In-situ grown hierarchical ZnCo2O4 nanosheets on nickel foam as binder-free anode for lithium ion batteries

Nickle foam-supported hierarchical ZnCo₂O₄ nanosheets was prepared via a facile solution-based method. Porous ZnCo₂O₄ nanosheets were in-situ grown on current collector, forming a binder-free electrode. When evaluated as anode for Lithium ion batteries (LIB_S), the binder-free electrode showed an attractive electrochemical performance. A reversible capacity of 773?mAh?g^?1 could be stably delivered after a 500-cycle test at a current density of 0.25?A?g^?1, with a high capacity retention of 87%. The electrode could maintain a high reversible capacity of 245?mA?h?g^?1 even at an elevated current density of 8.0?A?g^?1. Integrated structure and rich porosity of the binder-free electrode were believed to contribute to the superior performance. Thus, the Nickle foam-supported ZnCo₂O₄ electrode is a promising anode for high performance LIBs in the coming future.     

Structural rearrangement by Ni,Cr doping in zinc cobaltite and its influence on supercapacitance

Transitional metal oxides are prevalent in the energy storage devices due to their remarkable electrochemical activity and charge storage capability. In this study, a spinel structured zinc cobaltite (ZnCo₂O₄) is doped with Ni and Cr to form a novel (Ni,Cr:ZnCo₂O₄) electrode material towards supercapacitor (SC) applications. Dopants served as a conductivity booster, particle size reducer and active sites provider benefitting the electrochemical activity. Comparatively, the doped sample delivered a higher capacitance value of 575 Fg^-1 in the potential range of 0–0.6V with 1 M KOH solution as an electrolyte which is higher than that of the pristine material and better cyclic stability is improved from 82.2% to 90.24% for 2000 cycles. The specific capacitance value of 30 Fg^-1 and 73 Fg^-1 at 0.75 Ag^-1 is achieved for the fabricated asymmetric supercapacitor device with Ni,Cr:ZnCo₂O₄ using Cu foil and Ni foam as current collector respectively. The device assembled with doped sample using Ni foam current collector has an energy density of 16.3 WhKg^?1 and a power density of 0.9 KWKg^?1 superseding the performance of the devices constructed with the pristine ZnCo₂O_4. The performance of Ni and Cr doped spinel structured zinc cobaltite device indicates a notable progress towards the direction of better performance supercapacitor applications.     

Enhanced electrochemical performance of hybrid composite microstructure of CuCo2O4 microflowers-NiO nanosheets on 3D Ni foam as positive electrode for stable hybrid supercapacitors

Self-assembled composite porous structures comprising CuCo₂O₄ microflowers and NiO hexagonal nanosheets were synthesized on a conducting 3D Ni foam surface [CCO/NO] using a simple hydrothermal method. This unique composite assembly was further characterized and electrochemically evaluated as a binder-free positive electrode for hybrid supercapacitor application. The study showed that the CCO/NO exhibited a maximum areal capacitance of 1444 mF cm^?2, significantly higher than the parent CuCo₂O₄ and NiO electrodes, with remarkable stability of 88.5% for 10,000 galvanostatic charge-discharge cycles. Key features for the enhanced electrochemical performance of CCO/NO can be related to a lowered diffusion resistance because the hybrid nanocomposite porous assembly generates short diffusion paths for electrolyte ions and more active sites for reversible faradaic transition for charge storage. The hybrid supercapacitor was assembled using activated carbon as a negative electrode and CCO/NO as a positive electrode in alkaline electrolyte, performed at an improved potential of 1.6 V. Device showed a maximum areal capacitance of 122 mF cm^?2, a maximum areal energy density of 43 μWh cm^?2, and a maximum areal power density of 5.1 mW cm^?2. This hybrid supercapacitor showed remarkable cyclic stability up to 98% for 10,000 cycles. This study encourages the development of low-cost, high-performance, durable electrode designs using hybrid composite for next-generation energy storage systems.     

Anode electrodeposition of 3D mesoporous Fe2O3 nanosheets on carbon fabric for flexible solid-state asymmetric supercapacitor

Novel nanostructured Fe₂O₃ with a network of 3D mesoporous nanosheets was synthesized by depositing on carbon fabric (Fe₂O₃@CF) for use as an anode using a potentially low-cost electrodeposition technique. The electrode with freestanding binder-free Fe₂O₃@CF of high surface area displayed an exceptional specific capacitance of 394.2?F?g^?1. Moreover, a flexible solid-state asymmetric supercapacitor (ASC) was fabricated with a negative electrode based on Fe₂O₃@CF and a positive electrode based on MnO₂@CF in the presence of PVA-LiCl as gel electrolyte. The above ASC exhibited a high operating potential up to 1.8?V, a favorable specific capacitance of 93.5?F?g^?1 (2.92?F?cm^?3), long-term stability (91.3% retention of initial value over 5000 cycles), and remarkable mechanical stability and flexibility, suggesting its potential application for wearable electronics.     

Shell membrane-aided synthesis of 3D porous flower-like Co2(OH)3Cl-MnO2 hybrid composites for high performance supercapacitors

Three-dimensional (3D) flower-like Co₂(OH)₃Cl-MnO₂ nanostructures were fabricated inside eggshell through a facile and effective method. Inspired by semipermeable membranes, a shell membrane was selected as an interface for ion diffusion. In specific, an eggshell with shell membrane was employed as a multifunctional reactor to separate the components of the precursor solution. OH^- ion diffusion was performed through porous eggshell membrane. The electrochemical measurements demonstrated that the hybrid composite achieves high capacitance 3.709?F/cm² at 1?mA/cm² (2061?F/g with the mass loading of 1.8?mg/cm²) and an excellent cycling stability (71% specific capacitance retained after 5000 cycle numbers), exhibiting a superior electrochemical performance compared to pure Co₂(OH)₃Cl or MnO₂. Moreover, an asymmetric supercapacitor was assembled by Co₂(OH)₃Cl-MnO₂-2 and activated carbon as positive and negative electrode, respectively (Co₂(OH)₃Cl-MnO₂-2//AC ASC), which exhibits high capacitance (134.8?F/g at 0.2?A/g), excellent energy density (42.2?W?h/kg at 150.3?W/kg), and remarkable cycling stability (80% capacitance retention after consecutive 5000 cycle numbers).     

Fabrication of PANI@Ti3C2Tx/PVA hydrogel composite as flexible supercapacitor electrode with good electrochemical performance

Developing a new strategy to effectively prevent the restacking of MXene nanosheets will have significant impacts on designing flexible supercapacitor electrodes. Herein, a novel Ti₃C₂T_x/polyvinyl alcohol (PVA) porous sponge with 3D interconnected structures is prepared by sol-gel and freeze-dried methods. This Ti₃C₂T_x/PVA porous sponge is used as the template of in-situ polyaniline (PANI) polymerization, and the fabricated PANI@Ti₃C₂T_x/PVA hydrogel composite is applied as flexible supercapacitors electrodes. 1D conductive polymer chains PVA could increase the interlayer spacing of Ti₃C₂T_x nanosheets, which is beneficial to expose more electrochemical active sites. The supercapacitor based on PANI@Ti₃C₂T_x/PVA hydrogel composite exhibits the coexistence of double-layer capacitance and pseudocapacitance behavior. This supercapacitor shows a maximum areal specific capacitance of 103.8 mF cm^?2 at 2 A m^?2, and it also exhibits a maximum energy density of 9.2 μWh·cm^?2 and an optimum power density of 800 μW cm^?2. The capacitance of this supercapacitor is almost not change under different bending angles. Moreover, 99% capacitance retention is achieved after 10 000 charge/discharge cycles of the supercapacitor. The synergistic effect between PANI and Ti₃C₂T_x/PVA composite may improve the number of reactive sites and provide efficient channels for ion diffusion/electron transport.     

Structural and thermoelectric properties of hydrothermal-processed Ag-doped Fe2O3

Fe_2-xAg_xO₃ (0?≤?x?≤?0.04) nanopowders with various Ag contents were synthesized at different hydrothermal reaction temperatures (150?°C and 180?°C). Their structural properties were fully investigated through an X-ray diffraction, a Fourier transform infrared spectroscopy, and an X-ray photoelectron spectroscopy. The hydrothermal reaction temperature, time, and Ag content remarkably affected the morphological characteristics and crystal structure of the synthesized powders. The Fe_2-xAg_xO₃ (0?≤?x?≤?0.04) powders synthesized at 150?°C for 6?h and the Fe_2-xAg_xO₃ (0.02?≤?x?≤?0.04) powders synthesized at 180?°C for 12?h formed the orthorhombic α-FeOOH phase with a rod-like morphology, whereas the Fe_2-xAg_xO₃ (0?≤?x?≤?0.01) powders synthesized at 180?°C for 12?h formed the rhombohedral α-Fe₂O₃ phase with a spherical-like morphology. The Fe_1.98Ag_0.02O₃ fabricated by utilizing Fe_1.98Ag_0.02O₃ powders synthesized at 180?°C showed the largest power factor (0.64?×10^?5 Wm^?1 K^?2) and dimensionless figure-of-merit (0.0036) at 800?°C.     

Honeycomb-like NiCo2O4@Ni(OH)2 supported on 3D N−doped graphene/carbon nanotubes sponge as an high performance electrode for Supercapacitor

In order to increase the energy density of supercapacitor, a new kind electrode material with excellent structure and outstanding electrochemical performance is highly desired. In this article, a new type of three-dimensional (3D) nitrogen-doped single-wall carbon nanotubes (SWNTs)/graphene elastic sponge (TRGN?CNTs?S) with low density of 0.8 mg cm^?3 has been successfully prepared by pyrolyzing SWNTs and GO coated commercial polyurethane (PU) sponge. In addition, high performance electrode of the honeycomb-like NiCo₂O₄@Ni(OH)₂/TRGN-CNTs-S with core-shell structure has been successfully fabricated through hydrothermal method and then by annealing treatment and electrochemical deposition method, respectively. Benefited from 3D structural feature, the compressed NiCo₂O₄@Ni(OH)₂/TRGN-CNTs-S electrode exhibits high gravimetric and volumetric capacitance of 1810 F g^?1, 847.7 F cm^?3 at 1 A g^?1. The high rate performance and long-term stability was also obtained. Furthermore, an asymmetric supercapacitor using NiCo₂O₄@Ni(OH)₂/TRGN-CNTs-S cathode and NGN/CNTs anode delivered high gravimetric and volumetric energy density of 54 W h kg^?1 at 799.9 W kg^?1 and 37 W h L^?1 at 561.5 W L^?1. In summary, an excellent electrochemical electrode with new elastic 3D SWNTs/graphene supports and binder free pseudocapacitive materials was introduced.     

Thermoelectric properties of Bi2O3-added WO3 ceramics

Tungsten trioxide (WO₃) ceramics were prepared by firing Bi₂O₃-added WO₃ compacts with atomic ratios of Bi/W?=?0.00, 0.01, 0.03, or 0.05, in which Bi₂O₃ was mixed as a sintering agent. Dense ceramics consisting of remarkably grown WO₃ grains were obtained for Bi-containing samples with Bi/W?=?0.01, 0.03, and 0.05. The grain growth was enhanced by the liquid phase of Bi₂W₂O₉ formed among the WO₃ grains while firing. The XRD patterns did not show evidence for Bi inclusion into the WO₃ lattice, but the SEM-EDX showed an intensive distribution of Bi into the grain boundaries. Electrical conductivity σ and Seebeck coefficient S were measured in a temperature range of 373–1073?K. The temperature dependences indicated that the Bi₂O₃-added WO₃ ceramics were n-type semiconductors. It was considered that the electron carriers were generated from oxygen vacancies included into the WO₃ grains. The thermoelectric power factors S²σ for the ceramics ranged from 1.5?×?10^?7 W?m^?1 K^?2 to 2.8?×?10^?5 W?m^?1 K^?2, and the highest value occurred at 970?K for the ceramic with Bi/W?=?0.01.     

Synergistic effect in structural and supercapacitor performance of well dispersed CoFe2O4/Co3O4 nano-hetrostructures

Herein, we report a facile homogeneous urea – assisted hydrothermal approach for the design of CoFe₂O₄/Co₃O₄ nano hetrostructure. A variation in Co concentration leads to smartly designed composite material namely CFC-11 and CFC-12 where CFC-12 appreciates the benefits of both CoFe₂O₄ and Co₃O₄ nanoparticles. The physico – chemical properties of as developed materials were investigated by X-ray diffraction (XRD), field emission electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM), X-ray photoelectron microscopy (XPS) and Raman spectroscopy. The specific surface area and pore size distribution was determined by Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halendo (BJH) respectively. Magnetic measurements via. vibrating sample magnetometer (VSM) demonstrate that saturation magnetization decreases with the incorporation of Co₃O₄ antiferromagnetic nanoparticles. To explore the utility of as designed nano-hetrostructures as supercapacitor electrodes, we employed cyclic voltammetry (CV) and electrochemical impedence spectroscopy (EIS) measurements. A high specific capacitance of 761.1?F?g^?1 at 10?mV?s^?1, admirable cyclic durability of 92.2% and a low resistance value obtained from impedence measurements was observed for CFC-12. The favorable performance demonstrates the synergistic effect of CoFe₂O₄ and Co₃O₄ nanoparticles and thus promise an excellent material for energy storage devices.     

Solvent dependent morphological modification of micro-nano assembled Mn2O3/NiO composites for high performance supercapacitor applications

The different attractive morphologies of micro-nano assembled sphere, pseudo sphere, rock candy and cube-like Mn₂O₃/NiO composites were synthesised by the facile solvothermal method through varying the solvents and their volume ratio. The structural, morphological and compositional properties of synthesised samples were investigated by using powder X-ray diffraction (XRD), FE-SEM, EDS and XPS. The TG/DTA results confirmed the transformation of MnCO₃/NiCO₃ to Mn₂O₃/NiO structures. XRD results revealed that the synthesised samples exhibited the body-centred cubic of Mn₂O₃ and face-centred cubic of NiO. FESEM images depicted the formation of different micro-nano assembled morphologies. XPS study confirmed the presence of manganese, nickel and oxygen elements and their oxidation states. Pseudocapacitance properties of Mn₂O₃/NiO electrodes were evaluated by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy using 1M KOH electrolyte solution. The specific capacitance values of all the synthesised samples were calculated and the morphology of rock candy like Mn₂O₃/NiO composite exhibited superior properties of high specific capacitance of 566.21 Fg^?1 at a current density of 0.5 Ag^?1, better rate capability of 63.25% and good cycling stability of 87.42% capacitance retention even after 1000 cycles. From these results, the well morphological ordered Mn₂O₃/NiO composites may be preferred as the future electrode materials for electrochemical supercapacitor energy storage devices.     

Electrophoretic deposition of ZnCo2O4 spinel and its electrocatalytic properties for oxygen evolution reaction

In this paper, ZnCo₂O₄ was deposited on nickel substrate by electrophoretic deposition (EPD) method as electrocatalyst for the oxygen evolution reaction. The effect of electrophoresis variables including the deposition time, the applied voltages was discussed. XRD, SEM, and electrochemical measurement techniques were used to characterize the deposit and ZnCo₂O₄/Ni electrode. Compared with the ZnCo₂O₄ electrode prepared by nitrate decomposition method, the electrophoretic ZnCo₂O₄ electrodes exhibit better electrocatalytic properties and higher mechanical stability. And the electrode prepared at 10 V for 5 min has the best electrocatalytic properties with the overpotential of only 0.203 V at current density of 100 mA cm⁻².     

Wrapping mesoporous Fe2O3 nanoparticles by reduced graphene oxide: Enhancement of cycling stability and capacity of lithium ion batteries by mesoscopic engineering

The fast capacity fading at high current density turns out to be one of the key challenges limiting the broad applications of transition metal oxide-based electrodes. Herein, Fe₂O₃ nanoparticles with well-defined mesopores wrapped by reduced graphene oxide (RGO) have been synthesized via a facile hydrothermal strategy. The as-prepared nanocomposites were systematically characterized. XPS and Raman analyses confirm the co-existence of Fe₂O₃ and RGO in the nanocomposite system. SEM and TEM reveal that the mesoporous Fe₂O₃ nanoparticles have a size of 20–60?nm and are uniformly dispersed and tightly wrapped by RGO. When used as the anode in lithium ion batteries, the mesoporous-Fe₂O₃/RGO electrode exhibits excellent cycling stability (1098?mA?h?g^?1 after 500 cycles at 1?A?g^?1) and superior rate capability (574?mA?h?g^?1 at 5?A?g^?1). The excellent electrochemical performance can be mainly ascribed to the unique mesoscopic architecture that serves as a cushion to alleviate volume change of Fe₂O₃ during discharge/charge cycles, provides a sustainably large contact area with the electrolyte, and improves electrical conductivity. This unique nanocomposite electrode holds great potential as an anode material for advanced lithium ion batteries.     

Facile preparation of Ni-doped MnCO3 materials with controlled morphology for high-performance supercapacitor electrodes

Doping homogeneous elements and conducting morphological adjustment as commonly-used modification methods are both effective to promote the electrochemical properties of electrode materials. In this work, nickel-doped manganese carbonate with 3D flower-like structure was synthesized by a one-step hydrothermal method, and the corresponding growth mechanism was investigated. The electrochemical characteristics of as-fabricated electrode materials were measured, among which 3D self-assembled Ni_0.2Mn_0.8CO₃ nanoflower with large surface area exhibited superior areal capacitance of 583.5?F?g^?1 at 1?A?g^?1 (fourfold more than MnCO₃ microcubes), excellent electrical conductivity as well as satisfactory cycling stability (84.78% capacitance retention after 2000 cycles at 2?A?g^?1). In addition, the asymmetric supercapacitor assembled with Ni_0.2Mn_0.8CO₃ as cathode and commercial activated carbon as anode displayed a high energy density of 24.1?Wh?kg^?1 at the power density of 0.74?kW?kg^?1 and showed a desirable cycle life. In summary, the unique 3D flower-like Ni_0.2Mn_0.8CO₃ nanomaterial could be regarded as a promising electrode material for high-performance supercapacitors.     

Carbon-coated Bi5Nb3O15 as anode material in rechargeable batteries for enhanced lithium storage

Bismuth can alloy with lithium to generate Li₃Bi with the volumetric capacity of about 3765 mAh cm^?3 (386 mAh g^?1), rendering bismuth-based materials as attractive alloying-type electrode materials for rechargeable batteries. In this work, bismuth-based material Bi₅Nb₃O₁₅ @C is fabricated as anode material through a traditional solid-state reaction with glucose as carbon source. Bi₅Nb₃O₁₅ @C composite is well dispersed, with small particle size of 0.5–2.0?µm. The electrochemical performance of Bi₅Nb₃O₁₅ @C is reinforced by carbon-coated layer as desired. The Bi₅Nb₃O₁₅ @C exhibits a high specific capacity of 338.56 mAh g^?1 at a current density of 100?mA?g^?1. And it also presents an excellent cycling stability with a capacity of 212.06 mAh g^?1 over 100 cycles at 100?mA?g^?1. As a comparison, bulk Bi₅Nb₃O₁₅ without carbon-coating only remains 319.62 mAh g^?1 at 100?mA?g^?1, revealing poor cycle and rate performances. Furthermore, in-situ X-ray diffraction experiments investigate the alloying/dealloying behavior of Bi₅Nb₃O₁₅ @C. These insights will benefit the discovery of novel anode materials for lithium-ion batteries.     

V2O3/rGO composite as a potential anode material for lithium ion batteries

V₂O₃ is a promising anode material and has attracted the interests of researchers because of its high theoretical capacity of 1070?mAh?g^?1, low discharge potential, inexpensiveness, abundant sources, and environmental friendliness. However, the development and application of V₂O₃ have been hindered by the low conductivity and drastic volume change of V₂O₃ composites. In this work, V₂O₃/reduced graphene oxide (rGO) nanocomposites are successfully prepared through a facile solvothermal method and annealing process. In this synthesis protocol, V₂O₃ nanoparticles (NPs) are encapsulated by rGO. This unique structure enables rGO to inhibit volume changes and improve the ion and electronic conductivity of V₂O₃. In addition, V₂O₃ NPs, which exhibit sizes of 5–40?nm, are uniformly dispersed on rGO sheets without aggregation. The Li⁺ storage behavior of V₂O₃/rGO is systematically investigated in the potential range 0.01–3.0?V. The V₂O₃/rGO nanocomposite can achieve a high reversible specific capacity of 823.4?mAh?g^?1 under the current density of 0.1?A?g^?1, and 407.3 mAh g^?1 under the high current density of 4.0?A?g^?1. The results of this study provide insight into the fabrication of rGO-based functional materials with extensive applications.     

Hydrothermal preparation of octadecahedron Fe3O4 thin film for use in an electrochemical supercapacitor

A Fe₃O₄ film with regularly edge-affected cubic (octadecahedron) morphology was successfully prepared on stainless steel foil by a simple and benign hydrothermal process. The potential for the use of the film in a supercapacitor was tested by investigating the electrochemical behavior of the Fe₃O₄ film using cyclic voltammetry (CV) and galvanostatic charge/discharge tests. The Fe₃O₄ film showed a CV indicative of a typical pseudocapactive behavior in 1 mol L⁻¹ Na₂SO₃ solution. Furthermore, this film exhibited a specific capacitance of 118.2 F g⁻¹ at the current of 6 mA between −1 and 0.1 V with a capacity retention of 88.75% after 500 cycles.     

Resistive switching behavior and improved multiferroic properties of Bi0.9Er0.1Fe0.98Co0.02O3/Co1-xMnxFe2O4 bilayered thin films

Bilayered Bi_0.9Er_0.1Fe_0.98Co_0.02O₃/Co_1-xMn_xFe₂O₄ (BEFCO/CM_xFO) thin films were deposited by the sol-gel method. Structural variations between the triclinic-P1 and trigonal-R3c:H (two-phase coexistence) phases in the BEFCO layer were observed owing to the trigonal-R-3m:H phase existing in the CM_xFO layer. The oxygen vacancy concentrations of the BEFCO/CM_xFO bilayered films are reduced by Mn-doping in the bottom CFO layer. The BEFCO/CFO films showed high oxygen vacancy concentrations with a high leakage current. This induced changes of the significant potential barrier at the interface between the BEFCO and CM_xFO layers in the processes of electron capture and release. Thus, the BEFCO/CFO film exhibited obvious resistive switching (RS) effect. The high leakage current also caused a fake polarization phenomenon with a blow up of the P-E loop in the BEFCO/CFO films. However, the real and outstanding ferroelectric properties, which resulted from the fewer oxygen vacancies and the 38% triclinic-P1 structure, were obtained in the BEFCO/CM_0.3FO films (P_r~156.3?μC?cm^?2). In addition, the typical capacitance-voltage curve further confirmed its superior ferroelectric performance. The RS effect almost disappeared in the BEFCO/CM_0.3FO bilayered films. Moreover, the enhanced ferromagnetic properties (M_s~100.36?emu?cm^?3, M_r~55.38?emu?cm^?3) were obtained for the BEFCO/CM_0.1FO films, which was attributed to the magnetic properties of BEFCO (a more triclinic-P1 phase and numerous Fe²⁺ ions), in addition to the CM_xFO layer. The introduction of the doped magnetic layer into the bilayered films thus represented a highly effective method for enhancing the multiferroic properties of BFO.     

The effect of TiO2 additive on sinterability and properties of SiC-Al2O3-Y2O3 composite system

In the current research, the effects of TiO₂ additive on mechanical and physical properties of SiC bodies, sintered by liquid phase methods were investigated. Al₂O₃ and Y₂O₃ were used as sintering-aids (10?wt% in total) with an Al₂O₃/Y₂O₃ ratio of 43/57 to provide liquid phase during Sintering. TiO₂ was also used as the oxide additive with an amount ranging from 0 to 10?wt%. After scaling and mixing the starting materials by a planetary mill, the obtained slurry was dried at 100?℃ for four hours. The derived powders were finally pressed under a pressure of 90?MPa. The samples were then pyrolyzed and sintered at 600?℃ and 1900?℃, respectively under argon atmosphere for 1.5?h. Phase analysis showed no trace of TiO₂ after the sintering process, demonstrating the complete TiO₂ to TiC transformation. The results showed that an increase in TiO₂ content up to 5?wt%, led an improvement in all the measured properties including the relative density, hardness, Young's modulus, bending strength, indentation fracture resistance and the brittleness factor, reaching to 96.2%, 24.4?GPa, 395.8?GPa, 521?MPa, 5.8?MPa?m^1/2 and 286.5?×?10^?6 m^?1, respectively. However more than 5?wt% additive resulted in a decrease in all the above-mentioned properties. Microstructural studies demonstrated that crack deflection and crack bridging were the major mechanisms responsible for an increase in the indentation fracture resistance.     

Promising electrode material of Fe3O4 nanoparticles decorated on V2O5 nanobelts for high-performance symmetric supercapacitors

Bundled V₂O₅ nanobelts decorated with Fe₃O₄ nanoparticles (F3V nanostructures) were successfully synthesized to develop a low-cost electrode material for energy storage applications. The synthesized samples were subjected to structural, morphological and electrochemical studies. The Fe₃O₄ nanoparticles decorated over bundled V₂O₅ nanobelts exhibited better electrochemical properties than the pristine Fe₃O₄ nanoparticles and V₂O₅ nanobelts. The electrochemical behavior of the fabricated electrodes was investigated in an electrolyte of 3 M KOH, demonstrated an exceptional specific capacity values of 750.1, 660.3, and 1519 F g^–1 for V₂O₅, Fe₃O₄, and F3V respectively at a current density of 15 A g^–1. The assembled F3V symmetric supercapacitor (SSC) device exhibited an excellent specific capacitance of 93 F g^–1 at a current density of 0.5 A g^–1, delivering energy and power densities of 13 Wh.kg^–1 and 1530 W kg^–1, respectively, and superior long-term cycling stability of ～84% capacity retention over 5000 galvanostatic charge–discharge cycles. These findings demonstrate the extraordinary electrochemical characteristics of the F3V nanostructures, indicating their potential use in energy storage applications.