The scattering of dark matter (DM) particles with sub-GeV masses off nuclei is difficult to detect using liquid xenon-based DM search instruments because the energy transfer during nuclear recoils is smaller than the typical detector threshold. However, the tree-level DM-nucleus scattering diagram can be accompanied by simultaneous emission of a Bremsstrahlung photon or a so-called "Migdal" electron. These provide an electron recoil component to the experimental signature at higher energies than the corresponding nuclear recoil. The presence of this signature allows liquid xenon detectors to use both the scintillation and the ionization signals in the analysis where the nuclear recoil signal would not be otherwise visible. We report constraints on spin-independent DM-nucleon scattering

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Increasing concerns regarding the sustainability of lithium sources, due to their limited availability and consequent expected price increase, have raised awareness of the importance of developing alternative energy-storage candidates that can sustain the ever-growing energy demand. Furthermore, limitations on the availability of the transition metals used in the manufacturing of cathode materials, together with questionable mining practices, are driving development towards more sustainable elements. Given the uniformly high abundance and cost-effectiveness of sodium, as well as its very suitable redox potential (close to that of lithium), sodium-ion battery technology offers tremendous potential to be a counterpart to lithium-ion batteries (LIBs) in different application scenarios, such as stationary energy storage and low-cost vehicles. This potential is reflected by the major investments that are being made by industry in a wide variety of markets and in diverse material combinations. Despite the associated advantages of being a drop-in replacement for LIBs, there are remarkable differences in the physicochemical properties between sodium and lithium that give rise to different behaviours, for example, different coordination preferences in compounds, desolvation energies, or solubility of the solid–electrolyte interphase inorganic salt components. This demands a more detailed study of the underlying physical and chemical processes occurring in sodium-ion batteries and allows great scope for groundbreaking advances in the field, from lab-scale to scale-up. This roadmap provides an extensive review by experts in academia and industry of the current state of the art in 2021 and the different research directions and strategies currently underway to improve the performance of sodium-ion batteries. The aim is to provide an opinion with respect to the current challenges and opportunities, from the fundamental properties to the practical applications of this technology.

Dual-phase xenon detectors, as currently used in direct detection dark matter experiments, have observed elevated rates of background electron events in the low energy region. While this background negatively impacts detector performance in various ways, its origins have only been partially studied. In this paper we report a systematic investigation of the electron pathologies observed in the LUX dark matter experiment. We characterize different electron populations based on their emission intensities and their correlations with preceding energy depositions in the detector. By studying the background under different experimental conditions, we identified the leading emission mechanisms, including photoionization and the photoelectric effect induced by the xenon luminescence, delayed emission of electrons trapped under the liquid surface, capture and release of drifting electrons by impurities, and grid electron emission. We discuss how these backgrounds can be mitigated in LUX and future xenon-based dark matter experiments.

High‐voltage lithium polymer cells are considered an attractive technology that could out‐perform commercial lithium‐ion batteries in terms of safety, processability, and energy density. Although significant progress has been achieved in the development of polymer electrolytes for high‐voltage applications (> 4 V), the cell performance containing these materials still encounters certain challenges. One of the major limitations is posed by poor cyclability, which is affected by the low oxidative stability of standard polyether‐based polymer electrolytes. In addition, the high reactivity and structural instability of certain common high‐voltage cathode chemistries further aggravate the challenges. In this review, the oxidative stability of polymer electrolytes is comprehensively discussed, along with the key sources of cell degradation, and provides an overview of the fundamental strategies adopted for enhancing their cyclability. In this regard, a statistical analysis of the cell performance is provided by analyzing 186 publications reported in the last 17 years, to demonstrate the gap between the state‐of‐the‐art and the requirements for high‐energy density cells. Furthermore, the essential characterization techniques employed in prior research investigating the degradation of these systems are discussed to highlight their prospects and limitations. Based on the derived conclusions, new targets and guidelines are proposed for further research.

9Poly lactide-co-glycolide (PLGA) is an important polymer matrix used to provide sustained 10 release across a range of active pharmaceutical ingredients (APIs) and works by hydrolytic 11 degradation within the body, thereby releasing entrapped drug. Processing and sterilisation 12 can impact on the morphology and chemistry of PLGA therefore influencing the hydrolysis 13 rate and in turn the release rate of any entrapped API. This paper has looked at the effect of 14 supercritical carbon dioxide (scCO 2 ) processing, gamma irradiation, comonomer ratio and 15 temperature on the hydrolysis of individual PLGA microparticles, using a combination of 16 Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) imaging, Scanning 17 Electron Microscopy (SEM), Differential Scanning Calorimetery (DSC) and Gel Permeation 18 chromatography (GPC) to facilitate a better understanding of the physiochemical factors 19affecting the hydrolysis rate. This work has shown that scCO 2 processing influences 20 hydrolysis rates by increasing the porosity of the PLGA microparticles, increasing the lactide 21 comonomer ratio decreases hydrolysis rates by reducing the hydrophilicity of the PLGA 22 microparticles and increasing the gamma irradiation dose systematically increases the rate of 23 hydrolysis due to reducing the overall molecular weight of the polymer matrix via a chain 24 scission mechanism. Moreover this work shows that ATR-FTIR imaging facilitates the 25 determination of a range of physicochemical parameters during the hydrolysis of a single 26 PLGA microparticle including water ingress, water/polymer interface dimensions, 27 degradation product distribution and hydrolysis rates for both lactide and glycolide 28 copolymer units from the same experiment. 29

LUX-ZEPLIN (LZ) is a second-generation direct dark matter experiment with spin-independent WIMP-nucleon scattering sensitivity above $${1.4 \times 10^{-48}}\, {\hbox {cm}}^{2}$$ 1.4 × 10 - 48 cm 2 for a WIMP mass of $${40}\, \hbox {GeV}/{\hbox {c}}^{2}$$ 40 GeV / c 2 and a $${1000}\, \hbox {days}$$ 1000 days exposure. LZ achieves this sensitivity through a combination of a large $${5.6}\, \hbox {t}$$ 5.6 t fiducial volume, active inner and outer veto systems, and radio-pure construction using materials with inherently low radioactivity content. The LZ collaboration performed an extensive radioassay campaign over a period of six years to inform material selection for construction and provide an input to the experimental background model against which any possible signal excess may be evaluated. The campaign and its results are described in this paper. We present assays of dust and radon daughters depositing on the surface of components as well as cleanliness controls necessary to maintain background expectations through detector construction and assembly. Finally, examples from the campaign to highlight fixed contaminant radioassays for the LZ photomultiplier tubes, quality control and quality assurance procedures through fabrication, radon emanation measurements of major sub-systems, and bespoke detector systems to assay scintillator are presented.

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