Year

2021

Degree Name

Doctor of Philosophy

Department

School of Mechanical, Materials, Mechatronic, and Biomedical Engineering

Abstract

With the growing shortage and continuously consumption of global petroleum resources, the development of renewable energy has become increasingly important. Large-scale commercialization requirements and high power supply capabilities have become the pursuit goals of energy enterprise applications. Among the energy storage devices, alkali-ion batteries, especially lithium-ion batteries (LIBs), have played a critical role in the past decades because of their high energy density and are widely used in many application fields, such as portable electronic devices, mobile phones, and electric vehicles. Silicon-graphite composite anodes are highly potential materials to realize commercialization and replace pure graphite anodes for LIBs, however, keep delicate balance between of silicon and graphite, maintaining high capacity and long cycling stability at same time, is still challenging. Therefore, a Si/carbon/graphite (Si/C/G) composite was fabricated by a facile process, ball milling and carbonization. The as-prepared Si/C/G anode delivers acceptable capacity and high capacity retention. Furthermore, the binder is optimized to improve cycle stability.

Due to the scarcity of lithium resources and large-scale lithium mining, LIBs cannot meet the requirements of becoming a next-stage battery for meeting the scalable market demand gradually. Therefore, it is quite important to develop alternative energy storage devices, such as sodium ion batteries (SIBs) and potassium ion batteries (PIBs), due to the high storage capacity of sodium and potassium resources in the earth's crust. Nevertheless, the energy density of Na is lower than that of Li, because the standard hydrogen voltage of sodium is very high (-2.71 V vs. Eº), which inevitably limits the potential applicability of SIBs.

FoR codes (2008)

0912 MATERIALS ENGINEERING

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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.