Ionic conduction mechanisms in 70Li2S−30P2S5 type electrolytes: experimental and atomic simulation studies

Youngin Lee, Young Hoon Kim, Jae Hyun An, Jae Chul Lee

Research output: Contribution to journalArticlepeer-review

Abstract

Although understanding the structure-property relationship in solid electrolytes is pivotal to develop electrolytes with improved properties, previous studies examined only the partial effect of the structures and did not consider the realistic operating environments. Here, experimental investigations and theoretical simulations are used to explore the collective effects of crystal structure, temperature, and electric field on the ionic conductivity of various electrolytes with the 70Li2S−30P2S5 composition. Each electrolyte sample is composed of a mixture of three distinct crystalline phases: γ-Li3PS4, Li7P3S11, and Li4P2S6, each of which is comprised of the PS4, P2S7, and P2S6 substructures in varying fractions and spatial distributions. Atomic simulations confirm that the abundant stable Li interstitial sites in these crystals, particularly Li7P3S11, shorten the jumping distance for Li self-diffusion. On the other hand, charge polarization of the P2S7 cluster amplifies its oscillatory motion in the presence of an electric field and at ambient temperatures, thereby widening the Li diffusion passage. The reduction in the Li jumping distance, as well as the widening of the diffusion passage, reduce the energy barriers for Li diffusion, allowing for fast Li transport. While the present findings fill the knowledge gaps regarding the ionic conduction mechanisms of the 70Li2S−30P2S5 electrolytes, they also provide design criteria for developing highly conductive solid electrolytes.

Original languageEnglish
Article number118106
JournalActa Materialia
Volume235
DOIs
Publication statusPublished - 2022 Aug 15

Keywords

  • DFT calculation
  • Ionic conductivity
  • Li diffusion pathway
  • Raman spectroscopy
  • Sulfide solid electrolytes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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