No abstract

To effectively attenuate unrecognized and/or unwanted exposures to high‐energy γ‐rays which leads to occupational hazards when accumulated in a wide range of industries, nonleaded metal (bismuth(Bi)‐tin(Sn))/polymer and tungsten (W) composites are prepared and tested. A eutectic alloy, BiSn, with a low melting temperature of 139 °C, is applied for the first time to prepare a γ‐ray shielding material. Compounding of the BiSn alloy/polymer is conducted in a twin screw mixer/extruder by exploiting the alloy's low melting temperature. Multilayer BiSn/polymer composites are prepared by pressing the extruded composites. The γ‐ray shielding efficiency of the composite is elucidated on the basis of the K‐edge theory. To make a thinner but more efficient composite, W flakes are laminated onto the BiSn/polymer composite sheet. The produced (BiSn/polymer)/W composite sheet exhibits strong attenuation of γ‐rays, which is found to follow the Beer–Lambert law. A multilayer (BiSn/polymer)/W laminate can offer both a sufficient thickness with flexibility and an effective shielding against γ‐rays to meet the requirements for protective clothing or protective equipment. This work demonstrates that (BiSn/polymer)/W laminates can be used as a reliable Pb‐substitution material to protect the human body from the high‐energy γ‐rays.

Sustainable and scalable fabrication of electrode materials with high energy and power densities is paramount for the development of future electrochemical energy storage devices. The electrode material of a supercapacitor should have high electrical conductivity, good thermal and chemical stability, and a high surface area per unit volume (or per unit mass). Researchers have made great efforts to use two-dimensional (2D) nanomaterials, but the separated 2D plates are re-stacked during processing for electrode fabrication, impeding the transport of ions and reducing the number of active sites. We developed a novel process for manufacturing thin and flexible electrodes using a 2D material (MXene,Ti3AlC2) and a conducting polymer (poly­(3,4-ethylenedioxythiophene), PEDOT). Because the PEDOT layer is electrochemically synthesized, it does not contain the activator poly­(styrene sulfonate). The electrospray deposition technique solves the restacking problem and facilitates the infilling of the gel electrolyte by forming a highly porous open structure across the entire electrode. In the PEDOT/MXene multilayered electrode, the double-layer capacitance increased substantially because of a dramatic increase in the number of accessible sites through the MXene layer. Although applied to solid supercapacitors, these new supercapacitors outperform most aqueous electrolyte supercapacitors as well as other solid supercapacitors.

No abstract