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Direct-hanged energy storage of voltage source converters （VSCs） on the DC side can be applied to active or reactive power grids. It has the advantages of peak shaving and valley filling， reducing wind and photovoltaic power curtailment. Given the topology of DC-side direct-hanging energy storage of VSCs， the basic working principle of DC-side energy storage is introduced first. Two control methods are proposed： constant DC voltage control and constant DC control at the pole control level. Moreover， DC voltage open-loop control is proposed since both methods adopt feed-forward control of sub-module quantity. Finally， an RTDS （real-time digital simulation system） is established， and steady-state， dynamic， and control mode switching tests are carried out. The results show that the DC-side energy storage with such topology is characterized by its superior steady-state operation， dynamic voltage， and current response characteristics and has a particular application and promotion value.

Titanium silicon molecular zeolite (TS-1) plays an important role in catalytic reactions due to its unique nanostructure. The straight channel on TS-1 was parallel to the orientation of the short b-axis and directly exposed to the aperture of the 10-member ring with a diameter of 0.54 nm × 0.56 nm. This structure could effectively reduce the diffuse restriction of bulk organic compounds during the oxidative desulfurization process. As a kind of cationic polymer electrolyte, polydimethyldiallyl ammonium chloride (PDDA) contains continuous [C8H16N+Cl−] chain segments, in which the Cl− could function as an effective structure-directing agent in the synthesis of nanomaterials. The chain of PDDA could adequately interact with the [0 1 0] plane in the preparation process of zeolite, and then the TS-1 nanosheet with short b-axis thickness (6 nm) could be obtained. The pore structure of the TS-1 nanosheet is controlled by regulating the content of PDDA. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), N2 physical adsorption analysis, infrared absorption spectrum and ultraviolet–visible spectrum were used to determine the TS-1. The thinner nanosheets exhibit excellent catalytic performance in oxidative desulfurization of dibenzothiophene (DBT), in which the removal rate could remain at 100% after three recycles. Here, the TS-1 nanosheet with short b-axis thickness has a promising future in catalytic reactions. [ABSTRACT FROM AUTHOR]

Ternary MoS2/MoO3/C nanosheets were successfully synthesized via a chemical vapor deposition method. The hybrids were characterized by x-ray diffraction, scanning electron microscope, high-resolution transmission electron microscopy, raman and x-ray photoelectron spectroscopic methods. The as-obtained MoS2/MoO3/C nanosheets applied as an anode material for lithium-ion batteries, showed high initial discharge/charge capacities at current rates of 0.5C, 1640.9 mA h g−1 and 1393.8 mA h g−1 respectively, with initial coulombic efficiency of approximately 84.9%. The material exhibited superior rate capabilities, with specific discharge capacities of 1240.2 mA h g−1, 1048.5 mA h g−1, 917.2 mA h g−1, 742.3 mA h g−1, 663.6 mA h g−1, 601.8 mA h g−1 and 593.4 mA h g−1 at current rates of 0.2C, 0.4C, 1C, 4C, 8C, 12C and 15C, respectively. This superior electrochemical performance was mainly due to the uniformly-distributed MoS2 nanosheets and to highly graphitized carbon, which not only mitigated mechanical stress during repeated cycling, but also provided good conductivity. [ABSTRACT FROM AUTHOR]

A multilayer-cake WS2/C nanocomposite was successfully synthesized through an intercalation-transformation method, in which few-layered WS2 and carbon were sandwiched in an alternating sequence. As a benefit of the electronic conductivity enhanced by the interlayer carbon and the unique 'regular' and 'alternate' architecture, the WS2/C nanocomposite showed promising performance as an anode material for lithium-ion batteries. The nanocomposite demonstrated a high capacity of 829.4 mAh⋅g−1 at 0.3 A⋅g−1 after 140 cycles and it could still deliver a stable capacity of about 326.8 mAh⋅g−1 at a current density of 8.0 A⋅g−1. [ABSTRACT FROM AUTHOR]

Fe3O4 is a potential anode material for lithium-ion batteries, because of its environmentally friendliness, high capacity, and inexpensive availability. However, Fe3O4 causes a severe capacity attenuation, owing to a large volume change, and it has a poor rate capability, owing to low conductivity. In this work, Fe3O4 nanoparticles embedded in an olive-shaped carbon skeleton were prepared through the one-step pyrolysis of metal-organic framework (MOF) precursors in a nitrogen atmosphere. The Fe3O4 nanoparticles were evenly embedded in the olive-shaped carbon skeleton and the Fe3O4 particle size was around 23 nm in width and 38 nm in length, which exhibits enhanced cycling and rate performance. The prepared Fe3O4/C material achieves a high initial charge and discharge capacity of 1423.0 mAhg−1 and 925.5 mAhg−1, respectively, and shows a remarkable cycle-stable specific capacity of 877.0 mAhg−1 after 80 cycles at 0.5 C. High specific discharge capacities of 810, 720, 660, 585, 516, 486, and 460 mAhg−1 were obtained at 0.5, 1, 2, 6, 12, 15, and 20 C, respectively. [ABSTRACT FROM AUTHOR]