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Combined synchrotron X‐ray nanotomography imaging, cryogenic electron microscopy (cryo‐EM) and modeling elucidate how potassium (K) metal‐support energetics influence electrodeposit microstructure. Three model supports are employed: O‐functionalized carbon cloth (potassiophilic, fully‐wetted), non‐functionalized cloth and Cu foil (potassiophobic, nonwetted). Nanotomography and focused ion beam (cryo‐FIB) cross‐sections yield complementary three‐dimensional (3D) maps of cycled electrodeposits. Electrodeposit on potassiophobic support is a triphasic sponge, with fibrous dendrites covered by solid electrolyte interphase (SEI) and interspersed with nanopores (sub‐10 nm to 100 nm scale). Lage cracks and voids are also a key feature. On potassiophilic support, the deposit is dense and pore‐free, with uniform surface and SEI morphology. Mesoscale modeling captures the critical role of substrate‐metal interaction on K metal film nucleation and growth, as well as the associated stress state. [ABSTRACT FROM AUTHOR]

A strategy for modifying the structure of solid‐state electrolytes (SSEs) to reduce the cation diffusion activation energy is presented. Two heavily W‐doped sodium thioantimonate SSEs, Na2.895W0.3Sb0.7S4 and Na2.7W0.3Sb0.7S4 are designed, both exhibiting exceptionally low activation energy and enhanced room temperature (RT) ionic conductivity; 0.09 eV, 24.2 mS/cm and 0.12 eV, 14.5 mS/cm. At −15 °C the Na2.895W0.3Sb0.7S4 displays a total ionic conductivity of 5.5 mS/cm. The 30 % W content goes far beyond the 10–12 % reported in the prior studies, and results in novel pseudo‐cubic or orthorhombic structures. Calculations reveal that these properties result from a combination of multiple diffusion mechanisms, including vacancy defects, strongly correlated modes and excessive Na‐ions. An all‐solid‐state battery (ASSB) using Na2.895W0.3Sb0.7S4 as the primary SSE and a sodium sulfide (Na2S) cathode achieves a reversible capacity of 400 mAh g−1. [ABSTRACT FROM AUTHOR]

Metal Dendrite, Potassium Ion Battery, Potassium Metal Battery, Potassium Sulfur Battery Keywords: Metal Dendrite; Potassium Ion Battery; Potassium Metal Battery; Potassium Sulfur Battery EN Metal Dendrite Potassium Ion Battery Potassium Metal Battery Potassium Sulfur Battery 1 1 1 05/29/23 20230605 NES 230605 B Using advanced analytical techniques b based on synchrotron and electron microscopy as described in their Research Article (e202300943), Pengcheng Liu, David Mitlin et al. were able to "see" and understand the growth of body centered cubic potassium metal dendrites, depicted in the cover picture as corals growing underwater and away from normal sight. This is represented by the light rays shining down from above. [Extracted from the article]