Control of Ionic Conductivity by Lithium Distribution in Cubic Oxide Argyrodites Li6+XP1-XSiXO5Cl

Argyrodite is a key structure type for ion-transporting materials. Oxide argyrodites are largely unexplored despite sulfide argyrodites being a leading family of solid-state lithium-ion conductors, in which the control of lithium distribution over a wide range of available sites strongly influences the conductivity. We present a new cubic Li-rich (>6 Li+ per formula unit) oxide argyrodite Li7SiO5Cl that crystallizes with an ordered cubic (P213) structure at room temperature, undergoing a transition at 473 K to a Li+ site disordered F4̅3m structure, consistent with the symmetry adopted by superionic sulfide argyrodites. Four different Li+ sites are occupied in Li7SiO5Cl (T5, T5a, T3, and T4), the combination of which is previously unreported for Li-containing argyrodites. The disordered F4̅3m structure is stabilized to room temperature via substitution of Si4+ with P5+ in Li6+xP1-xSixO5Cl (0.3 x + sites leads to a maximum ionic conductivity of 1.82(1) × 10-6 S cm-1 at x = 0.75, which is 3 orders of magnitude higher than the conductivities reported previously for oxide argyrodites. The variation of ionic conductivity with composition in Li6+xP1-xSixO5Cl is directly connected to structural changes occurring within the Li+ sublattice. These materials present superior atmospheric stability over analogous sulfide argyrodites and are stable against Li metal. The ability to control the ionic conductivity through structure and composition emphasizes the advances that can be made with further research in the open field of oxide argyrodites

Superionic lithium transport via multiple coordination environments defined by two-anion packing

Fast cation transport in solids underpins energy storage. Materials design has focused on structures that can define transport pathways with minimal cation coordination change, restricting attention to a small part of chemical space. Motivated by the greater structural diversity of binary intermetallics than that of the metallic elements, we used two anions to build a pathway for three-dimensional superionic lithium ion conductivity that exploits multiple cation coordination environments. Li 7 Si 2 S 7 I is a pure lithium ion conductor created by an ordering of sulphide and iodide that combines elements of hexagonal and cubic close-packing analogously to the structure of NiZr. The resulting diverse network of lithium positions with distinct geometries and anion coordination chemistries affords low barriers to transport, opening a large structural space for high cation conductivity. </jats:p

Elaboration, structural study and validation of a new NASICON-type structure, Na0.72(Cr0.48,Al1.52)(Mo2.77,Al0.23)O12

The title compound, sodium chromium/aluminium molybdenum/aluminium dodecaoxide, Na0.72Cr0.48Al1.74Mo2.77O12, was prepared by solid-state reaction. Its crystal structure is related to NaSICON-type compounds. The framework is built up from M1O6 (M1 = Cr/Al) octahedra and M2O4 (M2 = Mo/Al) tetrahedra interconnected by corners. The three-dimensional framework contains cavities in which sodium cations are located. Two validation models (BVS and CHARDI) were used to confirm the proposed structural model. The mobility of Na+ ions in the structure has been investigated by theoretical means

Na/Li substitution effect on the structural, electrical and magnetic properties of LiCr(MoO4)2 and β─Li0.87Na0.13Cr(MoO4)2

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Fluorine-Rich Oxyfluoride Spinel Li1.25Ni0.625Mn1.125O3F Utilizing Redox-Active Ni and Mn for High Capacity and Improved Cyclability

Extending the accessible capacity and cyclability is of central interest for cathode materials for Li-ion batteries. Here, we report the successful synthesis of a new spinel Li1.25Ni0.625Mn1.125O3F (Fd3 ̅m) with significant cation disorder characterised by combined refinement of X-ray and neutron diffraction data. Li1.25Ni0.625Mn1.125O3F utilizes redox reactions of both Ni and Mn, accessing capacities of 225 (i.e., 1.46 Li+ capacity) and 285 mAh g-1 (i.e., 1.85 Li+ capacity) at 25 °C and 40 °C, respectively, through intercalation of additional Li+ into the lattice. Moreover, compared to lithium transition metal disordered rocksalt or spinel-like oxyfluorides previously reported, Li1.25Ni0.625Mn1.125O3F shows significantly improved cycling stability. Ex situ compositional, structural and spectroscopic analysis of samples at different states of charge/discharge confirm a single-phase intercalation reaction and high structural integrity over cycling

Fluorine-Rich Oxyfluoride Spinel-like Li1.25Ni0.625Mn1.125O3F Utilizing Redox-Active Ni and Mn for High Capacity and Improved Cyclability

Extending the accessible capacity and cyclability is of central interest for cathode materials for Li-ion batteries. Here, we report the successful synthesis of a new spinel-like Li1.25Ni0.625Mn1.125O3F (Fd3m) oxyfluoride with significant cation disorder characterized by combined refinement of X-ray and neutron diffraction data. Li1.25Ni0.625Mn1.125O3F utilizes redox reactions of both Ni and Mn, accessing capacities of 225 (i.e., 1.46 Li+ capacity) and 285 mAh g-1 (i.e., 1.85 Li+ capacity) at 25 and 40 °C, respectively, through intercalation of additional Li+ into the lattice. Moreover, compared to lithium transition metal disordered rocksalt or spinel-like oxyfluorides previously reported, Li1.25Ni0.625Mn1.125O3F shows significantly improved cycling stability. Ex situ compositional, structural, and spectroscopic analyses of samples at different states of charge/discharge confirm a single-phase intercalation reaction and high structural integrity over cycling

Control of Ionic Conductivity by Lithium Distribution in Cubic Oxide Argyrodites Li_6+<i>x</i>P_1–<i>x</i>Si_<i>x</i>O₅Cl

Argyrodite is a key structure type for ion-transporting materials. Oxide argyrodites are largely unexplored despite sulfide argyrodites being a leading family of solid-state lithium-ion conductors, in which the control of lithium distribution over a wide range of available sites strongly influences the conductivity. We present a new cubic Li-rich (>6 Li+ per formula unit) oxide argyrodite Li7SiO5Cl that crystallizes with an ordered cubic (P213) structure at room temperature, undergoing a transition at 473 K to a Li+ site disordered F4̅3m structure, consistent with the symmetry adopted by superionic sulfide argyrodites. Four different Li+ sites are occupied in Li7SiO5Cl (T5, T5a, T3, and T4), the combination of which is previously unreported for Li-containing argyrodites. The disordered F4̅3m structure is stabilized to room temperature via substitution of Si4+ with P5+ in Li6+xP1–xSixO5Cl (0.3 x < 0.85) solid solution. The resulting delocalization of Li+ sites leads to a maximum ionic conductivity of 1.82(1) × 10–6 S cm–1 at x = 0.75, which is 3 orders of magnitude higher than the conductivities reported previously for oxide argyrodites. The variation of ionic conductivity with composition in Li6+xP1–xSixO5Cl is directly connected to structural changes occurring within the Li+ sublattice. These materials present superior atmospheric stability over analogous sulfide argyrodites and are stable against Li metal. The ability to control the ionic conductivity through structure and composition emphasizes the advances that can be made with further research in the open field of oxide argyrodites

A database of experimentally measured lithium solid electrolyte conductivities evaluated with machine learning

AbstractThe application of machine learning models to predict material properties is determined by the availability of high-quality data. We present an expert-curated dataset of lithium ion conductors and associated lithium ion conductivities measured by a.c. impedance spectroscopy. This dataset has 820 entries collected from 214 sources; entries contain a chemical composition, an expert-assigned structural label, and ionic conductivity at a specific temperature (from 5 to 873 °C). There are 403 unique chemical compositions with an associated ionic conductivity near room temperature (15–35 °C). The materials contained in this dataset are placed in the context of compounds reported in the Inorganic Crystal Structure Database with unsupervised machine learning and the Element Movers Distance. This dataset is used to train a CrabNet-based classifier to estimate whether a chemical composition has high or low ionic conductivity. This classifier is a practical tool to aid experimentalists in prioritizing candidates for further investigation as lithium ion conductors.</jats:p

A database of experimentally measured lithium solid electrolyte conductivities evaluated with machine learning

Abstract The application of machine learning models to predict material properties is determined by the availability of high-quality data. We present an expert-curated dataset of lithium ion conductors and associated lithium ion conductivities measured by a.c. impedance spectroscopy. This dataset has 820 entries collected from 214 sources; entries contain a chemical composition, an expert-assigned structural label, and ionic conductivity at a specific temperature (from 5 to 873 °C). There are 403 unique chemical compositions with an associated ionic conductivity near room temperature (15–35 °C). The materials contained in this dataset are placed in the context of compounds reported in the Inorganic Crystal Structure Database with unsupervised machine learning and the Element Movers Distance. This dataset is used to train a CrabNet-based classifier to estimate whether a chemical composition has high or low ionic conductivity. This classifier is a practical tool to aid experimentalists in prioritizing candidates for further investigation as lithium ion conductors