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Unique oblate-like ZnWO4 nanostructures for electrochemical energy storage performances
摘要： Unique ZnWO4 oblate nanospheres (ZWO-ONSs) deposited on Nickel foam (Ni foam) are successfully prepared via facile hydrothermal route. The ZWO-ONSs show high specific surface area of 89.47 m2g-1. The as-prepared nanostructures tested in 3 M KOH aqueous solution, perform excellent electrochemical performances showing specific capacity of 1198 Fg-1 at 1 Ag-1, and high retention rate cyclic stability 96.56% after 1000 cycles at 10 Ag-1. Distinctive binary metal oxide nanoarchitectures are dynamic material for energy storage systems.
关键词： Supercapacitors,ZnWO4,Oblate-like nanostructures,Structural,Energy storage and conversion
更新于2025-09-23 15:23:52
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Understanding the energy storage mechanisms of poly(3,4-ethylenedioxythiophene)-coated silicon nanowires by electrochemical quartz crystal microbalance
摘要： The capacitive properties of electrodes elaborated from the electrochemical deposition of poly(3,4-ethylenedioxythiophene) (PEDOT) coatings onto chemical vapor deposition (CVD)-grown silicon nanowires (SiNWs) were investigated for supercapacitor applications. A high areal capacitance value of 17 mF cm-2 (50 F g-1) was obtained at a scan rate of 100 mV s-1 in a 3-electrode cell configuration. Furthermore, this 3D hybrid nanostructure was analyzed by electrochemical quartz crystal microbalance (EQCM) to correlate the interfacial ionic exchange mechanisms to their electrochemical performance. It was demonstrated that both anions (BF4-) and cations (TBA+) were simultaneously involved in the charge compensation during the oxidation-reduction scans of cyclic voltammetry measurements.
关键词： SiNWs,EQCM,PEDOT,(pseudo)-supercapacitors
更新于2025-09-23 15:23:52
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Free-standing black phosphorus thin films for flexible quasi-solid-state micro-supercapacitors with high volumetric power and energy density
摘要： Micro-supercapacitors (micro-SCs) are significant micro-scale power sources and energy storage components for miniaturized electronic and flexible devices, where electrodes play the key role in determining their electrochemical performance. The efficient intercalation of ions between the stacking layers of 2D layered materials (2DLM) makes them great candidates as thin film electrodes in micro-SCs, where one can achieve much enhanced volumetric capacitance. However, a great challenge is to develop a high-yield production method for high quality 2DLM thin film electrodes. In this work, we have successfully reported a scalable fabrication process for free-standing black phosphorous (BP) thin films, derived from the high quality few-layer BP nanoflakes via a modified electrochemical exfoliation route, for flexible quasi-solid-state micro-SCs (QMSCs). The as-fabricated QMSCs exhibit an excellent stable electrochemical performance at a high scan rate up to 100 V s-1. More importantly, our QMSC device can not only achieve an outstanding energy density of 3.63 mW h cm-3, a remarkable power density of 10.1 W cm-3 and a superior cycle span (94.3% capacity retention even after 50000 cycles), but also deliver the excellent mechanical flexibility is demonstrated by 91.3% capacity retention after 500 mechanical bending cycles. More interesting, to meet the energy density and power density needs for various practical applications, multiple QMSCs can be successfully integrated in parallel or in series, which is demonstrated by lighting up of the red light emitting diode (LED). The BP-based QMSCs can be patterned on a single substrate with flexible photodetectors based the same BP thin film to form a self-powered optoelectronic system.
关键词： thin film,black phosphorous,2D layered materials,micro-supercapacitors,energy storage
更新于2025-09-23 15:22:29
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Diamond nanofeathers
摘要： This paper reports a special diamond nanostructure which we call diamond nanofeathers (DNFs). The nanostructure was discovered after electrochemically etching doped nanocrystalline diamond (NCD) films. With high resolution SEM, we have repeatedly observed highly porous, fractal-like geometry with “shafts”, “barbs” and “barbules” of the DNFs. A DNF has very high aspect ratio, with a height comparable to the thickness of the etched diamond film and a lateral size as small as several nanometers. This diamond nanostructure seems not to belong to either conventionally defined NCD or ultrananocrystalline diamond (UNCD). The Raman spectra tell that after the electrochemical etch, the DNFs have lower signals from the grain boundaries, compared with the Raman spectra before the etch, which suggests the pores of the DNFs was related with mass loss from the grain boundaries. Preliminary electrochemical characterization has observed more than 300× capacitance increase after the DNFs are fabricated out of a NCD film. With the specific pore size and the ease of fabrication, the DNFs could be a great material choice for supercapacitors, batteries, sensors, and solar cells etc.
关键词： Diamond nanofeathers,Supercapacitors,Nanocrystalline diamond,Raman spectra,Electrochemical etching
更新于2025-09-23 15:21:21
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A laser synthesis of vanadium oxide bonded graphene for high-rate supercapacitors
摘要： Graphene is a type of promising electrode material for high-energy and high-power density supercapacitors, but its electrochemical performance is greatly limited by the restacking problem. In this work, we reported a facile approach to synthesis graphene with chemically bonded vanadium oxide (VOx) nanoparticles and demonstrated that chemically-bonded VOx nanoparticles can effectively prevent the graphene sheets from restacking together and hence improve the electrochemical performance. The capacitance of VOx-bonded graphene increases to 272 F/g compared to 183 F/g of pristine graphene in 1 M H3PO4 aqueous electrolyte at 2 A/g. The VOx-bonded graphene also showed improved rate capability in both H3PO4 and ionic liquid electrolytes. The capacitance retention increases to 54.5% from 28.5% at 100 A/g (compare to 2 A/g) in H3PO4 and increases to 65.1% from 46.3% at 2 A/g (compare to 0.2 A/g) in neat ionic liquid. A high energy density of 84.4 Wh/kg is obtained within the voltage window of 4 V in ionic liquid. Even at a high-power density of 1000 W/kg, the VOx-bonded graphene shows a high energy density of 47.3 Wh/kg.
关键词： Vanadium oxides,Laser reduced graphene,High rate,Restacking,Supercapacitors
更新于2025-09-23 15:21:01
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Hydrothermal synthesis of quantum dots dispersed on conjugated polymer as an efficient electrodes for highly stable hybrid supercapacitors
摘要： Hydrothermal synthesis of graphene quantum dots (GQDs) composited with conjugated polymer were investigated the high specific capacitance and cyclic stability of supercapacitor. The situ chemical polymerization method was employed to synthesize the polypyrrole - graphene quantum dots (PPY-GQDs) composite at different concentrations of GQDs. The size, morphology and structural phase of the PPY- GQDs composites was studied by using Transmission Electron Microscope (TEM), Field Emission Scanning Electron Microscope (FESEM), Atomic Force Microscope (AFM) and X-ray diffractometry (XRD) techniques respectively. The optical and electrochemical measurements were carried out by using Ultraviolet-Visible (UV–Vis) Absorption spectroscopy, Photoluminescence Spectroscopy (PL) and electrochemical work station. The cyclic voltammetry (CV) results show enhanced current density and area of CV loop with increasing scan rate and the concentration of GQDs. The Supercapacitor was fabricated by two electrodes owns a high energy density 67.8 Wh/kg and 93 Wh/kg at a power density of 1210 W/kg and 1430 W/kg for PGC1 and PGC3 composites. The highest specific capacitance values 467.32 and 647.54F/g are achieved by PGC1 and PGC3 composite compare to pure PPY. The PPY-GQDs composites achieved excellent cycle stability until the 2000 cycle. Thus, it demonstrates that GQDs is playing a unique and important role in improving the performance of a hybrid supercapacitor device.
关键词： Electrochemical Impedance spectra,Graphene quantum dots,Specific capacitance,Supercapacitors,Polypyrrole
更新于2025-09-23 15:21:01
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Metallic 1T-MoS2 nanosheets and their composite materials: Preparation, properties and emerging applications
摘要： Metallic 1T phase MoS2 nanosheets and their composite materials, with unique structure and unusual properties, have attracted increasing research interest in energy conversion/storage and catalysis in the past few years. In this work, an overview of the recent progress of metallic 1T-MoS2 nanosheets and their composite materials is presented. First, we focused on the controlled synthesis of 1T-MoS2 nanosheets and their composite materials using top-down and bottom-up approaches and their unusual properties while tuning the phase structure. Then, we discussed their promising applications in energy-related areas including hydrogen evolution reaction, supercapacitors, batteries, and photocatalysis. In addition, an in-depth understanding was provided on phase tuning of these advanced materials for improved performance. Finally, the existing challenges and future research in these emerging research areas are also described.
关键词： Batteries,Hydrogen evolution reaction,Metallic 1T-MoS2 nanosheets,Properties,Photocatalysis,Supercapacitors
更新于2025-09-23 15:21:01
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Silicon as a ubiquitous contaminant in graphene derivatives with significant impact on device performance
摘要： Silicon-based impurities are ubiquitous in natural graphite. However, their role as a contaminant in exfoliated graphene and their influence on devices have been overlooked. Herein atomic resolution microscopy is used to highlight the existence of silicon-based contamination on various solution-processed graphene. We found these impurities are extremely persistent and thus utilising high purity graphite as a precursor is the only route to produce silicon-free graphene. These impurities are found to hamper the effective utilisation of graphene in whereby surface area is of paramount importance. When non-contaminated graphene is used to fabricate supercapacitor microelectrodes, a capacitance value closest to the predicted theoretical capacitance for graphene is obtained. We also demonstrate a versatile humidity sensor made from pure graphene oxide which achieves the highest sensitivity and the lowest limit of detection ever reported. Our findings constitute a vital milestone to achieve commercially viable and high performance graphene-based devices.
关键词： device performance,supercapacitors,graphene,humidity sensors,silicon contamination
更新于2025-09-23 15:21:01
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Synergy of PVP and ethanol to synthesize Ni3S4 quantum dots for high-performance asymmetric supercapacitors
摘要： Ni3S4 quantum dots (QDs) have great potential for supercapacitors due to their unique quantum effects, high specific surface area, high water solubility and good stability, but the current preparation process is cumbersome and toxic. Here, we highlighted a facile and environmental-friendly synthesis of Ni3S4 QDs for the first time by virtue of the synergy of polyvinylpyrrolidone (PVP) and ethanol. The synergistic mechanism was revealed by using XRD to investigate the effect of synthesis solvent. When QDs was used as a supercapacitor electrode material, it exhibited excellent electrochemical properties, and the specific capacitance at 1 A g-1 was 1440 F g-1. In addition, Ni3S4 QDs and activated carbon (AC) are assembled into Ni3S4 QDs//AC asymmetric supercapacitor (ASC), which delivered the maximum energy density of 60.4 Wh kg-1. This work provides new ideas for the preparation of QDs and opens up new concepts for the synthesis of nickel sulfide.
关键词： supercapacitors,nickel sulfide,energy storage,environment friendly,PVP,quantum dots
更新于2025-09-23 15:19:57
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A novel design of poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate)/molybdenum disulfide/poly (3,4-ethylenedioxythiophene) nanocomposites for fabric micro-supercapacitors with favourable performances
摘要： Fabric supercapacitors with mechanical flexible and excellent energy storage capacity attract considerable attention for the potential application in wearable smart electronics. A novel ternary composite electrode and assembled all-solid-state fabric supercapacitors are expected to achieve favorable electrochemical performances. The facile vapor phase polymerization method is employed to fabricate the ternary poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate)/molybdenum disulfide/poly (3,4-ethylenedioxythiophene) composite electrodes. The molybdenum disulfide nanograins are incorporated into the conducting polymer matrix which further facilitates the formation of hierarchical porous structures. On account of profitable synergistic effect among three-component materials and porous structure with reinforced electronic/ionic transport, the as-prepared hybrid electrode exhibits a high areal capacitance of 51.01 mF/cm2 at current density of 0.1 mA/cm2, as well as long cycling durability with 93.6% capacitance retention after 5000 cycles of galvanostatic charge/discharge tests. Furthermore, symmetric fabric micro-supercapacitor assembled by the as-prepared electrodes is also evaluated in a belt-shaped device. This assembled device exhibits an energy density of 0.2 μWh/cm2 (1.81 mWh/cm3) and the power density of 0.09 mW/cm2 (0.82 W/cm3). These results of excellent flexibility and favourable capacitive performance indicate a promising application in portable and wearable electronic devices.
关键词： synergistic effect,ternary nanocomposites,porous structure,flexible micro-supercapacitors
更新于2025-09-23 15:19:57