materials are widely used in conventional lithium-ion batteries with liquid electrolytes. From LiCoO2 (LCO) to Ni-rich (LiNixCoyMnzAl1−x−y−zO2, x ≥ 0.8) materials, different electrochemically active elements bring various properties to the cathodes and therefore they are employed in different fields. Although these layered material systems, composed of different transition metals (TMs), have been intensively studied, their electrochemical properties and interfacial stabilities when paired with promising sulfide solid electrolytes have not been systematically explored. Here, excluding the interference of redundant TMs, we prepared LiNixCo1−xO2 in an attempt to reveal the laws of reactivity at the interface between the layered cathode and the sulfide electrolyte. As a result of systematic analysis, overall, both chemical and electrochemical adverse reactions are proven to be aggravated with the increasing Ni/Co proportion. Compared to that when paired with liquid electrolytes, materials with a high Ni content exhibit much inferior electrochemical stability when paired with sulfide solid electrolytes. The introduction of Co enhances the interfacial stability, whereas the effect becomes less pronounced when the Co content in the system is half or more. This fundamental work deepens the insight into cathode/electrolyte interface deterioration and serves as a guide for designing an appropriate cathode for the up-and-coming all-solid-state lithium batteries (ASSLBs). [ABSTRACT FROM AUTHOR]

There is an increasing demand for high energy density lithium-ion battery cathodes such as LiNi0.5Co0.2Mn0.3O2 (NCM523); however, severe capacity fading, and structural instability have limited their widespread application. In this study, the effect of surface modification with Li0.33La0.56TiO3 (LLTO) and its crystallinity on the electrochemical performance of NCM523 cathode materials was investigated. Scanning and transmission electron microscopy observation showed a uniform distribution of 3 and 5 wt% LLTO coating, but agglomeration was observed in a higher coating content. According to the electrochemical tests, the amorphous LLTO coating improved the cycling performance and rate capability of the NCM523 cathode. The 5 wt% amorphous LLTO-coated cathode showed the highest discharge capacity after 30 cycles at 0.1 C and after 100 cycles at 0.5 C (136.3 and 104.6 mA h g−1); significantly higher than that of the pristine NCM523 cathode (98.5 and 62.5 mA h g−1). The discharge capacity of this coated sample at 5 C was also much higher than that of the pristine cathode (106.8 compared to 78.5 mA h g−1). In addition, 5 wt% of the amorphous LLTO coating shifted the exothermic peak of the NCM523 electrode from 249 to 281 °C, indicating enhanced safety after the coating process. Compared to the crystalline LLTO-coated NCM523, the cathode with amorphous coating delivered a higher discharge capacity over cycling and at different C-rates. In light of the results, it is evident that surface modification with an amorphous LLTO coating could be a promising approach for industrial application of NCM523 cathode materials. [ABSTRACT FROM AUTHOR]

For obtaining high-performance lithium-ion batteries, it is important to develop new cathode materials with high capacity. Herein, a one-dimensional coordination polymer [Co(4-DTBPT) (DMF)2(H2O)2] (4-DTBPT) (C10H4O8) (Co-DTBPT) (4-DTBPT = 2,7-di(4H-1,2,4-triazol-4yl)benzo[lmn][3,8] phenanthroline-1,3,6,8-(2H,7H)-tetraone; DMF = dimethylformamide) was synthesized and its electrochemical performance as the cathode material of lithium-ion batteries was first investigated. The Co-DTBPT electrode showed better cycling stability and a specific capacity of 55 mA h g−1 at 50 mA g−1 after 50 cycles, and the coulombic efficiency was close to 100%. The capacity contribution of the Co-DTBPT electrode may be ascribed to the redox reaction of the Co(II) ion and the 4-DTBPT ligand in the process of charge and discharge. Our work proves once again that using one-dimensional coordination polymers as cathode materials for lithium-ion batteries is a feasible way. [ABSTRACT FROM AUTHOR]

Solid electrolyte interphases (SEIs) formed on the surface of anode materials are of great importance for high rate and long-life cycling stability. To address this issue, electrolyte additives have been widely used in lithium-ion batteries (LIBs) to modify the electrode–electrolyte interface properties. Herein, vinylene carbonate (VC) has been adopted as an effective additive to form a solid and stable SEI on Li3VO4 (LVO) anodes during cycling. We extensively investigated the fundamental characteristics of the constructed SEI layers and the related electrochemical reaction kinetics involved in the LIB environment. It was found that the introduction of VC into electrolytes could apparently enhance the rate capability and significantly improve the long-term cycling performance of Li3VO4 anodes. The obtained LVO in the electrolyte with the addition of VC exhibits a high reversible capacity of 810.4 mA h g−1, high rate performance of 521.2 mA h g−1 at 5.0 A g−1 and excellent cycling stability with 82.9% capacity retention for 2000 cycles at 10.0 A g−1. This work demonstrates that the formation of an appropriate SEI on the surface of LVO is necessary for the improvement of the electrochemical performance. [ABSTRACT FROM AUTHOR]

Li-rich antiperovskite (Li2Fe)SO with its high specific capacity is an attractive cathode material for Li-ion battery applications. While many battery materials depend on hazardous substances and their production is also rarely sustainable, we present an environmentally friendly and sustainable approach for the synthesis of Li-rich (Li2Fe)SO using mechanochemistry based on ball milling. This one step process enables preparing a large quantity of phase-pure (Li2Fe)SO using low-cost and non-toxic precursors, making it a viable alternative to current solid state synthetic method in terms of simplicity, laboratory safety and scalability. The obtained micro-sized particles are nearly spherical and have a small size distribution. To control the crystallinity and reduce the intrinsic defects of the ball-milled (Li2Fe)SO material, a post-heat treatment procedure was tested. Thermodynamic measurements confirmed the high thermal stability of the ball-milled (Li2Fe)SO material. Increasing the ball to powder weight ratio was found to be an effective strategy to decrease the milling time required for the synthesis, thus promoting energy saving. Overall, this work provides a practical guide for the green and scalable production of (Li2Fe)SO cathode material, as well as a method for particle modification for improved electrochemical properties. [ABSTRACT FROM AUTHOR]

Currently, the preparation of high-performance electrode materials is urgently needed for supercapacitors. As a new kind of organic porous material, covalent organic frameworks (COFs) with an ordered pore structure, a high specific surface area and designability, have shown great potential application value as electrode materials for supercapacitors. However, their potential application in supercapacitors is limited by the poor conductivity of COFs. Here, we in situ grew the highly crystalline triazine-based covalent organic framework DHTA-COF on a modified -Al2O3 substrate to obtain the composites Al2O3@DHTA-COFs. Some of the obtained Al2O3@DHTA-COF composites can maintain some degree of crystallinity, good stability and a vesicular structure. Compared to the precursors -Al2O3 and DHTA-COF, the 50%Al2O3@DHTA-COF composite has superior electrochemical properties as electrode materials for supercapacitors. Under the same conditions, the specific capacitance values of 50%Al2O3@DHTA-COF (261.5 F g−1 at 0.5 A g−1) are 6.2 and 9.6 times higher than the values of DHTA-COF and -Al2O3–CHO, respectively. Additionally, the 50%Al2O3@DHTA-COF electrode material exhibited long-term cycling stability even after 6000 charge–discharge cycles. The study can provide some reference for the development of COF-based composite materials for energy storage. [ABSTRACT FROM AUTHOR]

Energy storage devices (ESDs) need designing and development of high electrochemical performance and promising electrode materials. Transition-metal chalcogenides (TMCs) are being actively investigated as the electrode for electrochemical ESDs. Herein, we report the design, synthesis, and electrochemical properties of the MnSe electrode by a facile hydrothermal method. The as-synthesized MnSe electrode has a flower-like morphology with the planes growing perpendicular to its center. The results of electrochemical performance testing indicate that the pseudocapacitive nature of the MnSe electrode has a critical effect on those properties. The MnSe electrode exhibits a specific capacitance of 423.1 F g−1 at a current density of 1 A g−1 and better cyclic stability among 3000 cycles. The synthesis of MnSe electrodes opens up opportunities for the design of TMCs electrode materials and the development of supercapacitors. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) batteries have attracted great research attention because of their high energy density and low cost. However, shuttling effects of polysulfides and insulation from elemental sulfur hinder their practical application. Herein, we report hollow carbon nanofibers filled with carbon nanotubes (denoted as HCNF/CNT) as host materials for sulfur to mitigate the shuttling behavior and improve the kinetics of insulative sulfur. The as-prepared HCNF/CNT with nano-conductive domains in the hollow carbon nanofibers enables high loading and efficient utilization of sulfur. Owing to their unique structural superiority, the sulfur-encapsulated HCNF/CNT cathode materials for Li–S batteries deliver excellent electrochemical performance, including high specific capacity of 1156 mA h g−1 at 0.2 C, good rate performance and cycling stability with a capacity retention of 77.2% after 200 cycles at 2 C. Such a unique structure can provide inspiration for the rational structural design of carbon materials as hosts for high performance Li–S batteries. [ABSTRACT FROM AUTHOR]

Transition metal-based binary and ternary compound arrays were directly grown on a porous Ni foam substrate using a facile one-step hydrothermal method. Transition metals are considered ideal electrode materials for faradaic capacitors because they exhibit a wide range of oxidation states enabling effective redox charge transfer. Furthermore, compounds in which two or more transition metals react can help increase the number of active sites for charge–discharge reactions and provide more valence changes for improved charge transfer. In this work, we fabricated ternary electrodes with Ni, Cu, and Zn ions, exhibiting a larger surface area and higher entropy than those made with binary compounds. The NixCuyZnz-based ternary electrode had a shorter diffusion path for the electrolyte ions owing to its larger surface area. Ternary compounds can increase the entropy of the electrode because of the reaction between atoms of different sizes, bringing about a synergistic effect for high characteristic electrochemical values. The optimized Ni x Cu y Zn z (CO3)(OH)2 compound showed a maximum specific capacity of 344 mA h g−1 at a current density of 3 A g−1, which was remarkably higher than that of the binary electrode, and a cycling stability of 84.9% after 5000 cycles. An asymmetric supercapacitor produced with this compound as the positive electrode and graphene as the negative electrode exhibited a high energy density of 36.2 W h kg−1 at a power density of 103.1 W kg−1 and a current density of 2 A g−1. The asymmetric supercapacitor fabricated using the Ni x Cu y Zn z (CO3)(OH)2 compound as the positive electrode exhibited excellent electrical properties when used in an illuminated LED device. [ABSTRACT FROM AUTHOR]

The nanoscale Li2Mn0.8Ni0.2SiO4/MnO2 composite was successfully prepared via a two-step method. Firstly, by the preparation of MnO2 nanoparticles through an oxidation-reduction reaction; secondly, by synthesizing Li2Mn0.8Ni0.2SiO4 using an EDTA-assisted sol–gel method; finally, the two nanoparticles mixed together by hand milling to form the nanocomposite. The synthesized nanoparticles were characterized using several techniques. The nanocomposite presents a well-developed orthorhombic crystal structure with a Pmn21 space group, although there are small impurities of MnO and Li2SiO3. The BET surface area measurements indicate that all the prepared materials are mesoporous. The effect of nanoscale MnO2 on the electrochemical properties of the Li2Mn0.8Ni0.2SiO4 nanomaterials was evaluated. The composite (denoted as (LMNS/M2) exhibited a specific capacity of 962.4 C g−1 at the current density of 2 A g−1. Furthermore, a hybrid device using this composite as a cathode and commercial activated carbon (AC) as an anode was fabricated to examine the practical aspects of the novel electrode, which conducted a specific energy of 38.1 W h kg−1 at a specific power of 938.4 W kg−1. It preserved a capacity of 84% after 2000 cycles. Li2Mn0.8Ni0.2SiO4/MnO2 is a promising candidate for high-efficiency energy storage electrode materials for supercapacitor applications because of its superior performance and ease of preparation. The obtained results confirm the excellent electrochemical performance of the electrode as a promising electrode for energy storage applications. [ABSTRACT FROM AUTHOR]

Rational construction of nanosized anode nanomaterials is crucial to enhance the electrochemical performance of lithium-/sodium-ion batteries (LIBs/SIBs). Various anode nanoparticles are created mainly via templating surface confinement, or encapsulation within precursors (such as metal–organic frameworks). Herein, low-content SnO2 nanodots on N-doped reduced graphene oxide (SnO2@N-rGO) were prepared as anode nanomaterials for LIBs and SIBs, via a distinctive lattice confinement of a CoAlSn-layered double hydroxide (CoAlSn-LDH) precursor. The SnO2@N-rGO composite exhibits the advantagous features of low-content (17.9 wt%) and uniform SnO2 nanodots (3.0 ± 0.5 nm) resulting from the lattice confinement of the Co and Al species to the surrounded Sn within the same crystalline layer, and high-content conductive rGO. The SnO2@N-rGO composite delivers a highly reversible capacity of 1146.2 mA h g−1 after 100 cycles at 0.1 A g−1 for LIBs, and 387 mA h g−1 after 100 cycles at 0.1 A g−1 for SIBs, outperforming N-rGO. Furthermore, the dominant capacitive contribution and the rapid electronic and ionic transfer, as well as small volume variation, all give rise to the enhancement. Precursor-based lattice confinement could thus be an effective strategy for designing and preparing uniform nanodots as anode nanomaterials for electrochemical energy storage. [ABSTRACT FROM AUTHOR]