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  1. null (Ed.)
  2. Abstract

    Highly disordered amorphous Li7La3Zr2O12(aLLZO) is a promising class of electrolyte separators and protective layers for hybrid or all‐solid‐state batteries due to its grain‐boundary‐free nature and wide electrochemical stability window. Unlike low‐entropy ionic glasses such as LixPOyNz(LiPON), these medium‐entropy non‐Zachariasen aLLZO phases offer a higher number of stable structure arrangements over a wide range of tunable synthesis temperatures, providing the potential to tune the LBU‐Li+transport relation. It is revealed that lanthanum is the active “network modifier” for this new class of highly disordered Li+conductors, whereas zirconium and lithium serve as “network formers”. Specifically, within the solubility limit of La in aLLZO, increasing the La concentration can result in longer bond distances between the first nearest neighbors of Zr─O and La─O within the same local building unit (LBU) and the second nearest neighbors of Zr─La across two adjacent network‐former and network‐modifier LBUs, suggesting a more disordered medium‐ and long‐range order structure in LLZO. These findings open new avenues for future designs of amorphous Li+electrolytes and the selection of network‐modifier dopants. Moreover, the wide yet relatively low synthesis temperatures of these glass‐ceramics make them attractive candidates for low‐cost and more sustainable hybrid‐ or all‐solid‐state batteries for energy storage.

     
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  3. Atomically dispersed metal catalysts have demonstrated superb electrocatalytic activity because of optimal atom efficiency. However, a rational design of low-cost, high-performance single atom catalysts remains a great challenge due to the elusive chemical reactions of the formation of metal active sites. In this work, biomass hydrogel is prepared as a template for mass production of three-dimensional carbon aerogel-supported single metal atom catalysts. By tailoring the structure of the hydrogel templates, the obtained carbon aerogels exhibit an increase of microporous defects which capture and stabilize isolated metal atoms and minimize aggregation during pyrolysis. Extended X-ray absorption fine structure, Mössbauer spectroscopy, and nitrogen adsorption–desorption isotherm measurements indicate that single metal centers of FeN 4 are formed and embedded within the hierarchical porous carbon frameworks. The obtained composites exhibit outstanding catalytic activity towards oxygen reduction in alkaline media, with a high onset potential of +1.05 V and half-wave potential of +0.88 V, as well as excellent durability. Remarkably, when the carbon aerogels are used as the cathode catalyst in an aluminum–air battery, the battery achieves an ultrahigh open-circuit voltage of 1.81 V, large power density of 181.1 mW cm −2 and stable discharge voltage of 1.70 V at 20 mA cm −2 , markedly better than those with commercial Pt/C as the cathode catalyst. 
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