The practical application of rechargeable aqueous zinc ion batteries (AZIBs) is severely hindered by their poor stability, sluggish kinetics, and limited specific capacity. Based on the synergetic effect of trifluoro-substituted graphdiyne (3F-GDY), a full-graphdiyne-based AZIB is designed that achieves simultaneous regulation of cathodic and anodic electrochemical performance with enhanced lifespan, capacity, and fast-charging property. 3F-GDY@Zn||3F-GDY@NVO full cell exhibits specific capacity of 486.0 mA h g-1 at current density of 0.1 A g-1 with stable cycling performance of over 4000 cycles at 1 A g-1, 7000 cycles at 5 A g-1 and 10000 cycles at 10 A g-1.The synergetic effects of 3F-GDY for AZIBs are further investigated via electrochemical and ex situ characterization techniques, as 3F-GDY possesses porous structure, strong interaction between F atoms and zinc ions, and robust strength. These results bring new perspectives to the fabrication of high-performance AZIBs.

The electrodeposition method is commonly used for fabricating water splitting catalysts. Traditional methods assume a static precursor solution, ignoring the effects of solution dynamics. We theorized that stirring the solution during electrodeposition could improve mass transfer and current distribution, thereby enhancing electrochemical kinetics and nucleation. Consequently, we developed a novel electrodeposition technique to synthesize Fe -doped NiSe, an effective catalyst for alkaline water hydrolysis, demonstrating exceptional performance and stability. This catalyst notably decreases the overpotentials for OER and HER to 185/266 mV and 101/271 mV at 10 and 300 mA cm -2 , respectively. At the same time, the overall water splitting system comprising this catalyst requires only a low potential of 1.48 V to stably catalyze water splitting for over 60 hours. Electrochemical tests indicate that stirred deposition endows the catalyst with a larger electrochemically active area. In -situ Raman spectroscopy reveals NiOOH as an active phase, and Fe doping facilitates NiOOH formation at lower overpotentials, enhancing OER performance. First -principles calculations suggest that Fe doping optimizes the rate -determining step, lowers the activation energy for the OER process, and boosts conductivity. This study presents a method to improve OER efficiency in Ni-based catalysts, offering insights into mechanism control.

Transition metal selenides (TMSes) are regarded as promising anodes for potassium ion batteries (PIBs) benefit from their high theoretical capacity. However, the slow kinetics of potassium ion transport, poor charge transfer ability and short cycle life limit the development of transition metal selenide anode. In this article, the dice-shaped NiCo2Se4@N-doped carbon (NCS@NC) nanocomposite is designed for efficient and stable potassium storage. The in-situ formed carbon shell can not only act as a highly conductive framework to accelerate charge transfer, but also limit the volume fluctuation caused by the potassium ion repeated insertion/ extraction process. The in-situ and ex-situ characterization as well as theoretical calculation show that the heterogeneous interface formed by the heterogeneous metal species in NCS@NC spontaneously establish internal electric fields, which significantly accelerates the ion transport. As results, advanced NCS@NC anode with greatly enhanced electrochemical performance is obtained due to the synergy between the three-dimensional structure design and the heterogeneous interface strategy. NCS@NC anode displays extraordinary rate capacity (471.9 mAh g-1 at 2 A g-1) and ultralong cycle life at high current density (454.5 mAh g-1 at 2 A g-1 after 1000 cycles), which indicates that our modification strategy provides an alternative solution for designing advanced PIBs anodes.

High content N-doped porous carbon (NPC) has been fabricated and used as SIBs anode material. The NPC delivers a high capacity (230.1 mAh g(-1) at 0.1 A g(-1)), excellent rate capability (195.8 mAh g(-1) at 5 A g(-1)) and cycling stability (201.1 mAh g(-1) at 1 Ag-1 after 500 cycles). The excellent performances are ascribed to the unique porous structure and high content of N doped in NPC, they can also provide more active sites for Na+ ions accommodation and generate plenty of channels for the Na+ ions/electron transmission, which can greatly improve its pseudocapacitive effect and buffer the volume expansion during the cycling. The excellent Na+ ions storage capability makes the NPC a promising anode material for SIBs. (C) 2019 Elsevier B.V. All rights reserved.

Aqueous Zn//MnO2 batteries are emerging as promising large-scale energy storage devices owing to their cost-effectiveness, high safety, high output voltage, and energy density. However, the MnO2 cathode suffers from intrinsically poor rate performance and rapid capacity deterioration. Here, we remove the roadblock by compositing MnO2 nanorods with highly conductive graphene, which remarkably enhances the electrochemical properties of the MnO2 cathode. Benefiting from the boosted electric conductivity and ion diffusion rate as well as the structural protection of graphene, the Zn//MnO2-graphene battery presents an admirable capacity of 301 mAh g(-1) at 0.5 A g(-1), corresponding to a high energy density of 411.6 Wh kg(-1). Even at a high current density of 10 A g(-1), a decent capacity of 95.8 mAh g(-1) is still obtained, manifesting its excellent rate property. Furthermore, an impressive power density of 15 kW kg(-1) is achieved by the Zni/MnO2-graphene battery. (C) 2019 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.

Graphene for energy storage devices suffers from the preparation method and deficient quality, hindering their further widespread application. Here, we report a facile and cost-effective approach to derive three-dimensional porous graphene (3DPG) from biocompatible chitosan for massive production. Taking advantage of the large surface area, excellent electrical conductivity and high electrochemical activity of the 3DPG, an advanced symmetric supercapacitor (3DPG//3DPG SCs) is achieved by coupling two 3DPG electrodes in commercial DLC301 organic electrolyte. The device delivers a remarkable capacitance of 168.9 F g-1 at the scan rate of 10 mV s-1 and displays a superior rate capability, witnessing 81.5% capacitance retention from 10 to 100 mV s-1. Furthermore, the 3DPG//3DPG SCs exhibits prominent cyclic durability, as evidenced by its 96% capacitance after 10000 cycles. This work might shed light on the probable application of graphene at industrial level for efficient energy storage.

Using porous carbon derived from waste biomass as electrode material for supercapacitors is a hot topic. It reuses waste at low cost. In this work, JZn-850 is prepared from waste wine industry by treatment with ZnCl2. JZn-850 BET surface area is up to 1103 m(2) g(-1). And it exhibits specific capacitance is 187 F g(-1) at the current density of 0.5 A g(-1) . This is better than other commercial carbon materials such as carbon nanotubes (36 F) and graphene oxide (162 F). JZn-850 also has superior rate capability, from 0.5A g(-1) to 20 A g(-1); its specific volume retention rate is 83.8%. As a new type of electrode material, it has potential applications in supercapacitors and other energy storage materials.

The smallest cyclic ammonium salt reported to date,N,N-dimethylpyrrolidinium tetrafluoroborate(P 11 -BF 4 ),was successively synthesized using a synthesis route without metal ions and halogen ions,then investigated as the electrolyte with Propylene carbonate in ED LCs.The electrochemical cha racte ristics of EDLCs assembled by 1 mol/L P 11 -BF 4 /PC paired with activated carbon electrodes were compared to traditional electrolytes.P 11 -BF 4 has proven to have superior voltage resistance by using cyclic voltammetry and constant current charge-discharge testing.Moreover,P 11 -BF 4 exhibits a more brilliant rate performance due to its high conductivity.These results demonstrate that P 11 -BF 4 is an ideal electrolyte to improve the energy density and power density of supercapacitors.

A facile, low-cost, and efficient electrochemical exfoliation method is demonstrated to prepare three-dimensional nitrogen-doped graphene frameworks on a large scale. Benefiting from the enhanced specific surface area, increased conductivity and enriched active sites, the nitrogen-doped graphene framework electrode exhibits remarkable capacitance, good cyclic stability, and superior rate capability (65.3% capacitance retention), outperforming most of the reported graphene-based electrodes.

The exploration of high-energy and stable cathode materials is highly desirable and challenging for the development of advanced Zn-based batteries. In this work, a facile pyrolysis method is reported to synthetize Ni3S2/carbon nanocomposite as high-performance cathode by employing ion exchange resin as a precursor. Attributing to the abundant active sites and enhanced conductivity from well binding between Ni3S2 and carbon, a markedly high capacity of 234.3 mA h g(-1) is obtained for this Ni3S2/carbon at a high current density of 6.9 A g(-1). Moreover, a Zn-based battery is demonstrated by using the Ni3S2/carbon as a cathode and Zn plate as an anode, which delivers a maximum power density of 58.6 kW kg(-1), together with a peak energy density of 356 W h kg(-1) and 93.7% capacity retention after 5000 charging-discharging cycles. This simple synthetic strategy to achieve robust Ni-based composite electrodes may open up new opportunities to design other transition metal-based electrodes for energy storage applications.

Carbonaceous anode materials are commonly utilized in the energy storage systems, while their unsatisfied electrochemical performances hardly meet the increasing requirements for advanced anode materials. Here, activated amorphous carbon (AAC) is synthesized by carbonizing renewable camellia pollen grains with naturally hierarchical structure, which not only maintains abundant micro- and mesopores with surprising specific surface area (660 m2 g-1), but also enlarges the interlayer spacing from 0.352 to 0.4 nm, effectively facilitating ions transport, intercalation, and adsorption. Benefiting from such unique characteristic, AAC exhibits 691.7 mAh g-1 after 1200 cycles at 2 A g-1, and achieves 459.7, 335.4, 288.7, 251.7, and 213.5 mAh g-1 at 0.1, 0.5, 1, 2, 5 A g-1 in rate response for lithium-ion batteries (LIBs). Additionally, reversible capacities of 324.8, 321.6, 312.1, 298.9, 282.3, 272.4 mAh g-1 at various rates of 0.1, 0.2, 0.5, 1, 2, 5 A g-1 are preserved for sodium-ion batteries (SIBs). The results reveal that the AAC anode derived from camellia pollen grains can display excellent cyclic life and superior rate performances, endowing the infinite potential to extend its applications in LIBs and SIBs.

This paper proposed the line-commutated converter based multi-terminal HVDC(LCC-MTDC) combining with the static synchronous compensator (STATCOM) for doubly-fed induction generator (DFIG) based wind farms integration in the context of Northwest Grid (NG) in China. The control strategies design was approached from two aspects. One was aimed to the ac system on the rectifier side. To coordinate the wind farm, STATCOM and rectifier, the inverse system method was introduced to design the controller in view of the nonlinear characteristic of STATCOM. Meanwhile, the control strategy for the rectifier was proposed to balance the active power in the subsystem and ensure the dc link voltage of STATCOM constant. On the other hand, the single-point voltage control strategy suitable for LCC-MTDC was conceived to guarantee the stable operation of the system by considering the control characteristics of both rectifiers and inverters Simulations carried out in PSCAD/EMTDC have proven that the proposed control strategies possess favorable control performance and fast response speed.

Purpose - The aim of this paper was to study the initial corrosion behavior of copper in the substations of Zhanjiang and Zhuhai.Design/methodology/approach - The copper exposed at the substation of Guangdong coastal region in southern China for up to 12 months. The rust layer formed on the copper has been examined by scanning electron microscopy, X-ray energy spectrum, X-ray diffraction and electrochemical polarization techniques.Findings - The corrosion weight loss of copper at Zhanjiang exposure site is a little more serious than that at Zhuhai exposure site in every exposure period. The corrosion products of copper have different changes in color and composition at the two exposure sites. The tensile strength of copper has a slight decrease after one-year exposure.Originality/value - The atmospheric exposure experiments of copper in the substations of Zhanjiang and Zhuhai have been adopted for the first time. The corrosion behavior of copper was investigated, and it can provide reference for material selection of the substation.

Alumina (Al 2 O[Formula: see text] coated nano silicon was synthesized by aluminothermic reduction for the first time. It was realized by preoxidation of the nano silicon followed by a aluminothermic reduction that transformed the surface silicon oxide into Al 2 O 3 . The thickness of Al 2 O 3 can be controlled by regulating the preoxidized temperature and the processing time. The nano silicon coated with 2–4[Formula: see text]nm Al 2 O 3 showed a more stable cycling performance and a higher coulombic efficiency than the uncoated nano silicon. It is believed that the improved electrochemical performance was benefited from the Al 2 O 3 coating, which could hinder the side chemical reactions during the cycling process. This work provides an alternative method for surface coating on nanomaterials by safe and flexible solid state chemical reaction.

Titanium and nitrogen codoped LiFePO4 was synthesized via a simple solid state reaction using TiN as the dopant source. The morphology, structure, valence state and electrochemical performance of all the samples were investigated and compared with the undoped LiFePO4. The results showed that the codoped samples maintained an olivine structure with modified lattice parameters and exhibited a prominent improved electrochemical performance. Among all the codoped samples, LiFe0.94Ti0.04PO4σN0.04 showed the best rate capability of 108.1 mAh g -1 even at a high rate of 5 C and exhibited a capacity retention of about 94% after 100 cycles at 1 C.

Core–shell Si/Cu nanocomposites were synthesized via a flexible self-limiting surface reaction without extra reductant for the first time. The nano Si was uniformly coated with Cu nanoparticles with a diameter of 5–10[Formula: see text]nm, which can enhance the electronic conductivity of the nanocomposites and buffer the huge volume change during charge/discharge owing to its high ductility. Benefited from the unique structure, the Si/Cu nanocomposites exhibited a good electrochemical performance as anodes for lithium ion batteries, which exhibited a capacity retention of 656[Formula: see text]mAh/g after 50 cycles and a coulombic efficiency of more than 99%.

In order to improve the utilization rate of the electrolyte and further reduce the energy storage cost, the physicochemical properties, electrochemical characteristics and charge/discharging behaviors of VFB with different concentration of VOSO4 and H2SO4 were investigated systematically. The physicochemical characterizations show that the viscosity increases with the increasing concentration of VOSO4 and H2SO4, and the conductivity increases with the increasing concentration of H2SO4 while decreases with the increasing concentration of VOSO4. Both CV and EIS results demonstrate that the electrolyte with 1.6 mol L-1 VOSO4 and 2.8 mol L-1 H2SO4 presents the best electrochemical performance because of the coupling effect of the viscosity, conductivity and electrochemical activity. Different with the half-cell electrochemical tests, the battery performance of VFB is not only dependent on the electrochemical activity of electrode/electrolyte interface, but also closely related to the conductivity of electrolyte and diffusion rates of the active particles between anolyte and catholyte. Taking the battery efficiencies and capacity into consideration, VFB with 1.6 mol VOSO4 and 2.8 mol L-1 H2SO4 exhibits the optimal electrochemical performance. The accomplishment of this work not only gives data support to the fundamental research of VFB, but also provides theoretical direction to the engineering application of VFB. (C) 2016 Elsevier B.V. All rights reserved.

Compared with the basal-planes of highly oriented pyrolytic graphite (HOPG), the edge-planes of HOPG exhibit a significantly enhanced electrochemical performance, indicating of the better electrocatalytic activity of the edge-planes at graphite electrode toward vanadium redox reactions, especially for the positive reaction. In order to further investigate the electrocatalytic activity of the edge plane sites, glass carbon (GC) modified by graphite powders (GP) with different particle sizes, which possess different content of the edge-planes, are used as electrodes and their physicochemical properties such as the morphology, microstructure, surface composition, and specific surface area, in addition to the corresponding electrochemical characteristics have been characterized systematically. The total electrochemical activity toward vanadium redox reaction increases greatly with the decrease of the particle sizes for GP, which mainly attributes to the increasing surface area and exposed edge plane sites. It is worth note that a large surface area often means abundant edge plane sites, and it is mainly in favor of the enhancement of the current response, while the proportion of the active area such as the edge-planes in total surface area to a large extent determines the electrocatalytic activity.