Solid Solution of Bi and Sb for Robust Lithium Storage Enabled by Consecutive Alloying Reaction.

Materials with alloying reactions have significant potential as electrodes for lithium-ion batteries (LIBs) due to its high theoretical capacity and appropriate lithiation potentials. Nonetheless, their cycling performance is inferior due to violent volume expansion and severe pulverization of active materials. Herein, solid solution of Bi0.5 Sb0.5 encapsulated with carbon is discovered to enable consecutive alloying reactions with manageable volume change, suitable for developing LIBs with high capacity and robust cyclability. A Sb-rich shell and Bi-rich core structure is formed in cycling since the alloying reaction between Sb and Li occurs first, followed by the alloying reaction between Bi and Li. Such a consecutive alloying reaction obeying the thermodynamic path is experimentally realized by the carbon capsulation, which acts as a protecting solid layer to avoid polarized reactions occurred when exposed directly to liquid electrolyte. The LIBs using Bi0.5 Sb0.5 @carbon run on the consecutive alloying reactions exhibits high capacity, prolonged lifespan (489.4 mAh g-1 after 2000 cycles at 1 A g-1 ) and fast kinetic, while those using bare Bi0.5 Sb0.5 suffer from worsened kinetic and thus a poor cycling performance owning to the polarized reactions. The work paves a way of developing alloy electrodes for alkaline-ion rechargeable batteries with potential industry applications.

Nanowires for Electrochemical Energy Storage.

Nanomaterials provide many desirable properties for electrochemical energy storage devices due to their nanoscale size effect, which could be significantly different from bulk or micron-sized materials. Particularly, confined dimensions play important roles in determining the properties of nanomaterials, such as the kinetics of ion diffusion, the magnitude of strain/stress, and the utilization of active materials. Nanowires, as one of the representative one-dimensional nanomaterials, have great capability for realizing a variety of applications in the fields of energy storage since they could maintain electron transport along the long axis and have a confinement effect across the diameter. In this review, we give a systematic overview of the state-of-the-art research progress on nanowires for electrochemical energy storage, from rational design and synthesis, in situ structural characterizations, to several important applications in energy storage including lithium-ion batteries, lithium-sulfur batteries, sodium-ion batteries, and supercapacitors. The problems and limitations in electrochemical energy storage and the advantages in utilizing nanowires to address the issues and improve the device performance are pointed out. At the end, we also discuss the challenges and demonstrate the prospective for the future development of advanced nanowire-based energy storage devices.

SAMLDroid: A Static Taint Analysis and Machine Learning Combined High-Accuracy Method for Identifying Android Apps with Location Privacy Leakage Risks.

Insecure applications (apps) are increasingly used to steal users' location information for illegal purposes, which has aroused great concern in recent years. Although the existing methods, i.e., static and dynamic taint analysis, have shown great merit for identifying such apps, which mainly rely on statically analyzing source code or dynamically monitoring the location data flow, identification accuracy is still under research, since the analysis results contain a certain false positive or true negative rate. In order to improve the accuracy and reduce the misjudging rate in the process of vetting suspicious apps, this paper proposes SAMLDroid, a combined method of static code analysis and machine learning for identifying Android apps with location privacy leakage, which can effectively improve the identification rate compared with existing methods. SAMLDroid first uses static analysis to scrutinize source code to investigate apps with location acquiring intentions. Then it exploits a well-trained classifier and integrates an app's multiple features to dynamically analyze the pattern and deliver the final verdict about the app's property. Finally, it is proved by conducting experiments, that the accuracy rate of SAMLDroid is up to 98.4%, which is nearly 20% higher than Apparecium.

Revolutionizing Lithium Storage Capabilities in TiO2 by Expanding the Redox Range.

TiO2 is a widely recognized intercalation anode material for lithium-ion batteries (LIBs), yet its practical capacity is kinetically constrained due to sluggish lithium-ion diffusion, leading to a lithiation number of less than 1.0 Li+ (336 mAh g-1). Here, the growth of TiO2 crystallites is restrained by integrating Si into the TiO2 framework, thereby enhancing the charge transfer and creating additional active sites potentially residing at grain boundaries for Li+ storage. This strategy is corroborated by the expanded redox range of Ti, as thoroughly demonstrated via synchrotron radiation-based X-ray spectroscopy and Cs-corrected electron microscopy. Consequently, when deployed for lithium storage, the tailored material achieves an extraordinarily high reversible capacity of 559 mAh g-1, 116% of the theoretical maximum of 483 mAh g-1 calculated based on all active species, while simultaneously retaining superior rate capability and robust cycling stability. This work offers fresh perspectives on the revitalization of traditional electrode materials to achieve enhanced capacities.

Surface Oxidation Layer-Mediated Conformal Carbon Coating on Si Nanoparticles for Enhanced Lithium Storage.

Si is a well-known high-capacity lithium-ion battery anode material; however, it suffers from conductivity and volume expansion issues. Herein, we develop a "surface oxidation" strategy to introduce a SiOx layer on Si nanoparticles for subsequent carbon coating. It is found that the surface SiOx layer could facilitate the conformal resin coating process through strong interactions with phenolic resin, and well-defined core@double-shell-structured Si@SiOx@C can be obtained after further carbonization. Without the surface SiOx layer, only a negligible fraction of Si nanoparticles can be encapsulated into the carbon matrix. With enhanced conductivity and confined volume change, Si@SiOx@C demonstrates high reversible capacity as well as long-term durability.

CNN-MHSA: A Convolutional Neural Network and multi-head self-attention combined approach for detecting phishing websites.

Increasing phishing sites today have posed great threats due to their terribly imperceptible hazard. They expect users to mistake them as legitimate ones so as to steal user information and properties without notice. The conventional way to mitigate such threats is to set up blacklists. However, it cannot detect one-time Uniform Resource Locators (URL) that have not appeared in the list. As an improvement, deep learning methods are applied to increase detection accuracy and reduce the misjudgment ratio. However, some of them only focus on the characters in URLs but ignore the relationships between characters, which results in that the detection accuracy still needs to be improved. Considering the multi-head self-attention (MHSA) can learn the inner structures of URLs, in this paper, we propose CNN-MHSA, a Convolutional Neural Network (CNN) and the MHSA combined approach for highly-precise. To achieve this goal, CNN-MHSA first takes a URL string as the input data and feeds it into a mature CNN model so as to extract its features. In the meanwhile, MHSA is applied to exploit characters' relationships in the URL so as to calculate the corresponding weights for the CNN learned features. Finally, CNN-MHSA can produce highly-precise detection result for a URL object by integrating its features and their weights. The thorough experiments on a dataset collected in real environment demonstrate that our method achieves 99.84% accuracy, which outperforms the classical method CNN-LSTM and at least 6.25% higher than other similar methods on average.

Porous V2O5 microspheres: a high-capacity cathode material for aqueous zinc-ion batteries.

Porous V2O5 microspheres are synthesized via spray-drying and employed as the cathode material for aqueous zinc-ion batteries (ZIBs). The obtained porous V2O5 microspheres exhibit an ultrahigh reversible capacity and superior rate and cycling performances. In particular, a discharge capacity of 401 mA h g-1 can be achieved at 100 mA g-1. The specific energy density reaches 286 W h kg-1, surpassing most reported V-based cathode materials. The super electrochemical performances demonstrate that the porous V2O5 microsphere is a promising cathode material for aqueous ZIBs.