Photo-Rechargeable Li-Ion Batteries using TiS2 Cathode

Photo-rechargeable (solar) battery can be considered as an energy harvesting cum storage system, where it can charge the conventional metal-ion battery using light instead of electricity, without having other parasitic reactions. Here a two-electrode lithium-ion solar battery with multifaceted TiS₂–TiO₂ hybrid sheets as cathode. The choice of TiS₂–TiO₂ electrode ensures the formation of a type II semiconductor heterostructure while the lateral heterostructure geometry ensures high mass/charge transfer and light interactions with the electrode. TiS₂ has a higher lithium binding energy (1.6 eV) than TiO₂ (1.03 eV), ensuring the possibilities of higher amount of Li-ion insertion to TiS₂ and hence the maximum recovery with the photocharging, as further confirmed by the experiments. Apart from the demonstration of solar solid-state batteries, the charging of lithium-ion full cell with light indicates the formation of lithium intercalated graphite compounds, ensuring the charging of the battery without any other parasitic reactions at the electrolyte or electrode-electrolyte interfaces. Possible mechanisms proposed here for the charging and discharging processes of solar batteries, based on the experimental and theoretical results, indicate the potential of such systems in the forthcoming era of renewable energies.     

Snoek-Dominated Internal Friction Response in bcc Steel: Relating Experiments With a Multi-scale Atomistic Computational Framework

Metallurgical and Materials Transactions A - Internal friction is often sensitive to microstructural features. However, there is a clear absence of rational approach for decoupling internal...     

Fabrication and mechanical properties of metakaolin-based geopolymer composites reinforced with auxetic fabrics

This work presents a novel experimental study on the use of auxetic fabrics as the main reinforcement in geopolymer composites, aiming at higher energy dissipation in impact demanding applications. For this, a potassium-based geopolymer was reinforced with an auxetic fabric consisting of basalt fiber fillings positioned between helical auxetic yarns (HAY) made of a thermoplastic polyester core, and a stiffer liquid-crystal polymer wrap, which dispersed the load demands into several single elements having different capabilities. The composites were investigated under quasi-static flexural and tensile loadings, in both longitudinal and transverse directions. The latter showed increased mechanical strengths, up to 26 MPa in tension, and 12.8 MPa in flexural strength. Each fiber portion was tested in tension separately, reaching flexible (core) and stiffer (wrap and basalt) responses, whereas HAYs displayed combined performances due to a suitable auxeticity effect, that is, a negative Poisson's ratio. The pullout investigation justified the cracking and delamination of the composites, due to its cyclic lateral area modification, which created a load demand much higher than what the brittle geopolymer can sustain in this type of solicitation. Thermogravimetric analyses helped to predict the use of such configurations under thermal exposure, pointing out that the geopolymer material could be a suitable thermal barrier to prevent sudden degradation of the fabric under these conditions.     

Hierarchical 3D Flower-like Metal Oxides Micro/Nanostructures: Fabrication,Surface Modification,Their Crucial Role in Environmental Decontamination,Mechanistic Insights,and Future Perspectives

Hierarchical micro/nanostructures are constructed by micro-scaled objects with nanoarchitectures belonging to an interesting class of crystalline materials that has significant applications in diverse fields. Featured with a large surface-to-volume ratio, facile mass transportation, high stability against aggregation, structurally enhanced adsorption, and catalytical performances, three dimenisional (3D) hierarchical metal oxides have been considered as versatile functional materials for waste-water treatment. Due to the ineffectiveness of traditional water purification protocols for reclamation of water, lately, the use of hierarchical metal oxides has emerged as an appealing platform for the remediation of water pollution owing to their fascinating and tailorable physiochemical properties. The present review highlights various approaches to the tunable synthesis of hierarchical structures along with their surface modification strategies to enhance their efficiencies for the removal of different noxious substances. Besides, their applications for the eradication of organic and inorganic contaminants have been discussed comprehensively with their plausible mechanistic pathways. Finally, overlooked aspects in this field as well as the major roadblocks to the implementation of these metal oxide architectures for large-scale treatment of wastewater are provided here. Moreover, the potential ways to tackle these issues are also presented which may be useful for the transformation of current water treatment technologies.     

Stable Graphene Membranes for Selective Ion Transport and Emerging Contaminants Removal in Water

Carbon-based materials, such as graphene oxide and reduced graphene oxide membranes have been recently used to fabricate ultrathin, high-flux, and energy-efficient membranes for ionic and molecular sieving in aqueous solution. However, these membranes appeared rather unstable during long-term operation in water with a tendency to swell over time. Membranes produced from pristine, stable, layered graphene materials may overcome these limitations while providing high-level performance. In this paper, an efficient and “green” strategy is proposed to fabricate µm-thick, graphene-based laminates by liquid phase exfoliation in Cyrene and vacuum filtration on a PVDF support. The membranes appear structurally robust and mechanically stable, even after 90 days of operation in water. In ion transport studies, the membranes show size selection (>3.3 Å) and anion-selectivity via the positively charged nanochannels forming the graphene laminate. In antibiotic (tetracycline) diffusion studies under dynamic conditions, the membrane achieve rejection rates higher than 95%. Sizable antibacterial properties are demonstrated in contact method tests with Staphylococcus aureus and Escherichia coli bacteria. Overall, these “green” graphene-based membranes represent a viable option for future water management applications.     

Correction: Snoek-Dominated Internal Friction Response in bcc Steel: Relating Experiments With a Multi-scale Atomistic Computational Framework

Metallurgical and Materials Transactions A -