DFT calculation of NMR parameters for the K doped CsPbF3 solid-state ionic conductor

DFT calculation of NMR parameters for the K doped CsPbF3 solid-state ionic conductor: A small step toward a green vigor

Zhang, Yixuan (TU Delft Mechanical, Maritime and Materials Engineering)

Braga Groszewicz, P. (mentor)
Sluiter, M.H.F. (mentor)
Heringa, J.R. (mentor)
Vasileiadis, A. (mentor)

Delft University of Technology

Materials Science and Engineering

2023-08

The lack of a decent solid-state ionic conductor has hindered the large-scale application of solid-state batteries, which are considered to be the potential game changer for energy transition. The recently reported K doping CsPbF3 material system has shed light on this problem. This material possesses high ionic conductivity and a wide electrochemical stability window at the same time, making it a highly promising candidate for the next-generation fluoride ion solid-state battery. In order to have a clearer understanding of the structural information of this material and to find out what contributes to the outstanding properties it demonstrates, this thesis project uses Density functional theory(DFT) to calculate its ground state properties. Meanwhile, to better understand its local structure, the Nuclear magnetic resonance(NMR) parameters for this material are also calculated using DFT and analyzed in detail. Results generated from the calculations suggest that the coulombic interaction can be utilized to explain the structural deformation upon doping K into the CsPbF3 system. Additionally, the analysis of the optimized cell structure indicates a tendency for the material system to go through a cubic to tetragonal phase transition, which reproduces the trend observed experimentally and offers a potential explanation for the driving force behind it. Further investigation using Nudged elastic band calculations(NEB) also reveals a relatively low energy barrier for vacancies to diffuse in the crystal structure, which provides insight into the high ionic conductivity of this material. The findings manifested in this thesis project could potentially offer improvement directions for the K-doped CsPbF3 system and contribute to the development of other solid-state ionic conductors.

DFT
NMR
Solid state electrolyte
Solid state battery
Materials

http://resolver.tudelft.nl/uuid:c4482f3e-f54c-4439-847c-b3aeaef15c99

2024-12-31

Student theses

master thesis

© 2023 Yixuan Zhang