Influence of precipitate/supernatant ratio during liquid-phase synthesis of solid electrolyte Li7P3S11

Bo Fan (1) , Quanfeng Zhang (1) , Zhongkuan Luo (1) , Xianghua Zhang (2) , Hongli Ma (2) , Ping Fan (1) , Bai Xue (1)

1 Shenzhen University
2 ISCR - Institut des Sciences Chimiques de Rennes

Delicate control of the precipitate/supernatant ratio in the precursor suspension during liquid-phase synthesis of Li7P3S11 provides information on how the morphology of the impurities affect the ionic conductivity. In this work, the influence of the precipitate/supernatant ratio on the phase structure, the morphology and the ionic conductivity of Li7P3S11 prepared in acetonitrile is studied. It is revealed that in the supernatant-excess region, the excess amorphous "Li2S·P2S5" finally turns into a poorly ionic conductive phase Li4P2S6 which wraps Li7P3S11 particles, increasing the interfacial resistance. In the precipitate-excess region, a thio-LISICON III phase turned from the excess precipitate tends to stay within Li7P3S11 particles, and therefore its negative influence on the total ionic conductivity is not evident. Consequently, a slight composition shift into the precipitate-excess region benefits the ionic conductivity of the resultant solid electrolyte.

Keywords: solid electrolyte; liquid phase synthesis; lithium thiophosphate; ionic conductivity

Domains: Chemical Sciences; Material chemistry

Bo Fan, Quanfeng Zhang, Zhongkuan Luo, Xianghua Zhang, Hongli Ma, et al.. Influence of precipitate/supernatant ratio during liquid-phase synthesis of solid electrolyte Li7P3S11. Solid State Ionics, 2019, 343, pp.115073. ⟨10.1016/j.ssi.2019.115073⟩. ⟨hal-02367902⟩