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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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

A straightforward carbothermal reduction method was used to synthesize nitrogen-doped carbon-coated LiFePO4 with the carbon and nitrogen sources derived from gelatin. Compared to the bare material, the particles of LiFePO4 composites are smaller, the electrical contact between the grains is improved, and lithium ions diffuse more rapidly in the composites. As a consequence, the structural stability and conductivity are enhanced in LiFePO4 compounds. After 500 cycles, the material delivered 138.2 mA h g−1 at a multiplicity of 1C with 90.2% capacity retention. This result demonstrates that a suitable amount of N-doped carbon layer can enhance the electrochemical performance of LiFePO4. This efficient strategy provides a facile approach to develop excellent performance LiFePO4 materials with promising practical applications. [ABSTRACT FROM AUTHOR]

Amorphous porous carbon with a network structure composed of nanosheets was prepared from semi-coke by a facile molten salt method. The low-melting eutectic salts act as solvents at 600 °C, and the porous carbon was obtained in a liquid reaction environment. Meanwhile, the effects of temperature on morphology and electrochemical performance of the carbon materials were studied. The electrodes exhibit extraordinary electrochemical performance as anodes for lithium-ion batteries and show a high capacity of 539.9 mA h g−1 at 0.2 A g−1 after 150 cycles. Moreover, the medium surface area of carbon nanosheets contributes to the high initial Coulombic efficiency of 72.9%. More importantly, the sample shows an excellent cyclability of 231.1 mA h g−1 at 2 A g−1 after 500 cycles. The superior electrochemical performance can be attributed to the unique structure accelerating the movement of electrons/ions and the permeation of the electrolyte, and the cross-linked network structure shortening the Li+ migration path. This method is simple, environmentally friendly, and has broad application prospects in the preparation of carbon-based anode materials. [ABSTRACT FROM AUTHOR]

Flower-like nanosheets of pure molybdenum disulfide (MoS2) and Fe-doped MoS2 (FM) with 2, 4 and 8% atomic-doped iron of FM-2, FM-4 and FM-8, respectively, were successfully synthesized using the hydrothermal method. The effect of iron doping on the MoS2 morphology, composition, and supercapacitor behavior are systematically investigated. In the Fe-doped MoS2 samples, iron atoms replaced the molybdenum atoms in the MoS2 structure through the hydrothermal process. Cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) measurements were conducted on a three-electrode system to evaluate the electrochemical performance of the electrodes. The specific capacitance of the FM-2 electrode was 240 F g−1 at a 10 mV s−1 CV scan rate, which was higher than that of the pure MoS2 and the other two Fe-doped MoS2 electrodes. Furthermore, EIS tests exhibited that doping iron in the MoS2 structure contributes to a rapid decline in charge transfer resistance and, therefore, a higher probability of energy storage. The results revealed that the synthesized Fe-doped MoS2 samples are potential electrode materials for future energy storage devices. [ABSTRACT FROM AUTHOR]

An electrochemical sensing electrode based on titania (anatase) and silica nanospheres (TiO2@SiO2 NSs) loaded on a pencil graphite electrode (TiO2@SiO2NSs/PGE) was fabricated and scrutinized for L-ascorbic acid detection. The PGE surface was designed by coating the nanospheres using the drop casting method. NSs and modified electrodes were investigated structurally, optically and morphologically using various characterization techniques. An electrochemical study was performed via cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA). Further, the designed electrode performance was optimized by varying pH, potential and scan rates. The TiO2@SiO2NS/PGE-modified electrode showed a high sensitivity of 2696.9 μA mM−1 cm−2 and a lower detection limit for ascorbic acid. The modified electrode also revealed a linear range of 50–2500 μM with a regression coefficient of R2 = 0.9932. Additionally, the electrode exhibited high stability and good anti-interference capability. Similarly, the modified electrode performed well in real samples for ascorbic acid detection. Furthermore, TiO2@SiO2 NSs performed very effectively against harmful microbes including Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus and Shigella flexneri bacteria with good inhibition. [ABSTRACT FROM AUTHOR]

Aprotic Li–O2 batteries possess extremely high theoretical energy density among all existing rechargeable battery systems. Thus, they are considered one of the most potential next-generation energy storage devices. Nevertheless, the lithium (Li) dendrites at the anodic side and the sluggish oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) kinetics at the cathodic side of Li–O2 batteries greatly limit their practical applications. Herein, we put forward a dual-functional carbon nanofibrous skeleton decorated with Co nanoparticles and Co-Nx sites to ameliorate the electrochemical behavior of both anode and cathode in Li–O2 batteries. The synergistic effect of Co nanoparticles and Co-Nx sites could convert carbon fibers from lithiophobic to lithiophilic, which is beneficial to decrease polarization and moderate the dendritic formation at the Li metal anode. Moreover, Co nanoparticles and Co-Nx sites as active sites can promote the ORR and OER processes (especially the OER process) at the cathodic side. Accordingly, Li–O2 batteries composed of Co/CNF-750 cathodes and Co/CNF-750 interlayer-modified Li metal anodes displayed a low discharge-charge gap of 1.004 V and long cycle life of 160 cycles under a limited capacity of 500 mA h g−1 at a current density of 200 mA g−1. This work offers an effective strategy to simultaneously deal with barriers both in the O2 cathode and Li anode for the application of Li–O2 batteries. [ABSTRACT FROM AUTHOR]

A simple method for the preparation of carbon/Sn/Helical carbon nanofiber (C/Sn/HCNF) composite by a solution phase synthesis and carbon thermal reduction is introduced, and the composite exhibits good electrochemical performance as an anode for lithium-ion batteries (LIBs). Sn nanoparticles (about 10-15 nm) are grafted onto the surface of HCNFs and coated by a carbon film with a thickness of 10-20 nm. C/Sn/HCNF anode materials can retain a capacity of 610.3 mA h g-1 after 200 cycles at a current density of 200 mA g-1, which is significantly better than 87.2 mA h g-1 by Sn and 241.2 mA h g-1 by Sn/HCNFs at the same rate. The excellent performance and simple preparation method enable the C/Sn/HCNF composite as a potential anode material for LIB application. [ABSTRACT FROM AUTHOR]

The preparation of an environmentally benign, inexpensive supercapacitor electrode material from waste biomass, achieving useful carbon electrode production, is challenging. The present work aims to find a process for recycling spent mushroom compost into a useful supercapacitor electrode material. Highsurface- area activated carbon derived from spent mushroom compost (SMC) is used as a catalyst electrode in a solid-state electrochemical double-layer capacitor (SSEDLC). The SMC is thermally activated at three different temperatures (SMC-700, SMC-800, and SMC-900) to achieve the optimal carbon content and activation temperature for improving electrode performance based on the surface area and pore structure. The SMC-derived nanostructured carbon exhibited a high specific surface area of 690 m² g-1 in the case of SMC-800 upon activation, which strongly influences the specific and areal capacitance of the fabricated SSEDLC. Interestingly, the use of the prepared PVA/H2SO4 gel electrolyte showed a promising trend, with considerable capacitance retention of up to 90% over 3000 cycles obtained with the material optimized at 800 1C (SMC-800). [ABSTRACT FROM AUTHOR]

In this study, a simple and effective method was presented for the preparation of binder-free conducting polymer/metal oxide binary composite electrode materials. The novel electropolymerizable thiophene monomer, 3-[(2,2′:5′,2′′-terthiophen-3′-yl)]-2-cyanoacrylic acid) (SDOGA), was specifically designed to fabricate homogeneous and chemically stable redox-active composite electrodes for pseudocapacitor applications. Poly(3-[(2,2′:5′,2′′-terthiophen-3′-yl)]-2-cyanoacrylic acid) (PSDOGA) was electrochemically deposited on stainless steel substrates and modified with TiO2 and V2O5 particles via a simple, efficient and low-cost process without any polymeric binder. Cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS) techniques were used to study the pseudocapacitive properties of PSDOGA/TiO2 and PSDOGA/V2O5 binder-free binary composites in both three-electrode and two-electrode cell configurations. PSDOGA/TiO2 and PSDOGA/V2O5 composites delivered high specific capacitances of 396.4 Fg−1 and 444.5 Fg−1, respectively, at 2.5 mA cm−2 current density in single electrode measurements. Symmetrical supercapacitor devices assembled by using PSDOGA/TiO2 and PSDOGA/V2O5 binder-free binary composite electrodes exhibited satisfactory energy (78 W h kg−1 and 94.8 W h kg−1) and power (700 W kg−1 and 736 W kg−1) densities with good charge/discharge characteristics at a large operating voltage of 1.85 V. Furthermore, symmetric type supercapacitor cells achieved an excellent capacitance retention of 87% and 90% for 12 500 consecutive galvanic charge/discharge cycles at a constant current density of 2.5 mA cm−2. The experimental results revealed that the cooperation between conducting polymer film and metal oxide particles not only greatly enhanced the capacitive performances, but also improved the long-term charge/discharge stability of the redox-active electrode materials. [ABSTRACT FROM AUTHOR]

Ni-rich layered cathode materials have large reversible capacity. However, they suffer from the cracking of the spherical particles, low Coulombic efficiency and fast capacity decay during cycling. Preparing a single-crystal Ni-rich cathode is a promising method to solve this problem due to its excellent structural stability. However, the morphology and electrochemical performance of single-crystal Ni-rich cathodes depend largely on the particle size and morphology of the hydroxide precursors. In this work, a suitable hydroxide precursor to synthesise single-crystal NCM622 with great dispersity and remarkable electrochemical performance is explored. Besides, the influence of grain size on the structural and thermal stability of the Ni-rich cathode material is further investigated. This work provides a reference to synthesize single-crystal Ni-rich cathodes with high electrochemical performance for lithium-ion batteries of the next generation. [ABSTRACT FROM AUTHOR]

Electrode materials exhibiting higher structural stability and electrochemical activity remain a priority in improving the electrochemical performance of supercapacitors (SCs). Herein, we report the design and synthesis of a novel nanoplate-on-nanosheet architecture with vertically aligned ZnCo2O4 (ZCO) porous nanoplates anchored on ultrathin delaminated-Ti3C2 (d-TC) nanosheets as a high-performance electrode for electrochemical SCs. The unique robust nanoplate-on-nanosheet adhesion promises fast electron and ion transport, large electroactive surface area, and excellent structural stability. Importantly, benefiting from the features of such a configuration, the ZCO/d-TC-350 composite electrode displays a high specific capacity of 195.8 C g−1 at a current density of 1 A g−1. Moreover, the constructed hybrid supercapacitor (HSC) consisting of ZCO/d-TC-350‖‖active carbon (AC) achieves a high energy density of 15.6 W h kg−1 at a power density of 551.1 W kg−1 and superior long-term stability with 89.5% capacitance retention after 4000 cycles. This work provides a promising strategy for the preparation of advanced MXene-based electrodes for electrochemical capacitors. [ABSTRACT FROM AUTHOR]

In this study, two-dimensional MXene Ti3C2Tx was modified on a glassy carbon electrode (GCE) to improve its performance for electrochemical detection. The morphology and structure of Ti3C2Tx were characterized by SEM and TEM. A new modified electrode was then fabricated by coating MXene solution on GCE for quercetin detection. The performance of MXene/GCE was determined by various methods, which showed an enhanced electrochemical activity. Direct electrochemistry of quercetin was investigated, and a pair of well-shaped redox peaks appeared with a peak-to-peak separation of 67 mV. The detection of quercetin by this proposed electrode was studied in detail, and presented a lower detection limit of 33 nM (3S0/S) with electrochemical parameters such as the electron transfer number (n), electron transfer coefficient (α) and reaction rate constant (ks) calculated as 1.99, 0.65 and 0.29 s−1, respectively. MXene/GCE was successfully utilized for the analysis of quercetin content in Ginkgo tablet samples with recoveries from 100.92% to 104.66%. Besides, MXene/GCE showed good anti-interference performance, good stability and reproducibility for the detection of quercetin. [ABSTRACT FROM AUTHOR]

Biochar (BC) is a kind of carbon-rich, renewable and low-cost material, which can be prepared from various organic materials. In this work, biochar was used as the electrode material to prepare a novel rolled electrode as a cathode for the Electeo-Fenton (EF) system. The results showed that a quite high generation of H2O2 (609 mg L−1) could be obtained on the optimum-mixed cathode of carbon black and biochar (BC–CB-(1 : 1)) at a low electric energy consumption (EEC) (32.8 kW h kg−1). Furthermore, the operating parameters such as airflow rate, pH, and current density, affecting the H2O2 electro-generation, were investigated and optimized. The optimum conditions for H2O2 generation were air flow rate 0.6 L min−1, current density 32 mA cm−2 and initial pH 7.0. The achieved removal rate of tetracycline was 95.3% within 10 min, and the TOC mineralization could reach 91% on the optimum mixed cathode, which was much higher than that of raw biochar cathode. In terms of stability, the mixed cathode remained stable after 10 cycles. The optimized design considerably improved the electrochemical performances of the electrode, which offer a cost-effective strategy for organic pollutant removal by the EF process. [ABSTRACT FROM AUTHOR]

Simple chemical synthesis is highly efficient to develop metal oxide composites as active electrode materials for an electrochemical sensor displaying enhanced catalytic sites, fast kinetics, and easy accessibility to target molecules. In this work, a cobalt oxide/tin oxide (Co3O4/SnO2) composite was prepared by a facile co-precipitation method and employed for the voltammetric determination of ornidazole (ODZ). The structural and morphological properties of the as-synthesized materials were studied through XRD, FT-IR, BET, FE-SEM, TEM, and XPS analyses. The electrochemical activity was investigated using cyclic voltammetric (CV) and linear sweep voltammetric (LSV) techniques. The electrochemical signal shows that the modified glassy carbon electrode (Co3O4/SnO2/GCE) revealed superior sensing ability in rapid ODZ detection compared to a single component of Co3O4 or SnO2. The performance was investigated over a wide linear range of 0.2 to 1185.8 μM with a low detection limit of 0.059 μM for ODZ, respectively, at a low-cost Co3O4/SnO2 modified electrode. Good selectivity was observed in the presence of NFT, 2-NA, and Cd2+ by the ODZ sensor. Furthermore, the excellent stability, repeatability, and reproducibility suggest that the constructed electrode based on Co3O4/SnO2/GCE is promising for real-time application in water samples. [ABSTRACT FROM AUTHOR]

Amorphous Al2O3-coated spinel LiMn2O4 cathode materials were prepared via a simple combustion method at a low temperature using glucose as a fuel. The morphology and structure of all samples were characterized by X-ray diffraction (XRD) analysis and transmission electron microscopy (TEM). The thickness of the amorphous Al2O3-coating is about 5 nm. Moreover, the typical spinel structure of the LiMn2O4 exhibits no change after coating Al2O3. Electrochemical characterization showed that the Al2O3-coating can improve the cycling and high current rate performance of the LiMn2O4; in particular, the 1.0 wt% Al2O3-coated LiMn2O4 cathode revealed a high initial discharge capacity of 120.4 mA h g−1 and a good cycling stability with a capacity retention of 93.52% after 100 cycles at 1 C. Moreover, an excellent high rate performance with an initial capacity of 84.2 mA h g−1 and a capacity retention of 76.96% after 1000 cycles are also obtained at 10 C. [ABSTRACT FROM AUTHOR]

Compared with the use of the environmentally harmful binder polyvinylidene fluoride (PVDF) in Li-ion batteries (LIBs), water-based binders have many advantages, such as low cost, abundant sources, and environmental friendliness. In this study, various green water-based binders and binder couples for preparing LiFePO4/C (LFP/C) cathodes in LIBs were first investigated systematically. Electrochemical tests indicated that electrodes with SA (E-SA) and electrodes with CMC/PTFE (E-CMC/PTFE) had outstanding performance. Especially in the rate performance (2C/0.1C), the values of E-SA and E-CMC/PTFE were 86.3% and 85.7%, i.e., 4.4% and 3.8% higher than those of electrodes with PVDF (E-PVDF) (81.9%), respectively. After 50 cycles, the discharge specific capacity of E-SA and E-CMC/PTFE was stable at 165 and 166 mA h g−1 (the theoretical value of LFP is 170 mA h g−1). All Rct (charge-transfer reaction resistance) values with water-based binders were smaller than the one with PVDF. E-SA, E-CMC/PTFE, and E-CMC/SA had smaller polarization than E-PVDF. E-SA and E-CMC/PTFE had an enhanced kinetics capability in Li+ transfer, which may be attributed to the large content of carboxyl groups in SA and CMC, and holes and open pores in electrodes. SEM and TEM images showed that E-SA and E-CMC/PTFE had a homogeneous coverage of AB on LFP, which is the key factor for an excellent conductive network and electrochemical performance. We believe that the environmentally friendly water-based binders have broad prospects for use in LIB cathodes. [ABSTRACT FROM AUTHOR]

Nitrogen self-doped mesoporous carbon is synthesized from a novel polybenzoxazine and used as an electrode for supercapacitor applications. Two different types of carbon are derived from the same polybenzoxazine, which is synthesized from apigenin, furfuryl amine, and formaldehyde. Carbon derived from calcination is denoted as APFC-N and the other carbon type derived from an aerogel is denoted as APFC-G. The surface areas of APFC-N and APFC-G are found to be 248 and 635 m2 g−1, respectively. The pore size of APFC-G carbon is in the range of 2–5 nm, which is a suitable pore size for use as an electrode in electrochemical applications. The electrochemical properties of carbon obtained from the aerogel method (APFC-G) show good performance for supercapacitor applications with a specific capacitance of 120 F g−1 at a current density of 0.5 A g−1. At a low voltage scanning rate of <50 mV s−1, a better rectangular shape is observed in the cyclic voltammogram of APFC-G. The impedance spectra of both carbon types agree well with the results of capacitance and the cyclic voltammogram analyses. Also, good cycling stability is retained, even after 25 000 continuous charge–discharge cycles. [ABSTRACT FROM AUTHOR]

In view of the problems surrounding the research and application of carbon materials, the process of choosing a carbon source is still not perfect. There are few studies concentrating on the establishment of structure–property relationships based on the choice of carbon source. In this regard, our present work contributes the design of an organic precursor that is expected to allow the controllable construction of the carbon material, thus regulating its functionality. A highly π-conjugated Schiff base moiety with alternating imine groups (C＝N) and benzene rings was incorporated into the main chain of a mesoporous polymer. For comparison, a bisphenol-A-type moiety was employed in the main chain of another mesoporous polymer. Using the mesoporous polymers as organic precursors for porous carbon sources, the formation of mesoporous carbon can be attributed to the presence of the highly π-conjugated Schiff base moiety due to its self-supporting effect and char-forming ability, which are absent in the bisphenol-A-type moiety. However, we are not only concerned with the contribution from the chemical structure of the designed precursor to the controllable construction of mesoporous carbon, but also concerned with its regulation of the electrochemical performance of the resulting material. Through characterization using cyclic voltammetry (CV), galvanostatic charge–discharge profiles, and electrochemical impedance spectroscopy (EIS), this kind of mesoporous carbon has been found to have excellent charge storage and transportation abilities and shows potential for application in the electrodes of electrochemical capacitors. [ABSTRACT FROM AUTHOR]

A flexible film electrode composed of sodium carboxymethyl cellulose (CMC), polypyrrole (PPy) and reduced graphene oxide (RGO) was designed by in situ polymerization and vacuum filtration. The obtained film displayed CMC–PPy nanospheres wrapped in an RGO framework, resulting in a free-standing and highly flexible supercapacitor electrode. The incorporation of hydrophilic CMC into the film enhanced the diffusion paths of electrolyte ions and prevented the volume deformation of PPy during the long-term charging/discharging. Furthermore, PPy provided a large pseudocapacitance and RGO endowed the film electrode with prominent flexibility. The remarkable interaction between CMC, PPy and RGO achieved a synergistic effect on the structural stability and electrochemical performance of the film electrode. When the mass ratio of CMC–PPy to RGO was 1 : 1, the highest specific capacitance of the sodium carboxymethyl cellulose–polypyrrol@reduced graphene oxide (S-CPR1 : 1) was 489 mF cm−2 (191 F g−1) with a mass of 2.56 mg cm−2 at a current density of 0.5 mA cm−2. And the area specific capacitance of the S-CPR1 : 1 electrode could remain as 101.6% of the original value after 1000 charge/discharge cycles, which was higher than the polypyrrol@reduced graphene oxide (S-PR) electrode (72.4%) prepared under the same conditions. Besides, the S-CPR1 : 1 electrode exhibited remarkable flexibility with 95.6% capacity retention after 500 fold cycles. These above results indicated that the S-CPR1 : 1 film electrode provided a simple way of developing free-standing and flexible electrode materials for next-generation electrochemical electrodes. [ABSTRACT FROM AUTHOR]

The traditional methods of preparing cathode materials usually require long time consuming and high temperature annealing, which consume a lot of material and financial resources. Herein, we report an ultrafast self-propagating combustion process to prepare a sponge-like NaFe2PO4(SO4)2@reduced graphene oxide (NFPS@rGO) material with favorable surface characteristics. This product is successfully prepared in a short time and is well coated with reduced graphene oxide due to its loose porous surface structure. Benefiting from the carbon coating, NFPS@rGO demonstrates an enhanced rate and cyclic performance than that of the pristine NFPS. The discharge specific capacity of NFPS@rGO still retains 43.4 mA h g−1 at a high current density of 500 mA g−1. After 100 cycles at 50 mA g−1, the capacity retention of NFPS@rGO is 83.3%, which is also higher than NFPS by 34.7%. In addition, the fabricated hard carbon‖NFPS@rGO full-cell exhibits a favorable rate and cyclic performance. This study provides meaningful guidance for the modification of cathode materials for sodium-ion batteries and promotes its practical possibility. [ABSTRACT FROM AUTHOR]

With the continuous development and progress of new energy electric vehicles, high-capacity nickel-rich layered oxides are widely used in lithium-ion battery cathode materials, and their cycle performance and safety performance have also attracted more and more attention. In this experiment, a single crystal LiNi0.83Co0.12Mn0.05O2 cathode material was synthesized by co-precipitation and high-temperature solid-phase methods, and its crystal structure, morphology, composition, element distribution and electrochemical performance were systematically studied. The results show that the synthesized single crystal particles have good morphology, uniform element distribution, low Li+/Ni2+ ion mixing degree, and well-developed layered structure. Under the test conditions of 25 °C and 2.75–4.30 V, the first discharge specific capacity of a button cell at 0.1C(1C = 210 mA g−1) reaches 209.7 mA h g−1, the coulomb efficiency is 91.19%, and the capacity retention is 100.90% after 100 cycles at a rate of 0.2C. It should be noted that the capacity retention of the soft package battery is 88.72% after 500 cycles at a rate of 0.3C. Such excellent performance may be because, compared with polycrystalline materials, the smooth micron-sized single crystal particles effectively reduce the electrode/electrolyte interface reaction, volume change and irreversible phase change caused by charging and discharging. [ABSTRACT FROM AUTHOR]

A high-performance electrochemical sensing platform based on CuS nano-globules is efficiently developed. The CuS nano-globules are synthesized through a hydrothermal process. All the important physical characteristics of the nanomaterial such as crystal architecture, morphology, topography and composition are investigated. To better demonstrate the electrochemical sensing capability of CuS nano-globules reinforced electrodes, hydroquinone (HQE) is chosen as an analyte. Upon the electrochemical investigation, the CuS-based sensor displayed an enhanced detection limit of 0.135 μM with a linear range of 1–2287 μM. The overall sensing performance of CuS nano-globules-equipped electrode towards HQE is very impressive with good stability and reproducibility. These investigative results evidently indicate the superior electrochemical properties of CuS nano-globules and they can be highly recommended for real-time analysis. [ABSTRACT FROM AUTHOR]

A series of lanthanum-doped Na3V2−xLax(PO4)3/C (0 ≤ x ≤ 0.03) composites have been fabricated via a simple sol–gel approach. The influences of La3+ substitution on the structure, morphology and electrochemical properties are systematically studied. Rietveld refinement is applied to explore the actual substitution site of La, which proves that La3+ ions successfully occupy the octahedral V sites. It is suggested that appropriate La doping will reduce the particle size and enhance the reversible capacity and rate capability. Among all the samples, the as-prepared Na3V1.99La0.01(PO4)3/C compound shows the highest electrochemical capability. It delivers a high initial specific capacity of 111.3 mA h g−1 at 0.2C and maintains a capacity of 108.1 mA h g−1 over 100 cycles, exhibiting much better electrochemical performance than the original Na3V2(PO4)3/C. In addition, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) experiments suggest that low-level La doping can greatly decrease the polarization and increase electrical conductivity with fast reaction kinetics and a higher Na+ diffusion coefficient. The study presented here will provide considerable insights into rare earth element-doping tactics, which will facilitate the commercialization of sodium-ion batteries. [ABSTRACT FROM AUTHOR]

In this work, a polypyrrole (PPy)–graphene oxide (GO) composite film was electrodeposited on the composite ceramic carbon electrode (CCE) from a solution containing only pyrrole and GO. After further electrochemical reduction and oxidation, a three-dimensional over-oxidized polypyrrole–reduced graphene oxide composite film-modified electrode (3D-OPPy/ERGO/CCE) was obtained. The surface morphology and the electrochemical properties of the modified electrode were studied carefully. This modified electrode was used for the simultaneous determination of dihydroxybenzene isomers with excellent analytical performance due to the good selectivity of OPPy, high electrochemical activity of ERGO, and good permeability of the three-dimensional porous structure of the composite film. Under the optimum conditions, the linear ranges for the simultaneous determination of hydroquinone (HQ), catechol (CC) and resorcinol (RS) by differential pulse voltammetry (DPV) in phosphate buffer (pH 6.0) were 0.50–100 μM (HQ), 0.50–200 μM (CC) and 2.00–200 μM (RS), with the detection limits (at an SNR of 3) of 0.1 μM (HQ and CC) and 0.7 μM (RS), respectively. This modified electrode was used for the determination of dihydroxybenzene isomers in local river water with satisfactory results. [ABSTRACT FROM AUTHOR]

In this study, Co/Ni-MOF-74-derived CoNi2S4 nanoparticles embedded in porous carbon (CoNi2S4@C) were successfully prepared using Co/Ni-MOF-74 as precursor. According to the SEM and TEM images, the CoNi2S4 nanoparticles with a diameter of about 8 nm were uniformly distributed in the composite. Compared to the pure CoNi2S4, CoNi2S4@C exhibits excellent electrochemical performance as an anode material for sodium ion batteries (SIBs). After 50 cycles (at 100 mA g−1), the specific capacity of CoNi2S4@C could be maintained at 438 mA h g−1. After the CoNi2S4@C electrode was charged/discharged at different current densities of 50, 100, 200, 500, 800, 1000, and 2000 mA g−1, the specific capacity returned to the original level when the current density was restored to 50 mA g−1. This is due to the fact that the composite material can reduce the effect of volume expansion. [ABSTRACT FROM AUTHOR]

A practical strategy to enhance the electrochemical performance of Li-rich and Mn-based Li1.38Ni0.25Mn0.75O2.38 has been introduced. Its micromorphology and microstructure are controlled during the preparation process. Powder X-ray diffraction (XRD) and Raman spectroscopy reveal that the as-obtained materials can be indexed as the α-NaFeO2 phase. Field emission scanning electron microscopy (FESEM) analyses demonstrate that the as-fabricated Li1.38Ni0.25Mn0.75O2.38 materials consist of 10–15 μm spherical secondary particles aggregating with spherical nanoscale primary particles, and the primary particle size and stacking faults can be controlled by altering the calcination temperature. The electrochemical measurements show that Li1.38Ni0.25Mn0.75O2.38 with nanoscale primary particles with the diameter of 100–200 nm and an appropriate amount of stacking faults obtained at 850 °C exhibits higher capacity and superior cycling performance, delivering an initial discharge capacity of 265.7 mA h g−1 at 0.1C, 243.1 mA h g−1 at 0.2C, 222 mA h g−1 at 1.0C and 169 mA h g−1 at 2.0C, accompanied with a capacity retention of 89.3% and 78.6% after 300 cycles and 500 cycles at 1.0C, respectively. Meanwhile, the XPS, EIS and TEM results of the electrodes indicate that the capacity fading in the first 50 cycles may be caused by interfacial side-reactions between electrode and electrolyte. [ABSTRACT FROM AUTHOR]

Building a novel electrode with improved electrochemical behaviour has great scope in the area of supercapacitors. In this work, binder-free 1D nanograsses of Ni2P2O7/Co2P2O7 nanocomposites were grown on nickel foam through a simple hydrothermal method at different processing temperatures. A precise examination was carried out to study the influence of the processing temperature on the morphology and electrochemical attributes. Ex situ morphological pictures confirmed the reliance of structure on the hydrothermal temperature and the obtained one-dimensional morphology encouraged ion interaction through short channels. The patterned nanograsses were grown at 140 °C with uniform interspacing and exhibited better electrochemical performance due to short, diffusive 1D pathways. Using the power law, the capacitive parts of the total capacitance were elucidated. The better electrochemical performance from charge–discharge indicates that the binder-free NiP2O7/CoP2O7 1D nanograsses would be an appropriate cathode for an efficient hybrid capacitor. The optimized electrode as the cathode in the device showed better energy density and long-lasting cycle life (80% capacity retention after 2000 cycles). Our outcomes indicate that the Ni2P2O7/Co2P2O7 1D nanograss pattern has good potential for use as a cathode for hybrid supercapacitors. [ABSTRACT FROM AUTHOR]

An efficient way to enhance the energy density of a supercapacitor device is to improve the electrochemical activity of the anode and cathode materials. The electrochemical performance of the NiCo2O4 metal oxide is enhanced by assembling a composite with Mn2O3. Herein, a Mn2O3/NiCo2O4 composite material was synthesized via a one-step in situ hydrothermal method, and the electrochemical and electrocatalytic behaviours were studied. The Mn2O3/NiCo2O4 battery-type electrode material exhibited a maximum specific capacity value of 824 C g−1 at a current density of 1 A g−1 and a superior cyclic stability (85%), making it a suitable anode material for supercapacitor application. A Mn2O3/NiCo2O4//AC asymmetric device exhibited maximum energy density and power density values of 48.6 W h kg−1 and 6.4 kW kg−1, respectively. The superior electrochemical performance of the Mn2O3/NiCo2O4 composite material inspired us to apply it as an electrocatalyst for glucose sensing. The limit of glucose detection and the linear range of the Mn2O3/NiCo2O4 electrocatalytic material were 35 μM and 0.01–15 mM, respectively. [ABSTRACT FROM AUTHOR]

Fentanyl is a potent, effective analgesic and narcotic drug widely used for anesthesia and chronic pain control. In this study, a simple electrochemical method for the detection of fentanyl in aqueous solutions was developed. The modification of a screen-printed carbon electrode (SPCE) was performed by casting a metal–organic framework (MOF) on its surface. The characterization of the zinc-based MOF (Zn(II)-MOF) modifier was investigated via scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) techniques. The differential pulse voltammetry (DPV) technique was used for evaluating the fentanyl electrochemical behavior on the electrodes. The optimum experimental conditions were investigated by examining the effects of the scan rate and pH on the cyclic voltammetry (CV) and DPV responses, respectively. The results showed that fentanyl has an irreversible behavior at the potential of 0.9 V and its current increases in the presence of MOF. The application of the presented electrode with the DPV method showed a detection limit of 0.3 μM in the concentration range of 1–100 μM (linear range) for the fentanyl in an aqueous solution. The modified electrode was successfully used to determine the low levels of fentanyl in urine and plasma as the real samples. [ABSTRACT FROM AUTHOR]

The ongoing demand for supercapacitors with high energy density, stability, and a wide range of working potential for device applications is a great challenge to researchers. In this study, we have explored suitability of nanocomposites based on functionalized BNs (mK-BN/mH-BN), CNTs, and polyaniline (PANI) as supercapacitor electrodes to address this demanding issue. We have also focused on the enhancement of the electrochemical activity of BN with surface functionalization. FTIR and XPS analysis confirmed successful incorporation of oxygen functionality on the BN surface. Morphological analysis indicated exfoliation of BN after modification and homogeneous growth of PANI-coated CNTs on exfoliated modified BN. Among the ternary nanohybrids, the mK-BN/CNT/PANI composite achieved highest specific capacitance of 515 F g−1 and an energy density of 46 W h kg−1 in a three-electrode system. Furthermore, cyclic stability of mK-BN/CNT/PANI is found to be ∼98% after the completion of 10 000 charging–discharging cycles. For device application, the mK-BN/CNT/PANI based asymmetric supercapacitor showed efficient electrochemical activity with an enhanced energy density of 62 W h kg−1 and capacitance retention of ∼91% after 5000 cycles. The comparative electrochemical efficiency of the electrode material has also been examined in two different organic electrolytes. All these excellent electrochemical characteristics demonstrated the high potentiality of mK-BN/CNT/PANI for real-time supercapacitor applications. [ABSTRACT FROM AUTHOR]

In order to improve the specific capacity and cyclability of the iron phosphide (FeP) anode material, mesoporous iron phosphide/reduced graphene oxide (FeP/RGO) nanocomposites were synthesized by a simple precipitation reaction process and low temperature phosphorization technology. FeP nanoparticles with a diameter of about 10–15 nm were uniformly loaded on hierarchical RGO nanosheets. When used as the anode for sodium ion batteries, the FeP/RGO nanocomposite electrode exhibits a high reversible specific capacity of about 547 mA h g−1 at a current density of 100 mA g−1 after 100 cycles. A stable long cycling capacity of about 311 mA h g−1 can also be obtained at a high current density of 1 A g−1 after 1000 cycles. The synergistic interaction between FeP nanoparticles and RGO improved the electrochemical performance of the electrode materials greatly. The outstanding sodium ion storage performance of the FeP/RGO nanohybrid electrode can be attributed to the hierarchically porous structure, good electrical conductivity, and small size effect of the nanoparticles. [ABSTRACT FROM AUTHOR]

In this work, BaLi2Ti6O14 nanofibers coated by a thin carbon layer were rationally designed and synthesized by a controlled electrospinning process and a simple annealing process. The carbon content of the composite is as low as 1.91 wt%. This thin carbon layer is considered to contribute to remarkably improving the rate capability. Furthermore, BaLi2Ti6O14@C nanofibers can deliver a high reversible capacity of 95.0 mA h g−1 with a capacity retention of 83.4% at a high current density of 1000 mA g−1 after 800 cycles. Analysis of the electrochemical results showed that the existence of the carbon coating layer plays a positive role in improving the structural stability and ionic transport of BaLi2Ti6O14 during the charge/discharge processes, thereby indicating a general method for improving the electrochemical performance of electrode materials with poor electrical conductivity. [ABSTRACT FROM AUTHOR]