In order to improve the electrochemical performances of lithium–sulfur batteries, it is crucial to understand profoundly their working mechanism and the limitation factors. This communication presents synchrotron-based in situ XRD studies of structural modifications occurring inside the cell upon cycling, since the active material changes constantly its form between solid and liquid phases.

We are reporting the synthesis, the physicochemical, and the hydrogen sorption properties of a novel bcc high entropy alloy Ti_0.30V_0.25Cr_0.10Zr_0.10Nb_0.25. At room temperature, the alloy rapidly absorbs hydrogen reaching a capacity of 2.0 H/M (3.0 wt.%) and forming a dihydride with fcc structure, as confirmed by both synchrotron X-ray diffraction and neutron diffraction. The absorption Pressure–Composition Isotherms corroborated with synchrotron X-ray diffraction prove that the reaction with hydrogen occurs within two steps, i.e., bcc alloy → bcc monohydride → fcc dihydride. The thermodynamic parameters calculated for the second step transformation evidence the formation of a stable dihydride with ΔH_abs = −75 kJ/molH₂. The phase transition during hydrogen/deuterium desorption was investigated by in situ synchrotron X-ray and neutron diffraction confirming a reversible reaction with hydrogen. Furthermore, the cycling properties show a decrease of the capacity over the first cycles followed by a stabilization at 2.44 wt.%, whereas the absorption kinetics improve after the first cycle reaching full capacity after only 30 s at room temperature.

A suitable solid electrolyte can turn the long‐standing dream of a safe commercial all‐solid‐statebattery into reality in the same way as appropriate liquid electrolytes kickstarted the first commercial lithium‐ion battery. Presently, halide‐based electrolytes despite their reactivity with lithium metal are extensively studied as they offer better processability, malleability, oxidative stability, and safety over sulfide‐based electrolytes. Particularly, LiMCl₆ (M = Ta/Nb) chloride‐based amorphous electrolytes are generating widespread interest with their high conductivities, comparable to liquid electrolytes. In this context, with synchrotron X‐ray and neutron powder diffraction techniques, well‐crystallized triclinic layered LiMCl₆ (M = Ta/Nb) chlorides with an hcp AB‐type stacking of chloride ions is reported. The hexagonally ordered NbCl₆ octahedra share edges with LiCl₆ octahedra forming a honeycomb pattern, whereas Li⁺ is intermixed with M⁵⁺ for M = Ta. Furthermore, it is found that crystalline LiTaCl₆ has an ionic conductivity of ≈10⁻⁵ mS cm⁻¹, six orders of magnitude lower than that reported for superionic amorphous LiTaCl₆. Nevertheless, crystalline LiTaCl₆ is utilized as an intercalation compound in an all‐solid‐state‐battery, uncovering a solid‐solution/two‐phase/conversion pathway for lithium‐insertion during the three distinct redox plateaus below 3 V versus Li⁺/Li°. Broadly, the findings give insights into the structure, ionic conduction, and intercalation in a new family of layered halides.

In this contribution dedicated to kidney stones containing Whitlockite (Wk), we addressed three questions, namely, the presence of iron in Wk, the relationship between bacterial imprints and the presence of Wk, and finally the relationship between the crystal size of Wk-bearing stones and infection. The complete dataset indicates that iron is not present in our Wk stoichiometry. We also note the presence of bacterial imprints for kidney stones with a high, but sometimes a low content, of Wk. Finally, we propose FE-SEM as a diagnostic tool for stone patients who have a negative urine culture associated with kidney stones containing less than 20% by weight Wk, a low level of carbonate in apatite, and no struvite. Such a diagnostic tool would represent a significant benefit to the clinician.