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Influence of the synthesis method on electrical storage capacity of graphene-related materials
摘要： The electrochemical properties and their relationship with the physico-chemical properties of graphene-based materials have been studied. Graphite was used as the raw material and it was oxidised and then reduced by two alternative approaches, namely thermal and multi-step reduction using ascorbic acid. It was demonstrated that the physico-chemical characteristics of the material are directly related to the synthesis method and greatly influence the major capacitance of the material. It was observed that the materials with lower levels of functional oxygen groups and with a more ordered structure, i.e. similar to graphene powder, are the ideal candidates for use in electrochemical applications as these materials have better capacitance and specific capacitances.
关键词： Graphene-related materials,characterisation,supercapacitors,voltammetry
更新于2025-09-19 17:15:36
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P-functionalized and O-de???cient TiOn/VOm nanoparticles grown on Ni foam as electrode for supercapacitor: epitaxial grown heterojunction and visible-light-driven photoresponse
摘要： P-TiOn-VOm nanowires were grown on nickel foam (NF) by one-pot hydrothermal and further vapor deposition/phosphorization method. It is found low valence states of titanium oxide and deficient-oxygen coexist in P-TiOn-VOm/NF. Furthermore, (TiO1.25)3.07 (denoted as TiOn) and VO (denoted as VOm) possess similar structures and matched facets, their epitaxial growth leads to the formation of TiOn/VOm heterostructure with a formation energy of -1.59 eV. P-TiOn-VOm/NF possesses good electron conductivity, and electrons can be transferred from Ti to V centers, as evidenced by DFT calculations and XPS spectra. As a result, the specific capacity of P-TiOn-VOm/NF can reach 785 C g-1 at 1 A g-1 in the potential range of 0~ 0.55 V vs Hg/HgO, which is much larger than those of VOm/NF, P-VOm/NF and P-TiO2-VOm/NF. On the other hand, the TiOn/VOm heterostructure also favors for the separation and transfer of photoinduced electrons and holes, and P-TiOn-VOm/NF exhibits visible-light-driven photoresponse. Under the visible light illumination, the specific capacity of P-TiOn-VOm/NF is increased 6.2 % relative to that in dark. Furthermore, the P-TiOn-VOm/NF//activated carbon (/ AC) asymmetric supercapacitor (ASC) shows an energy density of 37.2 Wh kg-1 at power density of 1 kW kg-1, and excellent cycling performance with 93.6 % capacity retention after 10000 cycles at 5 A g?1, which is comparable to and even superior to those of titanium oxides and vanadium oxides. It is proposed a promising achievement to improve the energy storage performance of P-TiOn-VOm through the P-functionalization and O-deficiency in this work.
关键词： Phosphorus functionalized,Oxygen vacancy,TiOn-VOm,Supercapacitors
更新于2025-09-19 17:13:59
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Effect of surface amphiphilic property of azobenzene self-assembled electrode materials on properties of supercapacitors
摘要： In this report, novel azobenzene self-assembled complexes (azo-Cn, n = 8, 12, 16) were used as an electrode material for pseudo-capacitors. The as-prepared azo-Cn exhibited a good reversible redox process and possessed a specific capacitance as high as 221.0 F g?1 at 10 mV s?1. However, with the value n increased from 8 to 16, the specific capacitances of azo-Cn electrode materials decreased. In order to study the reasons, the effect of surface amphiphilic property of azobenzene self-assembled electrode materials on the properties of supercapacitors was studied and the results showed that the capacitive behaviors of azo-Cn could be greatly improved by better surface hydrophilic properties and azo-C8 with good supercapacitive characteristics could be the potential ideal electrode materials for low-cost and high-efficiency electrochemical supercapacitors.
关键词： Supercapacitors,Azobenzene,Amphiphilicity,Self-assembly
更新于2025-09-19 17:13:59
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Semitransparent Energya??Storing Functional Photovoltaics Monolithically Integrated with Electrochromic Supercapacitors
摘要： Energy-storing functional photovoltaics, which can simultaneously harvest and store solar energy, are proposed as promising next-generation multifunction energy systems. For the extension of conventional organic photovoltaics (OPVs), electrochromic supercapacitors (ECSs) are monolithically integrated with semitransparent (ST) quaternary blend-based OPVs (ST Q-OPVs) to achieve compact, energy-efficient storage with great aesthetic appeal. In particular, ST Q-OPVs with low-power-consumption ECSs allow full operation, even under low-intensity irradiance, including artificial indoor light circumstances, and thereby exhibit potential for all-day operating energy suppliers. The prepared ST energy-storing functional photovoltaics also serve as a backup power source for external electronic equipment (e.g., light-emitting diodes, and sensor nodes for Internet of Things) by consuming charged power. In addition to features that include unrestricted operation under any circumstances, color tunability, feasibility of designs with various shapes, rapid charging/discharging, and real-time indication of stored energy levels, ST energy-storing functional photovoltaics could potentially be applied in electronic devices such as advanced smart windows or portable smart electronics.
关键词： semitransparent organic photovoltaics,electrochromic supercapacitors,energy-storing functional photovoltaics,monolithic integration
更新于2025-09-19 17:13:59
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Binder- and conductive additive-free laser-induced graphene/LiNi1/3Mn1/3Co1/3O2 for advanced hybrid supercapacitors
摘要： Hybrid supercapacitors have recently emerged as next-generation energy storage devices that bridge the gap between supercapacitors and lithium-ion batteries. However, developing high energy cathodes that maintain long-term cycle stability and a high rate capability for real applications remains a significantly challenging issue. Herein, we report a facile synthesis method for a laser-scribed graphene/LiNi1/3Mn1/3Co1/3O2 (LSG/NMC) composite for high energy cathode materials for use in hybrid supercapacitors. LSG/NMC composites exhibit not only a high capacitance of up to 141.5 F/g but also an excellent capacitance retention of 98.1% after 1000 cycles at a high current density of 5.0 A/g. The introduction of an NMC spacer between the LSG layers provides an enlarged interspace that can act as an efficient channel for additional storage sites and rapid access. In addition, we further confirmed that hybrid supercapacitors using LSG/NMC cathodes and H2Ti2O25 anodes with an AlPO4/carbon hybrid coating layer (H-HTO) deliver a remarkable energy density of ~123.5 Wh/kg, power density of ~14074.8 W/kg, and a long-term cycle stability of 94.6% after 20,000 cycles. This work demonstrates that our proposed material can be considered a strong cathode candidate for next-generation hybrid supercapacitors.
关键词： laser-scribed graphene,high energy density,hybrid supercapacitors,LiNi1/3Mn1/3Co1/3O2,long-term cycle stability
更新于2025-09-19 17:13:59
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Laser graving assisted fabrication of foldable supercapacitors for on-chip energy storage
摘要： Planar supercapacitors (SCs) have been regarded as promising energy devices for on-chip electronics and they should be evaluated by areal performances due to the very limited available areas. However, these SCs usually suffer from inevitable size increase for the requirement of substrates, current collectors and sealants. This work presents a kind of freestanding, foldable and quasi-solid-state SCs that single SC units were stacked in the thickness direction with a common electrode to reduce their occupied areas. The foldable SCs can be fabricated in desired patterns by laser graving and their areal performances increase linearly with the assembled units. The energy density of a 5-units foldable SC is 177.9 μWh cm-2 at the power density of 2.78 mW cm-2 and it outperforms most planar SCs. Therefore, this work provides a new reference to improve the areal properties of on-chip SCs from device design.
关键词： nanocomposites,on-chip energy storage,foldable device,supercapacitors,carbon nanotubes
更新于2025-09-19 17:13:59
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Heating Rate-Controlled Thermal Exfoliation for Foldable Graphene Sponge
摘要： Foldable supercapacitors are desired for the next generation of wearable electronics. In this study, highly foldable graphene sponges with a honeycomb structure are prepared at 300 °C using the convenient thermal exfoliation process. A slow heating rate (5?10 °C·min?1) around 200 °C and an external con?nement force are critical to a favorable exfoliation degree and uniform thickness of the graphene sponges. After being annealed at 1050 °C for 1 h, the conductivity of the graphene sponge has been improved from 2700 to 6900 S·m?1 without degrading its ?exibility. The capacitance of the annealed graphene sponge has been measured in an aqueous electrolyte solution of 1 M Na2SO4. Its best capacitance is 138.74 F·g?1, and it reduces by 3.6% at a half-fold state and by 8.9% at a quarter-fold state.
关键词： wearable electronics,Foldable supercapacitors,honeycomb structure,thermal exfoliation,graphene sponges
更新于2025-09-19 17:13:59
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Exploring Synergistic effect of Ni <sub/>x</sub> Sn <sub/>2x</sub> S <sub/>4x</sub> Thiospinel with MWCNTs with Enhanced Performance in Dye Sensitized Solar cells, Hydrogen Evolution Reaction and as Supercapacitor
摘要： Trifunctional nickel tin sulfide (NixSn2xS4x) thiospinel like structure composited with multiwall carbon nanotubes (MWCNTs) (M–NixSn2xS4x) was synthesized by a facial method. The unit cell arrangement of prepared composite has been studied by Density Functional Theory (DFT) and the theoretical interpretation satisfactorily inferred the presence of synergistic effect between thiospinel and MWCNTs. High metallic conductivity and superior electrocatalytic activities of M–NixSn2xS4x composite plays a prominent diverse roles as counter electrode for dye sensitized solar cells (DSSCs) with 4.67 % efficiency when compared to Pt (5.23 %) at fluorine doped indium tin oxide (FTO), efficient catalyst like Pt for hydrogen evolution reaction (HER) with good cyclic stability and low over potential of ?41 mV at the cathode current density of 10 mA cm2 and Tafel slope of 43 mV/dec at graphite sheet electrode and as impressive capacitance material at graphite sheet electrode alternate to an expensive current collectors like Ni foam with a specific capacitance value of 1,200 Fg?1 at current density of 1 Ag?1 and long life span of 92.6 % retained up to 15,000 cycles.
关键词： HER,Thiospinel,hybrid supercapacitors,cyclic stability,low overvoltage,DSSCs
更新于2025-09-19 17:13:59
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Photovoltaic Synchronous Generator (PVSG): Architecture and Control Strategy for A Grid-Forming PV Energy System
摘要： Transforming conventional PV energy system from a grid following one to a grid forming is necessary when PV power generation is dominating the generation mix and replacing traditional synchronous generators. Grid forming PV energy system can provide frequency support functionality which is vital for the stability of the power grid. This paper presents a novel AC coupled solution that transforms an existing grid following PV system to a grid forming one without any hardware and software modification of the PV inverter. The resulting system, the Photovoltaic Synchronous Generator (PVSG), is achieved by an AC coupled supercapacitor-based energy storage system (ESS). The novel control of the PVSG is implemented in the ESS side. The novel control scheme includes a fast and slow instantaneous power controls. The fast-instantaneous power flow control is fulfilled by the DC-link voltage control and AC voltage control. The cascaded voltage source controls enable the fast-instantaneous power balance, while a slow instantaneous power control is used to implement the inertia and grid synchronization. Two important fundamental functions are realized in the PVSG. The first one is the frequency inertia to resist the grid frequency variation where the df/dt-based power control is achieved; the second one is the inertia against the PV intermittent power. The correctness and effectiveness of the proposed PVSG is validated experimentally in a 480V PVSG prototype with TMS320F28379D DSP controller.
关键词： current controlled,power control,PVSG,virtual synchronous generator (VSG),Inertia,voltage controlled,grid-forming inverter,supercapacitors,energy storage system,inverter control
更新于2025-09-16 10:30:52
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Fabricating Strongly Coupled V2O5@PEDOT Nanobelts/Graphene Hybrid Films with High Areal Capacitance and Facile Transferability for Transparent Solid-State Supercapacitors
摘要： Transparent energy-storage devices are of enormous significance to the continued growth of flexible and wearable electronics in the foreseeable future. The development of transparent supercapacitive electrodes that possess not only high optical transmittance but also intriguing features of energy-storage capability, transferability and outstanding durability, remains a remarkable challenge. Here we demonstrate a polymer-glued strategy to fabricate the conjugated transparent hybrids of V2O5 and graphene, whereby the poly(3,4-ethylenedioxythiophene) (PEDOT) forms a conformal coating on the surface of V2O5 nanobelts and functions as a glue. Interestingly, the PEDOT-glued V2O5/graphene (VP-G) is easy-transferrable onto various flat and even curved substrates. When served as a transparent supercapacitive electrode, the VP-G exhibits a high areal capacitance of 22.4 mF cm?2 at an optical transparency of 70%. As unveiled by experimental results and density functional theory (DFT) calculations, both the kinetic blocking of the PEDOT layer and the anchoring capability of graphene upon soluble vanadium ions contribute synergistically to the unusual electrochemical stability. Transparent, high-energy-density solid-state supercapacitors made of the as-fabricated hybrids are constructed, exhibiting a high energy density of 0.18 μWh cm?2 at 11 μW cm?2. As expected, the constructed transparent supercapacitors demonstrate an excellent cycling stability over 50 000 cycles with capacitance retention of 92.4%. These results show its great potential as promising transparent devices.
关键词： transparent supercapacitors,high stability,high areal capacitance,strongly coupled nanocompsites,transferable electrode
更新于2025-09-16 10:30:52