Synthesis and structure of novel lithium-ion conductor Li{sub 7}Ge{sub 3}PS{sub 12}
- Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori, Yokohama 226-8502 (Japan)
The novel lithium-ion conductor Li{sub 7}Ge{sub 3}PS{sub 12} was synthesized by slow cooling from the ternary Li{sub 2}S–GeS{sub 2}–P{sub 2}S{sub 5} system, and was shown to exhibit a cubic argyrodite-type structure. The phase composition was determined by varying the ratio of starting materials; the observed monophasic properties were close to those for the Li{sub 7}Ge{sub 3}PS{sub 12} composition. The lattice parameter (a =9.80192(3) Å) of Li{sub 7}Ge{sub 3}PS{sub 12} was slightly smaller than that of Li{sub 7}PS{sub 6} (a =9.993 Å), indicating that substitution of a Li cation by the smaller Ge cation contracted the cubic lattice. In addition, the novel structure consisted of a framework composed of four isolated (Ge/P)S{sub 4} tetrahedra. Li{sup +} ions occupied tetrahedral sites within the framework, forming a three-dimensional conduction pathway. Finally, Li{sub 7}Ge{sub 3}PS{sub 12} exhibited a high ionic conductivity of 1.1×10{sup −4} S cm{sup −1} at 25 °C and an activation energy of 25 kJ mol{sup −1}. - Graphical abstract: A novel Li{sub 7}Ge{sub 3}PS{sub 12} solid lithium ion conductor, with cubic argyrodite strucuture, shows high ion conductivity of 1.1×10{sup –4} S cm{sup –1} with an activation energy of 25 kJ mol{sup –1}. The argyrodite structure consists of (Ge/P)S{sub 4} tetrahedra units along with partial occupation of lithium and germanium at 48 h site. - Highlights: • A novel lithium-ion conductor Li{sub 7}Ge{sub 3}PS{sub 12} was detected. • This was achieved through slow cooling of the ternary Li{sub 2}S–GeS{sub 2}–P{sub 2}S{sub 5} system. • This novel conductor revealed a cubic argyrodite-type structure. • Li{sub 7}Ge{sub 3}PS{sub 12} exhibited a high ionic conductivity of 1.1×10{sup −4} S cm{sup −1} at 25 °C. • These properties will aid in the design of superior lithium-ion conductors.
- OSTI ID:
- 22658202
- Journal Information:
- Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Vol. 246; ISSN 0022-4596; ISSN JSSCBI
- Country of Publication:
- United States
- Language:
- English
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