Fast ion conductor

Physics

Electrode

Organic chemistry

Analytical Chemistry (journal)

Endocrinology

Ionic conductivity

Conductivity

Solid solution

Physical chemistry

Halide

Inorganic chemistry

Chemistry

Metallurgy

Materials science

Lithium (medication)

Thermal diffusivity

Electrolyte

Dielectric spectroscopy

Electrochemistry

Medicine

Thermodynamics

Angewandte Chemie International Edition

Developing high-performance all-solid-state batteries is contingent on finding solid electrolyte materials with high ionic conductivity and ductility. Here we report new halide-rich solid solution phases in the argyrodite Li6 PS5 Cl family, Li6-x PS5-x Cl1+x , and combine electrochemical impedance spectroscopy, neutron diffraction, and 7 Li NMR MAS and PFG spectroscopy to show that increasing the Cl- /S2- ratio has a systematic, and remarkable impact on Li-ion diffusivity in the lattice. The phase at the limit of the solid solution regime, Li5.5 PS4.5 Cl1.5 , exhibits a cold-pressed conductivity of 9.4±0.1 mS cm-1 at 298 K (and 12.0±0.2 mS cm-1 on sintering)-almost four-fold greater than Li6 PS5 Cl under identical processing conditions and comparable to metastable superionic Li7 P3 S11 . Weakened interactions between the mobile Li-ions and surrounding framework anions incurred by substitution of divalent S2- for monovalent Cl- play a major role in enhancing Li+ -ion diffusivity, along with increased site disorder and a higher lithium vacancy population.

Boosting Solid‐State Diffusivity and Conductivity in Lithium Superionic Argyrodites by Halide Substitution