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  1. Free, publicly-accessible full text available January 1, 2024
  2. All-climate temperature operation capability and increased energy density have been recognized as two crucial targets, but they are rarely achieved together in rechargeable lithium (Li) batteries. Herein, we demonstrate an electrolyte system by using monodentate dibutyl ether with both low melting and high boiling points as the sole solvent. Its weak solvation endows an aggregate solvation structure and low solubility toward polysulfide species in a relatively low electrolyte concentration (2 mol L −1 ). These features were found to be vital in avoiding dendrite growth and enabling Li metal Coulombic efficiencies of 99.0%, 98.2%, and 98.7% at 23 °C, −40 °C, and 50 °C, respectively. Pouch cells employing thin Li metal (50 μm) and high-loading sulfurized polyacrylonitrile (3.3 mAh cm −2 ) cathodes (negative-to-positive capacity ratio = 2) output 87.5% and 115.9% of their room temperature capacity at −40 °C and 50 °C, respectively. This work provides solvent-based design criteria for a wide temperature range Li-sulfur pouch cells. 
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  3. Madden, John D. ; Anderson, Iain A. ; Shea, Herbert R. (Ed.)
    Wearable dielectric elastomer actuators (DEAs) have been greatly considered for development of biomedical devices. In particular, a DEA cuff device has the capability of minimizing venous system disorders that occur in the lower limbs such as orthostatic intolerance (OI) and deep-vein thrombosis which are a result of substantial blood pooling. Recent works have shown that DEAs could regulate and even enhance venous blood flow return. This wearable technology orders a new light, low-cost, compliant, and simple countermeasure which could be safely and comfortably worn that includes mobility. In addition, it may supplement or even provide an alternative solution to exercise and medication. This work presents the design, model, and characterization of the DEA cuff device design that is capable of generating significant pressure change. A rolled DEA strip was actuated over a simulated muscle-artery apparatus using a periodic voltage input, and fluid pressure change was directly observed. A force sensitive resistor sensor was used to achieve a more precise pressure measurement. Performance analysis was conducted through frequency response analysis. The results provide a framework for implementing dynamic modelling and control to allow various forms of actuation input. 
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  4. Abstract

    In this work, an organic‐inorganic hybrid crystal, violet‐crystal (VC), was used to etch the nickel foam (NF) to fabricate a self‐standing electrode for the water oxidation reaction. The efficacy of VC‐assisted etching manifests the promising electrochemical performance towards the oxygen evolution reaction (OER), requiring only ~356 and ~376 mV overpotentials to reach 50 and 100 mA cm−2, respectively. The OER activity improvement is attributed to the collectively exhaustive effects arising from the incorporation of various elements in the NF, and the enhancement of active site density. Furthermore, the self‐standing electrode is robust, exhibiting a stable OER activity after 4,000 cyclic voltammetry cycles, and ~50 h. The anodic transfer coefficients (αa) show that the first electron transfer step is the rate‐determining step on the surface of NF‐VCs‐1.0 (NF etched by 1 g of VCs) electrode, while the chemical step involving dissociation following the first electron transfer step is identified as the rate‐limiting step in other electrodes. The lowest Tafel slope value observed in the NF‐VCs‐1.0 electrode indicates the high surface coverage of oxygen intermediates and more favorable OER reaction kinetics, as confirmed by high interfacial chemical capacitance and low charge transport/interfacial resistance. This work demonstrates the importance of VCs‐assisted etching of NF to activate the OER, and the ability to predict reaction kinetics and rate‐limiting step based onαavalues, which will open new avenues to identify advanced electrocatalysts for the water oxidation reaction.

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