Nanostructured Si 1-x Ti x alloys (0 ≤ x ≤ 0.3) prepared by ball milling were studied as negative electrode materials in Li cells. The alloys comprised a nanocrystalline and amorphous Si phase and a nanocrystalline C49 TiSi 2 phase. When x ≥ 0.15 the nanocrystalline Si phase was completely eliminated and such alloys consisted only of amorphous Si and the C49 TiSi 2 phase. The alloys with x ≥ 0.15 also completely suppressed the formation of Li 15 Si 4 during cycling, resulting in good capacity retention, and, unlike other Si transition metal alloys, without introducing noticeable cell polarization. The observed capacity of the Si 1-x Ti x alloys suggested that the TiSi 2 is an inactive phase toward Li. Silicon-based materials are of high interest in the pursuit of obtaining higher energy density lithium ion batteries. Pure silicon has an outstanding theoretical capacity of 2194 Ah/L, which has been estimated to provide an increase in energy density of up to 34% in Li-ion cells, compared to cells with conventional graphite-based electrodes. However, the cycle life of Si electrodes is difficult to maintain because of its drastic volume expansion during lithiation (up to 280%). Reducing Li uptake and providing an inactive phase framework is one possible way to alleviate the expansion problem. Some inactive M-Si alloys, such as Ni-Si, 2-4 Fe-Si, 5 Cu-Si, 6 B-Si, 7 have been extensively studied in the past two decades.Si-Ti alloys are of interest as electrode materials for Li-ion batteries because of their thermal stability and because they are composed of high abundance elements. They also have low density and TiSi 2 has high electrical conductivity compared to other silicides. 8 Because of these favorable properties, this system has been studied by other groups in the past. Lee et al. synthesized Si-Ti alloys via melt spinning, forming alloys comprised of well crystallized Si and TiSi 2 phases. 9The observed capacities of these samples in Li cells were far less than expected from the amount of Si present. All the Si in these samples might not have been fully accessible to lithium ions because of the morphology that resulted from rapid solidification processing. Zhou et al. synthesized Si coated TiSi 2 nanonets via chemical vapor deposition.10 When the nanonets were cycled between 0.03-3.0 V, high capacity fade during cycling resulted because of the formation of Li 15 Si 4 . When cycling was conducted above 0.09 V, capacity retention was improved because the formation of Li 15 Si 4 was avoided. This indicates the importance of avoiding Li 15 Si 4 formation to obtain good cycling performance. Park et al. designed a TiSi 2 -coated Si anode via a silicothermic reduction process.11 The conductive silicide coating resulted in improved rate performance. It is apparent from these studies that microstructure and Li 15 Si 4 avoidance is important in obtaining good cycling in Si-Ti alloys. However, to our knowledge a systematic study of the effect of composition in the Si-Ti alloy system has not previously been reported.Here a...

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Superhydrophobic porous materials, for instance, sponges, membranes, and meshes, have attracted great attention due to their ability for adsorption of organic solvents, hydrocarbons, and oils while repelling water. In this work, we report an organic-solvent-free, environmentally benign, and cost-effective preparation method of a bifunctional adsorbent using a melamine sponge coated with few-layer hexagonal boron nitride nanosheets (hBNNs) functionalized with laccase (LA). The hBNNs are used as a building block for immobilizing and stabilizing LA for the removal and degradation of anthracene, a polycyclic aromatic hydrocarbon in crude oil, and to convert them to lighter and less-toxic substances. The physiochemical properties and performance of the sponges for the removal and degradation of anthracene were investigated thoroughly. The highest hydrocarbon degradation of 89% was obtained at an LA concentration of 2.72 mg/mL and pH 7, after 72 h. The degradation increased to 91% after 7 days of functionalized sponge exposure to the medium. Moreover, the functionalized sponges’ reusability studies revealed that the anthracene degradation efficiency was still as high as 54% after the hBNN–polyethylene oxide–LA sponges were repeatedly used 5 times. The strategy proposed for the fabrication of these sponges is facile and easy to scale up, not requiring the use of a complicated process or expensive equipment. These nano-engineered sponges are promising candidates for the separation and degradation of oils and hydrocarbons in oil spill remediation applications.