Date of Graduation
Fall 2017
Degree
Master of Science in Materials Science
Department
Physics, Astronomy, and Materials Science
Committee Chair
Ridwan Sakidja
Abstract
I have investigated the diffusion mechanisms of Li-ion in amorphous lithium phosphite (LiPO3) with addition of sulphur. By applying the nudge elastic band (NEB) method in crystal LiPO3 and Li3PO4, I confirmed the easing of diffusion pathways for Li ion in LiPO3 which is consistent with the previous theoretical finding[1]. From the diffusion study in 0.5 Li2O- 0.5 P2O5 and 0.4 Li2SO4 – 0.6 (Li2O-P2O5) melts above 3000K performed with ab-initio molecular dynamics (AIMD), produces identical outcome as experimental at lower temperatures. I demonstrated the benefit of addition of S in increasing Li+ mobility. I also found that the Li2SO4 addition into the glass results in a characteristic shift in Li-ion vibration to a lower vibrational frequency. In addition, the presence of oxygen surrounding the diffusion pathways appears to be essential in assisting the Li+ mobility in both crystalline and amorphous structures. The activation energy barrier shows similar pattern as reported in experimental analysis with LiPO3[2].
Keywords
diffusion, density functional theory, nudge elastic band, ab-initio molecular dynamics, Li-ion battery, solid state electrolyte
Subject Categories
Materials Science and Engineering
Copyright
© Md Shafiqul Islam
Recommended Citation
Islam, Shafiqul, "DFT Study on the Li Mobility in Li-Ion-Based Solid-State Electrolytes" (2017). MSU Graduate Theses/Dissertations. 3217.
https://bearworks.missouristate.edu/theses/3217
