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The development of improved solid electrolytes (SEs) plays a crucial role in the advancement of bulk‐type solid‐state battery (SSB) technologies. In recent years, multicomponent or high‐entropy SEs are gaining increased attention for their advantageous charge‐transport and (electro)chemical properties. However, a comprehensive understanding of how configurational entropy affects ionic conductivity is largely lacking. Herein we investigate a series of multication‐substituted lithium argyrodites with the general formula Li6+x[M1aM2bM3cM4d]S5I, with M being P, Si, Ge, and Sb. Structure‐property relationships related to ion mobility are probed using a combination of diffraction techniques, solid‐state nuclear magnetic resonance spectroscopy, and charge‐transport measurements. We present, to the best of our knowledge, the first experimental evidence of a direct correlation between occupational disorder in the cationic host lattice and lithium transport. By controlling the configurational entropy through compositional design, high bulk ionic conductivities up to 18 mS cm−1 at room temperature are achieved for optimized lithium argyrodites. Our results indicate the possibility of improving ionic conductivity in ceramic ion conductors via entropy engineering, overcoming compositional limitations for the design of advanced electrolytes and opening up new avenues in the field. [ABSTRACT FROM AUTHOR]

Li2MChO anti-perovskites have lately attracted much attention as potential electrode materials for Li batteries owing to their high and stable specific capacity. It is rather surprising, because in terms of the structure, metal ions share the same crystallographic site. Since the redox potentials of chalcogenide anions S2− or Se2− and transition metal cations are close, anti-perovskites can be classified as bifunctional materials with cationic and anionic electrochemical activity. Their high chemical flexibility combined with redox-active ions make cubic anti-perovskites a rather valuable model system for tuning desired electrochemical properties. Herein, we studied six Li2MSeO compounds with Mn, Fe, and Co and their solid solutions in Li cells and tailed their structural and electrochemical behaviour to the cationic composition. Remarkably, a booster property of Co with the highest Co3+/Co2+ potential with regard to an enhanced electrochemical performance was observed for Li2Fe0.5Co0.5SeO in comparison to Li2FeSeO, although only Fe and Se were involved in the redox process while Co remained inactive. In Li2Fe0.5Mn0.5SeO, less-active Mn facilitated the oxidation of Fe and Se, positively influencing the rate capability in comparison to Li2Co0.5Mn0.5SeO. Thus, we found a direct correlation between the M3+/M2+ standard redox potential and the electrochemical activity of Se2−. [ABSTRACT FROM AUTHOR]

A full series of variously lithiated graphite anodes material LixC6 (0

The Li+ ion conductor Li27−x[P4O7+xN9−x]O3 (x≈1.9) has been synthesized from P3N5, Li3N and Li2O in a Ta ampoule at 800 °C under Ar atmosphere. The cubic compound crystallizes in space group I4‾3d ${I\overline 4 3d}$ with a=12.0106(14) Å and Z=4. It contains both non‐condensed [PO2N2]5− and [PO3N]4− tetrahedra as well as O2− ions, surrounded by Li+ ions. Charge neutrality is achieved by partial occupancy of Li positions, which was refined with neutron powder diffraction data. Measurements of the partial ionic and electronic conductivity show a total ionic conductivity of 6.6×10−8 S cm−1 with an activation energy of 0.46±0.02 eV and a bulk ionic conductivity of 4×10−6 S cm−1 at 25 °C, which is close to the ionic conductivity of amorphous lithium nitridophosphate. This makes Li27−x[P4O7+xN9−x]O3 an interesting candidate for investigation of structural factors affecting ionic conductivity in lithium oxonitridophosphates. [ABSTRACT FROM AUTHOR]

Phosphide‐based compounds are promising materials for solid electrolytes. In recent times, a multiplicity of compounds featuring isolated MP4 (M = Si,Ge,Sn,Al,Ga) tetrahedra as structural building units in different arrangements with superionic lithium conductivity have been discovered. ω‐Li9AlP4, ω‐Li9GaP4, and ω‐Li9InP4 are presented as new high‐temperature modifications with superionic lithium conductivity reaching 4.5 mS cm−1 at room temperature. Impedance spectroscopy and static temperature‐dependent 7Li NMR experiments reveal conductivity values in the range of 0.2 to 4.5 mS cm−1 at room temperature and low activation energies for the title compounds. X‐ray and neutron diffraction methods disclose that the phosphorus atoms form a cubic‐close packing. The triel element and Li atoms are located in tetrahedral voids, further Li atoms partially fill the octahedral voids. Temperature‐dependent neutron diffraction shows for Li9AlP4 a phase transition at 573 K that influences the occupation of voids with Li and significantly affects the Li‐ion mobility. The evaluation of nuclear scattering densities by the maximum‐entropy approach and application of the one‐particle‐potential formalism reveal 3D lithium diffusion with a low activation energy preferentially on paths of adjacent tetrahedral and octahedral voids. The investigation of different polymorphs suggests that the equilibrated filling of tetrahedral and octahedral voids is a crucial parameter for the enhancement of superionic lithium conductivity. [ABSTRACT FROM AUTHOR]

Vanadate compounds, such as V3O7·H2O, are of high interest due to their versatile applications as electrode material for metal‐ion batteries. In particular, V3O7·H2O can insert different ions such as Li+, Na+, K+, Mg2+ and Zn2+. In that case, well resolved crystal structure data, such as crystal unit‐cell parameters and atom positions, are needed in order to determine the structural information of the inserted ions in the V3O7·H2O structure. In this work, fundamental crystallographic parameters, i.e. atomic displacement parameters, are determined for the atoms in the V3O7·H2O structure. Furthermore, vanadium ions were substituted by molybdenum in the V3O7·H2O structure [(V2.85Mo0.15)O7·H2O] and the crystallographic positions of the molybdenum ions and their oxidation state are elucidated. [ABSTRACT FROM AUTHOR]

A comprehensive understanding of the nexus of diffusion mechanisms on the atomic scale as well as structural influences on the ionic motion in solid electrolytes is key for further development of high-performing all-solid-state batteries. Therefore, current research not only focuses on the search for innovative materials, but also on the study of diffusion pathways and ion dynamics in ionic conductors. In this context, we report on the extended characterization of the ionic electrolyte Li6.5La3Zr1.5Nb0.5O12 (LLZO-Nb). The commercially available material is analyzed by a combination of powder X-ray (either lab- or synchrotron-based) and neutron diffraction. Details of lithium disorder were obtained from high-resolution neutron diffraction data, from which the ionic transport of Li ions was determined by applying the maximum entropy method in combination with the one-particle potential formalism. [ABSTRACT FROM AUTHOR]