Electrochemical Capability Research Articles

Research status and prospect of electrode materials for lithium-ion battery

The lithium-ion battery has become one of the most widely used green energy sources, and the materials used in its electrodes have become a research hotspot. There are many different types of electrode materials, and negative electrode materials have developed to a higher level of perfection and maturity than positive electrode materials. Enhancing the electrochemical capabilities of positive electrode materials is therefore crucial. In addition to exploring and choosing the preparation or modification methods of various materials, this study describes the positive and negative electrode materials of lithium-ion batteries. Among the negative electrode materials, Li4Ti5O12 is beneficial to maintain the stability of the battery structure, and the chemical vapor deposition method is the best way to prepare nitrogen-doped graphene materials. Doping and coating modifications for positive electrode materials can offer a smoother mobile route for lithium ions, which can enhance the cathode materials cycling performance. This papers study, summary, and outlook on electrode materials for lithium-ion batteries can aid those researchers in developing a more thorough understanding of electrode materials. Also, it can be advantageous for the growth of associated follow-up research projects and the expansion of the lithium battery market.

Laser Thermal Shock Enabling Ultrafast Spin Regulation of MnO2 for Robust Pseudocapacitive Energy Storage

AbstractThe pseudocapacitive performance of MnO2 is intrinsically determined by its electronic structure, especially the spin state. However, the correlation between the electrochemical behavior and the spin state of electrode materials remains ill‐defined, and efficient spin regulation strategies for MnO2 are thus lacking. Herein, the study reports laser thermal shock of electrochemically deposited MnO2 for efficient spin regulation. The combined use of theoretical calculation and experimental investigation indicates that the thermal shock induces oxygen vacancy in MnO2 to reduce spin polarization and delocalize electron distribution. As a result, the electrical conductivity largely increases and the Na+ adsorption is reasonably optimized. By lasering an integrated electrode for only 83 s, a 54% increase of the specific capacitance is observed. For the first time, the pseudocapacitive capability of MnO2 is revealed by in situ electron paramagnetic resonance where the enhanced redox pair is correlated with evolution of Mn2+ during charge/discharge. Moreover, the commercial‐level mass‐loaded electrode also offers a decent performance enhancement after laser treatment, indicating the great prospect of this technology for real applications. This work innovatively correlates the pseudocapacitive performance of MnO2 with its spin state and offers a new avenue to optimize the electrochemical capability through spin regulation.

Practical mechanochemical synthesis and electrochemical properties of Mn3O4 for use in supercapacitors

A facile method to synthesize Mn3O4 crystalline powders for use in supercapacitor electrodes is reported. Specifically, the mechanochemical synthesis was carried out with high-energy ball milling and a short milling time of 1 h. The physicochemical properties of the resultant powders were characterized by XRD, Raman spectroscopy, SEM, and N2 adsorption-desorption techniques. In addition, the electrochemical capabilities were tested in two different configurations: a three-electrode cell, and a symmetric supercapacitor (SSC) with a two-electrode arrangement. Cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge were applied to the samples with both configurations. The Mn3O4 samples were synthesized from manganese chloride tetrahydrate and sodium peroxide with two molar ratios, 1:1 and 1:1.5. The samples showed excellent electrochemical stabilities of 99.7 % after 5000 charge-discharge cycles, and the highest electrochemical capacitance of 485 F·g1 at 5 mV s1 was observed for the sample prepared with a 1:1 ratio of reagents and used with the three-electrode configuration.

Self-healing electrical bioadhesive interface for electrophysiology recording

Electrical bioadhesive interfaces (EBIs) are standing out in various applications, including medical diagnostics, prosthetic devices, rehabilitation, and human–machine interactions. Nonetheless, crafting a reliable and advanced EBI with comprehensive properties spanning electrochemical, electrical, mechanical, and self-healing capabilities remains a formidable challenge. Herein, we develop a self-healing EBI by thoughtfully integrating conducting polymer nanofibers and a typical bioadhesive within a robust hydrogel matrix. The accomplished EBI demonstrates extraordinary adhesion (lap shear strength of 197 kPa), exceptional electrical conductivity (2.18 S m−1), and outstanding self-healing performance. Taking advantage of these attributes, we integrated the EBI into flexible skin electrodes for surface electromyography (sEMG) signal recording from forearm muscles. The engineered skin electrodes exhibit robust adhesion to the skin even when sweating, rapid self-healing from damage, and seamless real-time signal recording with a higher signal-to-noise ratio (39 dB). Our EBI, along with its skin electrodes, offers a promising platform for tissue-device integration, health monitoring, and an array of bioelectronic applications.

Multifunctional enhanced energy density integrated supercapacitor based on self-healing redox-mediated gel polymer electrolyte

Flexible supercapacitors have undergone rapid development, however, there is still a serious challenge in integrating multiple functions into a single supercapacitor. Therefore, higher requirements are put forward for electrolytes and assembled technology. Herein, a redox-mediated physically crosslinked double network polyacrylic acid/polyisodecyl methacrylate/K3[Fe(CN)6] gel polymer electrolyte (GPE) has been synthesized. The double network structure and reversible interactions, including hydrophobic association, hydrogen bond and ion coordination, endow the GPE with exceptional strength, toughness and self-healability. In particular, Fe2+/Fe3+ ions play a dual role as charge carriers and crosslinking agents, simultaneously increasing the electrochemical and mechanical capabilities of the GPE (3.76 S/m and 1.99 MPa, respectively). Subsequently, a flexible integrated supercapacitor has been developed through in situ polymerization of aniline on the surface of GPE. Thanks to the seamless construction and reversible redox reactions of Fe2+/Fe3+, the supercapacitor exhibits significantly enhanced capacitance and energy density (271.6 mF/cm2 and 98.1 μWh/cm2, respectively). Moreover, the supercapacitor demonstrates promising self-healability with a 99.3 % capacitance retention rate after 10 cutting/healing cycles. Due to the mutual fusion of the electrode and electrolyte layers, the outstanding electrochemical durability is obtained even under severe deformations. Overall, the redox-mediated double network GPE and the unique integrated configuration provide an effective strategy for multifunctional energy storage devices.

Porous metal-organic frameworks derived carbon and nickel sulfides composite electrode for energy storage materials

Researchers have extensively investigated the use of metal-organic frameworks (MOFs), which contain a greater surface area, high porosity, and controlled pore structure, in supercapacitors, sensors and biological applications. Here, we present a novel method for the sonication-improved hydrothermal reaction process of nickel sulfides decorated on metal organic framework derived carbon composite. The NiS@Ni-MOF composite has improved surface, morphological, and electrochemical properties after being annealed at an ideal temperature of 200 °C and then being subjected to a hydrothermal process. The composite electrode fabrication displays improved specific capacitances of 950 F/g at 1 A/g, long-lasting cycle stability, and exceptional capacitance retention in the presence of 6 M KOH electrolyte. Additionally, even at a high current density of 5 A g−1 and 5000 cycles, the capacitance retention can keep 99.7 % of its original value. The NiS@Ni-MOF composite's synergistic effects between its distinctive structural features are responsible for its superior electrochemical capabilities, which make it a promising electrode material for high performance supercapacitors.

The electrochemical kinetics of chloride oxidation over multi-metallic Pt-Ni-Co electrodes affected by metal deposition method and electrode support

Platinum, nickel, and cobalt oxides were coated on different electrode supports (graphite, stainless steel mesh, Ti foil and Ni form) by multistep electrode deposition method. Scanning electron microscopy, X-Ray diffraction, X-ray photoelectron spectroscopy, cyclic voltammetry and linear sweep voltammetry were used to characterize electrodes. Results showed that the deposition process, such as applied current and deposition time, and the substrates influenced electrode morphology and electrochemical chlorine generation capability. Porous structure and Co3O4 crystalline could promote chloride oxidation on electrode surface. Graphite substrate exhibited the benefit of chloride oxidation and 0.6A × 20 s× 30 is the optimal deposition condition for electrode fabrication. The 0.6A × 20 s× 30-G electrode has the lowest chlorine evolution potential, largest difference in water oxidation and chloride oxidation potential, and the smallest transfer coefficient (α), meaning that this electrode is more favorable to chloride oxidation than other electrodes. Moreover, a mechanism of chlorine generation has been proposed in this study, indicating that chlorine radicals were formed on electrode surface. The high chlorine generation capability and good durability of Pt-Ni-Co-G electrode has the potential for application in water treatment process, such as disinfection and inorganic or organic pollutants decontamination.

Tailoring ligand fields of metal-azolate frameworks for highly selective electroreduction of CO2 to hydrocarbons at industrial current density

The catalytic activity of a metal complex is often contingent upon factors such as its valence state, coordination configuration of the metal ion, and coordination ability of the ligand. Hence, revealing the influence of the ligand field of the active metal center on the selectivity of the product for electrochemical CO2 reduction is crucial. Herein, three isostructural metal-azolate frameworks (MAFs) (Cu-BTP, Cu-BTTri, and Cu-BTT) with the same cyclic tetracopper(II) cluster units, namely [Cu3(BTP)2] (Cu-BTP, H3BTP = 1,3,5-tris(1H-pyrazol-4-yl)benzene), [Cu3(BTTri)2] (Cu-BTTri, H3BTTri = 1,3,5-tris(1H-1,2,3-triazol-5-yl)benzene), and [Cu3(BTT)2] (Cu-BTT, H3BTT = 1,3,5-tris(2H-tetrazol-5-yl)benzene) were synthesized using pyrazolate-, triazolate-, and tetrazolate-based ligands, respectively. The synthesized MAFs were subjected to analysis to evaluate their electrochemical capabilities for reducing CO2 under identical reaction conditions. Among them, the pyrazolate MAF, Cu-BTP, delivers a current density of 1.25 A cm2 in a flow cell device with the highest Faradiac efficiency for hydrocarbons (CH4, 60%; C2H4, 22%). Furthermore, the system shows no obvious degradation over 60 h of continuous operation. The order of selectivity of the three MAFs for hydrocarbon production is consistent with the corresponding pKa values of the azolate ligands. Theoretical calculations show that a stronger Lewis basicity of the organic ligand, resulting in a stronger ligand field strength, is conducive to strengthening the binding of metal centers with key intermediates, such as *CO and *CHO. This ultimately leads to the deep reduction of CO2 to hydrocarbons.

Fabrication of an Electrochemical Sensor Based on a Molecularly Imprinted Polymer for the Highly Sensitive and Selective Determination of the Antiretroviral Drug Zidovudine in Biological Samples.

Molecularly Imprinted Polymers (MIP) have demonstrated considerable potential when combined with electrochemical sensors, exhibiting high sensitivity, selectivity and reproducibility levels. The aim of this work is to detect Zivudine (ZDV) in serum samples by means of an interface imprinting technique-based electrochemical sensor. Thus, ZDV was used as a template for the creation of an MIP-based electrochemical sensor, and differential pulse voltammetry (DPV) was used as the determination technique for the molecule. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques were also used to characterize the electrochemical sensor capabilities, which showed a good linearity between 1.0 × 10-10 M and 1.0 × 10-9 M. ZDV was detected with a detection limit of 1.63 × 10-11 M, while the recovery analysis of spiked serum samples demonstrated that the sensor was highly selective.

Exceptional Lithium‐Ion Storage Performance on an Azo‐Bridged Covalent Heptazine Framework

AbstractGraphitic carbon nitride (g‐C3N4) possesses rich pyridine nitrogens, which is helpful for facilitating electrochemical capability in Li+ storage; however, its poor conductivity is still the main challenge. Based on the knowledge of its intrinsic merits and defects, here, it is proposed to integrate active heptazine (HEP) species with functional linkers into orderly molecular structures for improved performance. As the first proof‐of‐concept, a unique azo‐linked covalent heptazine framework (Azo‐CHF) where two HEP units are bridged with azo linkages, is ingeniously designed and prepared to enhance the inherent charge conductivity for Li+ storage. Attributing to the deeply extended conjugation along overlapping azo nitrogens and the aromatic π system of HEP cores, Azo‐CHF with the lowest bandgap (2.58 eV) exhibits enhanced Li+/e− transport than g‐C3N4 through density functional theory calculations. Therefore, the Azo‐CHF anode exhibits an unprecedented performance with a large reversible capacity (1723.0 mAh g−1 at 0.1 A g−1), superior rate capability (824.0 mAh g−1 at 10 A g−1), and impressive cyclability (756.5 mAh g−1 undergoing 1000 cycles at 10 A g−1). This study not only demonstrates the great application prospect of Azo‐CHF for Li+ storage, but also opens a fantastic window to further explore high‐performance electrodes by integrating HEP with other active motifs.

Novel O, P, S self-doped with 3D hierarchy porous carbon from aromatic agricultural waste via H3PO4 activation for supercapacitor electrodes

Rapid progress in energy storage technology, specifically concerning supercapacitors as an extension of conventional capacitors and batteries, is increasingly becoming a focal point of attention. Supercapacitor electrode components can be designed using diverse range of advantageous conductive materials. Creation of electrodes involved the conversion aromatic biomass (AB) into porous activated carbon (AC), which possessed pore structure and composition that enhanced its practical utility. AB raw waste is prepared by drying material and precarbonizing. AB carbons were chemically activated 0.5 M (H3PO4, KOH, NaOH) by pyrolysis (N2-CO2) from 30 to 850 °C. Based on physical characteristics, AB-H3PO4 is confirmed as the best condition confirmed advantageous pore structure 3D hierarchical which can be accessed by electrolyte ions during electrochemical processes. However, AB-H3PO4 showed remarkable electrochemical capabilities, exhibiting Csp = 293.73 F g−1, Esp = 39.21 Wh kg−1, and Psp = 134.86 W kg−1 at current density 1 A g−1. These results were attributed to the specific capacitance of the oxidation-reduction reaction, triple self-doping heteroatoms O, P, S with carbon purity 88.69 %. Suitability chemical activators with AC based on AB waste influenced the creation of pore structures. These structures optimized accessibility for electrolyte ions, while availability of heteroatoms contributed to high specific capacitance. The factors collectively impacted application of supercapacitor electrode components.

Surface Ligand Modification on Ultrathin Ni(OH)2 Nanosheets Enabling Enhanced Alkaline Ethanol Oxidation Kinetics.

The ethanol oxidation reaction (EOR) is an economical pathway in many electrochemical systems for clean energy, such as ethanol fuel cells and the anodic reaction in hydrogen generation. Noble metals, such as platinum, are benchmark catalysts for EOR owing to their superb electrochemical capability. To improve sustainability and product selectivity, nickel (Ni)-based electrocatalysts are considered promising alternatives to noble-metal EOR. Although Ni-based electrocatalysts are relieved from intermediate poisoning, their performances are largely limited by their relatively high onset potential. Therefore, the EOR usually competes with the oxygen evolution reaction (OER) at working potentials, resulting in a low EOR efficiency. Here, we demonstrate a strategy to modify the surface ligands on ultrathin Ni(OH)2 nanosheets, which substantially improved their catalytic properties for the alkaline EOR. Chemisorbed octadecylamine ligands could create an alcoholophilic layer at the nanosheet surface to promote alcohol diffusion and adsorption, resulting in outstanding EOR activity and selectivity over the OER at higher potential. These non-noble-metal-based 2D electrocatalysts and surface ligand engineering showcase a promising strategy for achieving high-efficiency electrocatalysis of EOR in many practical electrochemical processes.

Examining Electrochemical and Mechanical Behavior of Amorphous and Crystalline Sulfide-Based Solid-State Electrolytes

Traditional liquid electrolytes used in lithium-metal batteries have severe safety issues, poor power density, as well as thermal and electrochemical instability that prevent scaling to newer applications, such as electric vehicles. Sulfide-based solid-state electrolytes (SSEs) are viable for addressing many of the issues seen with liquid electrolytes. However, one of the key hindrances to the use of sulfide-based SSEs is the understanding of repeatable processing of highly conductive, stable material. There are limitations in producing electrolyte with known defect types and density, as well as degree of crystallinity. The degree of crystallinity greatly effects electrochemical properties, such as ionic conductivity, due to the change in ionic pathways through the electrolyte. However, other hindrances to SSE capabilities, such as interfacial stability and mechanical integrity, are not noted as a function of crystallinity. Here, multiple forms of characterization were utilized to confirm structural information on dry ball milled Li7P3S11 (LPS) SSEs. A range of crystallinity of pelletized electrolytes were then analyzed with different electrochemical and mechanical tests to evaluate the viability of SSEs in operation. There is particular interest in the near-amorphous regime of crystallinity, where minimal differences are seen in electrochemical capabilities, though there is uncertainty in the possible benefits observed for interfacial compatibility and in mechanical properties. Electrochemical impedance spectroscopy (EIS) and symmetric cell cycling were utilized to examine the bulk and interfacial capabilities of electrolytes, all operated under various loads with a specialty designed load cell. Mechanical properties were analyzed with mechanical testing on different scales, from bulk loading down to atomic force microscopy mapping and nanoindentation testing. With this wide array of characterizations, a wholistic understanding of slightly varied crystallinity of sulfide-based SSE is accomplished.

Influence of surface roughness on the anticorrosion performance of plasma sprayed amorphous coating and its electrochemical evaluation

In this current survey, the association relating surface roughness to electrochemical corrosion capability of plasma sprayed Fe48Cr15Mo14C15B6Y2 amorphous coating was examined. The impact of semiconducting performance, compositional variation and point defects diffusivity on the electrochemical anti-corrosion behavior was also evaluated. In case of chloride-containing electrolyte, a rougher surface of the coating degraded the passivity and anti-corrosion capacity of passive film. The increase of hydroxyl vacancies contributed to a more defective passive film accompanied by a greater donor density for the coating with a rougher surface. Moreover, a reduction in Mo elemental species was not conductive to a continual growth of insoluble oxide Cr2O3, which was found as the dominant factor decreasing the resistance to corrosion of the generated film. A higher diffusivity of point defects existent in the generated layer owing to a rougher surface led to a more rapid mass transfer process.

Sonochemically produced ternary metallic sulfides to enhance the electrochemical performance of asymmetric supercapacitors

Designing compositions of transition metal alloys alongside their nanostructures remains pivotal in the creation of electrochemical energy storage devices. Supercapacitors, renowned for their remarkable electrochemical capabilities, have garnered substantial interest. Nonetheless, there persists a need for electrode materials exhibiting enhanced charge storage characteristics. In this respect, the simple sonochemical method was used to easily synthesize various magnesium, silver, and copper sulfide composites. In a three-electrode setup, the electrode material Mg25Ag50Cu25S (MACS) exhibits outstanding electrochemical properties. MACS enabled the attainment of an outstanding specific capacity of 825 C/g at 1.0 A/g, showcasing its remarkable performance in this regard. Asymmetric supercapacitors were also made with the MACS. This assembly allowed the charge-storing ability to be further examined in two electrode setup. The MACS//AC device showed an outstanding energy density of 45 Wh/kg having an 850 W/kg power density thus demonstrating exceptional energy-storing ability. Cyclic stability of 73% after 5000 GCD cycles was also shown by this MACS//AC device. The developed ternary metal sulfides exhibit outstanding properties when assessed against previously published literature, offering an effective and preferred component in future storage technologies.

Helical fluorinated carbon nanotubes/iron(iii) fluoride hybrid with multilevel transportation channels and rich active sites for lithium/fluorinated carbon primary battery

Abstract Lithium/fluorinated carbon (Li/CF x ) primary battery is a promising energy supply device with high energy density. However, poor electrochemical capabilities such as the initial voltage delay phenomenon and the large polarization have obstructed their applications. The electrochemical performance of CF x primarily depends on the feature of the carbon source and the corresponding fluorination technique. Herein, we developed a high energy density Li/CF x battery by employing helical carbon nanotubes (HCNTs) as the carbon source. In detail, the precise control of the fluorination temperature was designed at the range of 250–400°C to tune the F/C ratio of CF x . Furthermore, the high F/C ratio of fluorinated HCNTs (F-HCNTs) reaches about 1.43, which surpasses the highest theoretical value in fluorinated crystalline carbon materials. Due to the active rich fluorination sites provided by the periodical insertion of the carbon pentacyclic (C5) and heptacyclic (C7) rings, HCNTs exhibited a defect-rich feature and F-HCNTs have a nodular shape. These features favor to enhance the transport of lithium ions and allow more C–F bonds to react with lithium ions, leading to a high energy density of 2133.13 W h/kg. This novel material offers an alternative approach for lithium primary battery being great potential in actual applications.

Exploring the potential of hydrothermally synthesized AgZnS@Polyaniline composites as electrode material for high-performance supercapattery device

Polyaniline (PANI), being one of the highly stable and electroactive conducting polymers, is under investigation for some past years for its better conductivity and other electrochemical characteristics. In this research, PANI is utilized to enhance the electrochemical capabilities of silver-zinc sulfide (AgZnS). The synthesis of silver-zinc sulfide was done hydrothermally, while PANI was prepared via polymerization of aniline. The improvement in capabilities of silver-zinc sulfide was analyzed by adding PANI in it in 25%, 50%, and 75% weight ratios. One of the compositions with 50% PANI unveiled an excellent specific capacity (Qs) of 1121.6 Cg−1. The same composition was further examined for its charge storage capability by assembling a supercapattery device. The assembled device functioned remarkably well resulting in a highest Qs value of 223.44 Cg−1 at 1 Ag−1. Moreover, the device delivered a tremendous energy density of 49.65 Wh kg−1 at a power density of 795.33 W kg−1. The device lost only 10% of its capacity following 5000 charge-discharge cycles, while the Coulombic efficiency remained to be 95% over the same number of cycles at 4.2 Ag−1. The highest power density turned out to be 7678.93 W kg−1 with the lowest energy density of 9.62 Wh kg−1. The reported work, as compared to previous work puts forward a suitable electrode material to be exploited in superior energy storage devices.

Multifunctional Graphene–Polymer Nanocomposite Sensors Formed by One-Step In Situ Shear Exfoliation of Graphite

Graphene nanocomposites are a promising class of advanced materials for sensing applications; yet, their commercialization is hindered due to impurity incorporation during fabrication and high costs. The aim of this work is to prepare graphene–polysulfone (G−PSU) and graphene–polyvinylidene fluoride (G−PVDF) nanocomposites that perform as multifunctional sensors and are formed using a one-step, in situ exfoliation process whereby graphite is exfoliated into graphene nanoflakes (GNFs) directly within the polymer. This low-cost method creates a nanocomposite while avoiding impurity exposure since the raw materials used in the in situ shear exfoliation process are graphite and polymers. The morphology, structure, thermal properties, and flexural properties were determined for G−PSU and G−PVDF nanocomposites, as well as the electromechanical sensor capability during cyclic flexural loading, temperature sensor testing while heating and cooling, and electrochemical sensor capability to detect dopamine while sensing data wirelessly. G−PSU and G−PVDF nanocomposites show superior mechanical characteristics (gauge factor around 27 and significantly enhanced modulus), thermal characteristics (stability up to 500 °C and 170 °C for G−PSU and G−PVDF, respectively), electrical characteristics (0.1 S/m and 1 S/m conductivity for G−PSU and G−PVDF, respectively), and distinguished resonant peaks for wireless sensing (~212 MHz and ~429 MHz). These uniquely formed G−PMC nanocomposites are promising candidates as strain sensors for structural health monitoring, as temperature sensors for use in automobiles and aerospace applications, and as electrochemical sensors for health care and disease diagnostics.

Highly Stable MWCNT@NVP Composite as a Cathode Material for Na-Ion Batteries.

A 3D framework with Nasicon structured polyanionic Na3V2(PO4)3 (NVP) has been emphasized as a leading cathode material for sodium-ion batteries (SIBs) due to its high working voltage plateau, structural stability, and good rate performance. Herein, pristine NVP and MWCNT@NVP composite synthesized via a facile solid-state method are examined and compared as cathode materials for Na-ion batteries. The morphological study confirms the uniform distribution of MWCNTs in the pristine NVP structure. Impedance spectroscopy clearly confirms more diffusion of Na ions for the MWCNT@NVP composite as compared to pristine NVP, considering its diffusion coefficient which directly implies on an increase in specific capacity. MWCNT@NVP (FNV-2) showed specific discharge capacity 110 mAhg-1 at 0.1C current rate which is almost stable at higher current rates with marginal fading. However, the pristine NVP shows capacity loss at a higher current rate. It is noteworthy that the MWCNT@NVP composite shows stable performance with marginal specific capacity fading (1%) compared to pristine (15%). This is because of the mechanical integrity and stability afforded to the composite by the intertwined MWCNT framework in the MWCNT@NVP composite matrix against electrode degradation during the electrochemical reaction. More significantly, even at a higher current rate, that is, at 10 C, the composite recorded a very stable and excellent Columbic efficiency of 97% with a reversible specific capacity of 94 mAhg-1 after 2000 cycles. An enhanced electrochemical performance, that is, rate capability and cycling stability, demonstrates the high potential of the MWCNT@NVP composite for Na-ion storage. Moreover, a sodium-ion full cell with hard carbon demonstrated a reversible capacity of 103 mAhg-1 at C/20 current rate, which clearly demonstrates that MWCNT@NVP is a promising cathode material for sodium-ion batteries.

Synthesis of p-aminothiophenol functionalized graphene oxide/silver nanoparticles nanocomposite and its application for the determination of rutin in rose species flowers

This study used an electrochemical sensor based on a glassy carbon electrode that was designed with a nanocomposite of silver nanoparticles and p-aminothiophenol functionalized graphene oxide (Ag NPs/PATP/f-GO/GCE) to measure the level of rutin in actual samples taken from flowers of rose species. To create the Ag NPs/PATP/f-GO nanocomposite, the Ag NPs were synthesized using the traditional heating process and chemically combined with acid-treated GO and p-aminothiophenol. Ag NPs/PATP/f-GO nanocomposite's effective production was confirmed by X-ray diffraction (XRD), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS) investigations. The construction of a sensitive, selective electrochemical system for the identification of rutin was made possible by the synergistic interaction of Ag NPs, PATP, and f-GO nanosheets, as demonstrated by electrochemical studies based on cyclic voltammetry (CV) and square wave voltammetry (SWV) measurements. The suggested sensor demonstrated a linear response of 5–1050 μM. It was determined that the sensitivity and limit of detection (LOD = 3σ/S, where S is the slope of the regression line and σ is the standard deviation of the intercept) were 0.02902 μA/μM and 17 nM, respectively. For the purpose of determining the level of rutin in a genuine sample made from flowers of a rose species (damascene rose) from Nanyang in Henan province, China, the suggested electrochemical rutin sensor's accuracy and capability were evaluated. Results showed that Ag NPs, PATP, f-GO, GCE may be used as dependable rutin sensors to monitor the rutin concentration in samples of rose species flowers with remarkable recovery values (higher than 98.32 %) and relative adequate accuracy (RSD less than 5.41 %).