Boosting Solid-State Diffusivity and Conductivity in Lithium Superionic Argyrodites by Halide Substitution.
Angew Chem Int Ed Engl
; 58(26): 8681-8686, 2019 Jun 24.
Article
en En
| MEDLINE
| ID: mdl-31041839
ABSTRACT
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±0.1â
mS cm-1 at 298â
K (and 12.0±0.2â
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.
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MEDLINE
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En
Revista:
Angew Chem Int Ed Engl
Año:
2019
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Article
País de afiliación:
Canadá