Year

2021

Degree Name

Doctor of Philosophy

Department

Institute for Superconducting and Electronic Materials

Abstract

Since their first commercialization in the early 1990s, lithium-ion batteries (LIBs) have been widely used in portable devices, electric vehicles (EVs), and hybrid electric vehicles (HEVs), revolutionizing our way of life. Compared to other battery systems such as nickel-cadmium, nickel-metal hydride, and lead-acid batteries, LIBs are unique in their ability to provide high energy density, high output potential, low self-discharge, and to function over a wide working temperature, as well as many other features. The 2019 Nobel Prize in Chemistry was awarded for the development of LIBs, further recognizing the success of LIB commercialization. However, existing commercial LIBs are the current limitation for the rapid development of both EVs and HEVs due to their limited energy densities. Considering that cathode material accounts for the high weight and cost in state-of-the-art LIBs, replacing these materials with cheaper and higher-energy-density candidates is the key to improving battery energy density.

In this regard, high-voltage spinel LiNi0.5Mn1.5O4 (LNMO) is the most promising cathode material to replace current LiCoO2 in the next-generation high-energy-density LIBs. The Co-free LNMO spinel owns a series of advantages over other candidates, including high energy density and high operating voltage, relatively low-cost to the Co-containing counterparts, good thermal stability, high ionic conductivity, etc. However, the rapid capacity decay of LNMO cathode during battery cycling severely hinders its wide application and potential commercialization. Corresponding modification strategies are in urgent need to improve the electrochemical performance of LNMO material.

This thesis is unavailable until Saturday, June 25, 2022

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Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.