GEORGIA INSTITUTE OF TECHNOLOGY

Under the provisions of the regulations for the degree

DOCTOR OF PHILOSOPHY

on Tuesday, February 19, 2019

9:00 AM
in MRDC 3515

will be held the

DISSERTATION PROPOSAL DEFENSE

for

Yiran Xiao

"Synthesis of Li, Na Hydroxide Chloride Solid-State Electrolytes and Fabrication of All-Solid-State Batteries"

Committee Members:

Prof. Gleb Yushin, Advisor, MSE

Prof. Faisal Alamgir, MSE

Prof. Meilin Liu, MSE

Prof. Preet Singh, MSM

Prof. Thomas Fuller, ChBE

Abstract:

Li anti-perovskites, as well as their Na analogies, are considered to be excellent candidates for solid-state electrolytes (SSEs) in all-solid-state batteries because of their high ionic conductivities, low melting points, and low fabrication costs. However, the real conductivities of the anti-perovskites are inconclusive due to the discrepancies in reported compositions. In this work, Li and Na hydroxide chlorides were synthesized by a novel approach with short reaction time. The structures and compositions of the SSEs were characterized by XRD, SEM, EDS, and ToF-SIMS. Ionic conductivities were measured by EIS with various symmetrical cells. We found the conductivities of our SSEs are higher than that of similar compositions in previous research. Mechanical properties including the modulus of elasticity and electrochemical properties including voltage stability window will be studied. All-solid-state batteries will be fabricated with commercial cathode and anode materials. The interactions of the electrolytes with the electrodes and the composition of the solid electrolyte interphase (SEI) layers will be carefully investigated.