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With the rapid development of e-commerce recently, massive spammers purposely distort the ranking of goods, which affects the market order and the fair competition of businesses seriously. Therefore, identifying such spammers is significant to rational decision making of customers. However, it is difficult to discriminate between normal users and malicious spammers on extremely large rating networks. In this paper, we propose a common indicator based on the historic rating records from spammers and normal users, which is widely applied to many existing methods. It is inspired by the idea that normal users have their preferences and rating bias shown in rating ladder, while spammers do not have such rating ladders in practice. Such an indicator is complement with other existing methods including Deviation-based Ranking (DR), Iterative Group-based Ranking (IGR) and Iterative Balance Ranking (IBR). Experimental study on three real rating networks shows that this indicator can significantly improve the accuracy of DR, IGR and IBR. To deal with malicious spammers, DR, IGR and IBR are improved by at least 9.38%, 2.90% and 2.53%, respectively. To deal with random spammers, DR, IGR and IBR are improved by at least by 5.52%, 17.12% and 32.24%, respectively. [ABSTRACT FROM AUTHOR]

In cases involving high levels of sulfur loading or high levels of current discharge, constructing sulfur composite cathodes via traditional coating preparation processes is an unsuitable way to overcome intractable problems relating to cathodes for use in lithium–sulfur batteries, such as poor conductivity, severe volume expansion, and the detrimental shuttle effect. Herein, a novel three-dimensional self-supported TiO2@C membrane with hierarchical interlinked porosity and oxygen vacancies was prepared via a phase-inversion method to act as a sulfur host. The procured TiO2−x@C membrane facilitates the infiltration of electrolyte, provides fast lithium-ion and electron transport channels and abundant sulfur loading sites, and shows superb structural buffering against the large volume changes during the conversion process between sulfur and lithium sulfide. More importantly, the introduction of oxygen vacancies not only enhances the conductivity of the original TiO2, but it also improves the corresponding adsorption abilities toward polysulfides and the subsequent transformation dynamics. Therefore, the TiO2−x@C membrane can significantly inhibit the polysulfide shuttle effect through polar chemisorption and conversion catalysis. Based on the above superiorities, the TiO2−x@C/S membrane electrode exhibits an impressive lifespan of more than 500 cycles at 2 C with a prominent ultimate specific discharge capacity of 715.2 mA h g−1. [ABSTRACT FROM AUTHOR]

Nowadays, the development of advanced anode materials is highly desirable for the increasing demand for high‐performance lithium‐ion batteries (LIBs). Nanostructured MnO2 has received utmost attention due to high theoretical capacity (1230 mA h g−1), abundant resources, environmental benignity, and shortened electron and ion diffusion paths. Unfortunately, poor electronic conductivity and strong aggregation inclination of MnO2 nanostructures result in disappointing electrochemical performances, which restrict their practical application as sole institute. Here, we propose smartly designed MnO2@Fe3O4/CNT hybrid films, in which MnO2 nanosheets, Fe3O4 nanoparticles and CNTs are hierarchically assembled in a unique stage of nanosheets–nanoparticles–nanotubes. The resulting MnO2@Fe3O4/CNT hybrid films can be directly used as anodes without any polymer binders, and exhibit significant synergistic interactions among three components, achieving excellent reversible capacity and rate performance. Elegant! MnO2@Fe3O4/CNT hybrid films are smartly designed, in which MnO2 nanosheets, Fe3O4 nanoparticles and CNTs are hierarchically assembled in a unique stage of nanosheets–nanoparticles–nanotubes. The resulting binder‐free hybrid films achieve significant synergistic interactions among three components for superior lithium storage. [ABSTRACT FROM AUTHOR]

Here a new concept is conceived to design CNT@TiO2@Mn3O4 nanostructures, in which CNTs, TiO2 nanosheets and Mn3O4 nanoparticles are hierarchically organized in a three-stage order. In this concept, each component plays a unique, indispensable role. In the first stage, 1D CNTs serve not only as a backbone to accommodate mechanical stress, but also as a conductive dopant to facilitate electron transport. In the second stage, 2D TiO2 nanosheets act as a major active material to ensure high safety and a long cycle life. In the third stage, 0D Mn3O4 nanoparticles function as an auxiliary active material to contribute an extraordinarily high theoretical capacity. Besides, the CNTs can minimize the restacking of the TiO2 nanosheets, thus guaranteeing good structural integrity. TiO2 nanosheets, being flexible and elastic in nature, are able to inhibit the aggregation of Mn3O4 nanoparticles, as well as buffer the volume variation suffered during repeated lithiation/delithiation. Mn3O4 nanoparticles, in turn, are capable of physically isolating the TiO2 nanosheets to enlarge their interlayer distances for easy lithium and electron access. Thanks to the significant synergy, CNT@TiO2@Mn3O4 nanostructures exhibit enhanced cycle and rate performances and represent a new step towards high-performance anode candidates of lithium-ion batteries. [ABSTRACT FROM AUTHOR]

In cases involving high levels of sulfur loading or high levels of current discharge, constructing sulfur composite cathodes via traditional coating preparation processes is an unsuitable way to overcome intractable problems relating to cathodes for use in lithium-sulfur batteries, such as poor conductivity, severe volume expansion, and the detrimental shuttle effect. Herein, a novel three-dimensional self-supported TiO 2 @C membrane with hierarchical interlinked porosity and oxygen vacancies was prepared via a phase-inversion method to act as a sulfur host. The procured TiO 2- x @C membrane facilitates the infiltration of electrolyte, provides fast lithium-ion and electron transport channels and abundant sulfur loading sites, and shows superb structural buffering against the large volume changes during the conversion process between sulfur and lithium sulfide. More importantly, the introduction of oxygen vacancies not only enhances the conductivity of the original TiO 2 , but it also improves the corresponding adsorption abilities toward polysulfides and the subsequent transformation dynamics. Therefore, the TiO 2- x @C membrane can significantly inhibit the polysulfide shuttle effect through polar chemisorption and conversion catalysis. Based on the above superiorities, the TiO 2- x @C/S membrane electrode exhibits an impressive lifespan of more than 500 cycles at 2 C with a prominent ultimate specific discharge capacity of 715.2 mA h g -1 .

Lithium-sulfur (Li-S) batteries face a few vital issues, including poor conductivity, severe volume expansion/contraction, and especially the detrimental shuttle effect during the long-term electrochemical process. Herein, we designed a hierarchical MXene@TiO2 nanoarray via in situ solvothermal strategies followed by heat treatment. The MXene@TiO2 heterostructure achieves superior charge transfer and sulfur encapsulation. Based on the polar-polar and Lewis acid-base mechanism, the robust dual chemisorption capability to trap polysulfides can be synergistically realized through the intense polarity of TiO2 and the abundant acid metal sites of MXene. Hence, the MXene@TiO2 nanoarray as a sulfur host retains a substantially stable discharge capacity of 612.7 mA h g-1 after 500 cycles at a rate of 2 C, which represents a low fading rate of 0.058% per cycle.

Nowadays, the development of advanced anode materials is highly desirable for the increasing demand for high-performance lithium-ion batteries (LIBs). Nanostructured MnO 2 has received utmost attention due to high theoretical capacity (1230 mA h g -1 ), abundant resources, environmental benignity, and shortened electron and ion diffusion paths. Unfortunately, poor electronic conductivity and strong aggregation inclination of MnO 2 nanostructures result in disappointing electrochemical performances, which restrict their practical application as sole institute. Here, we propose smartly designed MnO 2 @Fe 3 O 4 /CNT hybrid films, in which MnO 2 nanosheets, Fe 3 O 4 nanoparticles and CNTs are hierarchically assembled in a unique stage of nanosheets-nanoparticles-nanotubes. The resulting MnO 2 @Fe 3 O 4 /CNT hybrid films can be directly used as anodes without any polymer binders, and exhibit significant synergistic interactions among three components, achieving excellent reversible capacity and rate performance., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)