Peeking across Grain Boundaries in a Solid-State Ionic Conductor

Peeking across Grain Boundaries in a Solid-State Ionic Conductor

Ganapathy, S. (TU Delft RST/Storage of Electrochemical Energy)
Yu, C. (TU Delft RST/Storage of Electrochemical Energy)
Van Eck, Ernst R.H. (Radboud Universiteit Nijmegen)
Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)

2019

The development of high-performance all-solid-state batteries relies on charge transport in solid electrolytes, where transport across grain boundaries often limits their bulk conductivity. The argyrodite Li ₆ PS ₅ X (X = Cl, Br) solid electrolyte has a high conductivity; however, macroscopic diffusion in this material involves complex jump processes, which leads to an underestimation of the activation energy. Using a comprehensive frequency- and temperature-dependent analysis of the spin-lattice relaxation rates, a complete estimation of Li self-diffusion is demonstrated. Another experimental challenge is quantifying the impact of grain boundaries on the total bulk conductivity. Li ₆ PS ₅ Cl and Li ₆ PS ₅ Br have identical crystalline structures, but with ₆ Li MAS NMR, their resonance peaks have different chemical shifts. Exploiting this with two-dimensional ₆ Li- ₆ Li exchange NMR on a mixture of Li ₆ PS ₅ Br and Li ₆ PS ₅ Cl, we observe Li exchange between particles of these two materials across grain boundaries, allowing direct and unambiguous quantification of this often limiting process in solid-state electrolytes.

http://resolver.tudelft.nl/uuid:fe79a2a4-5998-4506-94f6-9f06223bd0ec

https://doi.org/10.1021/acsenergylett.9b00610

2380-8195

ACS Energy Letters, 4 (5), 1092-1097

Institutional Repository

journal article

© 2019 S. Ganapathy, C. Yu, Ernst R.H. Van Eck, M. Wagemaker