Unconventional Synthesis of Metal (Ni, Co, Ag) Antimony Alloy Particles.

Bimetallic alloy materials attract interest owing to their properties and stability compared to pure metals, especially alloys with nanoscale dimensions. Metal antimony (MSb) alloys, specifically NiSb, are widely used for charge storage applications due to their high stability. Most synthetic approaches to form these materials require drastic conditions (e.g., high temperatures, potent reducing agents, and extended reaction times), limiting control over the final morphology. The other viable approach is a galvanic replacement that uses unstable materials as precursors. In this work, we present a new and facile method to prepare several MSb (M = Ni, Co, Ag) alloys with shape control by reacting Sb2S3 particles with a metal(M)-sulfide single source precursor in trioctylphosphine (TOP) under mild conditions. Furthermore, we explore the role of TOP as a reducing agent and demonstrate how both alloy constituents are crucial for mutual stabilization. Electrochemical studies are also performed on these NiSb particles, showing their ambipolar nature and allowing their utilization as the active ingredient in the demonstrated high-energy-density symmetric supercapacitor.

Sensing Exposure Time to Oxygen by Applying a Percolation-Induced Principle.

The determination of food freshness along manufacturer-to-consumer transportation lines is a challenging problem that calls for cheap, simple, reliable, and nontoxic sensors inside food packaging. We present a novel approach for oxygen sensing in which the exposure time to oxygen-rather than the oxygen concentration per se-is monitored. We developed a nontoxic hybrid composite-based sensor consisting of graphite powder (conductive filler), clay (viscosity control filler) and linseed oil (the matrix). Upon exposure to oxygen, the insulating linseed oil is oxidized, leading to polymerization and shrinkage of the matrix and hence to an increase in the concentration of the electrically conductive graphite powder up to percolation, which serves as an indicator of food spoilage. In the developed sensor, the exposure time to oxygen (days to weeks) is obtained by measuring the electrical conductivity though the sensor. The sensor functionality could be tuned by changing the oil viscosity, the aspect ratio of the conductive filler, and/or the concentration of the clay, thereby adapting the sensor to monitoring the quality of food products with different sensitivities to oxygen exposure time (e.g., fish vs grain).

Embedded three-dimensional printing of thick pea-protein-enriched constructs for large, customized structured cell-based meat production.

Recent 3D-printing research showed the potential of using plant-protein-enriched inks to fabricate cultivated meat (CM) via agar-based support baths. However, for fabricating large, customized, structured, thick cellular constructs and further cultivation, improved 3D-printing capabilities and diffusion limit circumvention are warranted. The presented study harnesses advanced printing and thick tissue engineering concepts for such purpose. By improving bath composition and altering printing design and execution, large-scale, marbled, 0.5-cm-thick rib-eye shaped constructs were obtained. The constructs featured stable fibrous architectures comparable to those of structured-meat products. Customized multi-cellular constructs with distinct regions were produced as well. Furthermore, sustainable 1-cm-thick cellular constructs were carefully designed and produced, which successfully maintained cell viability and activity for 3 weeks, through the combined effects of void-incorporation and dynamic culturing. As large, geometrically complex construct fabrication suitable for long-term cellular cultivation was demonstrated, these findings hold great promise for advancing structured CM research.

Supercapattery-Diode: Using Layered Double Hydroxide Nanosheets for Unidirectional Energy Storage.

The supercapacitor-diode (CAPode) is a device that integrates the functionality of an ionic diode with that of a conventional supercapacitor. The unique combination of energy storage and rectification properties in CAPodes is relevant for iontronics, alternate current rectifiers, logic operations, grid stabilization, and even biomedical applications. Here, we propose a novel aqueous-phase supercapattery-diode with excellent energy storage [total specific capacity (CT) = 162 C g-1, energy density = 34 W h kg-1 at 1.0 A g-1] as well as rectifying properties [rectification ratio I (RRI) of 23, and rectification ratio II (RRII) of 0.98]; the unidirectional energy storage is achieved by the utilization of an ion-selective redox reaction of battery-type layered double hydroxide (LDH) nanosheets serving as the electroactive material as well as asymmetric device configuration of supercapattery-diode in the KOH electrolyte. This work expands the types of CAPodes and importantly exemplifies the significance of integrating battery-type LDH and their redox chemistry, allowing a simultaneous increase in charge storage and rectification properties.

Vegetable-Oil-Based Intelligent Ink for Oxygen Sensing.

An oil-based composite is employed to monitor the exposure to oxygen inside food packaging, aiming at evaluating the package integrity and the freshness of food. The composite is an oxygen-sensitive printable ink consisting of electrically conductive silver microflakes, embedded in a vegetable oil matrix. The sensitivity of the oil to oxygen is driven by its high content of unsaturated fatty acids that polymerize and shrink upon exposure to atmospheric oxygen. Shrinkage increases the silver concentration and induces percolation, manifested by a steep increase in the electrical conductivity of the composite. We found that the electrical conductivity of the composite is related to its exposure time to air. Employing linseed oil as a matrix demonstrates an increase in electrical conductivity from 10-11 to 10-3 S/cm after only 6 days of exposure to air. We also show that this time span could be modified by changing the oil type to fit various expiration periods of food products.