Abstract
Li-ion conductors are pivotal materials for all-solid-state Li batteries requiring high energy densities and operational safety. PS4-based thio-phosphate materials have been intensively investigated as solid electrolytes; however, studies on more stable P2S6-based materials are scarce. We herein report on the application of Zn-substituted Li4P2S6, Li4−2xZnxP2S6, as a Li-ion conductor. Owing to the slightly smaller ionic radius of Zn2+ than Li+, the unit cell volume decreases gradually upon Zn substitution without introducing significant structural changes. However, the ionic conductivity of the substitution phase was improved by 104 times (3.8 × 10−6 S cm−1) at x = 0.75 compared to unsubstituted Li4P2S6, which was achieved by generating deficiency on the Li sites via substitution. Such Li-ion deficient site enables Li ions to hop from one site to another in the crystal structure. The 3D diffusion pathway analysis using bond-valence-landscape-energy calculations suggests that the Li diffusion pathways are mostly two-dimensional in the ab plane in this structure. This study shows that an appropriate Li defect concentration within a given structure is critical to improving ionic conductivity.
Original language | English |
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Article number | 123861 |
Journal | Journal of Solid State Chemistry |
Volume | 320 |
DOIs | |
State | Published - Apr 2023 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2023 Elsevier Inc.
Funding
This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (Grant no. 2020R1A2C2007070 and no. 2020R1A4A4079810 ).
Funders | Funder number |
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Ministry of Science, ICT and Future Planning | 2020R1A2C2007070, 2020R1A4A4079810 |
National Research Foundation of Korea |
Keywords
- All-solid-state battery
- LiZnPS
- Lithium-ion conductor
- Solid electrolyte
- Thio-phosphate material