Developing advanced cathode and electrolyte materials for rechargeable Zn-based batteries

• Main Author: Guo, Yuqi
• Other Authors: Madhavi Srinivasan
• Format: Thesis-Doctor of Philosophy
• Language: English
• Published: Nanyang Technological University 2025
• Subjects: Chemistry; Engineering; Other; Aqueous Zn batteries; Sulfur electrochemistry
• Online Access: https://hdl.handle.net/10356/182409
• Institution: Nanyang Technological University

The ever-increasing energy demand in recent years has driven extensive research on various battery technologies. Li-ion batteries are the most widely used power source for electric vehicle applications and large-scale energy storage. However, it is necessary to explore better alternatives due to safety issues and the high cost of Li-ion batteries. Among various battery technologies, aqueous zinc-based batteries are an exceptional candidate because of their high volumetric capacity of zinc metal anodes, nonflammable water-based electrolytes, and the low cost of Zn metal and cathode materials. Despite these advantages, current aqueous zinc-based batteries exhibit limited energy density, significantly lower than traditional Li-ion batteries. They also suffer from rapid capacity decay and poor cycling performance due to side reactions involving the electrolyte and cathode materials. Severe Zn dendrite growth further hampers long-term cycling performance, necessitating frequent replacement of the Zn metal anode in battery packs, which increases overall costs due to replacement and maintenance. To tackle these problems, the thesis work aims to 1) explore high-capacity sulfur cathode materials with rapid reaction kinetics for both high energy and power density in aqueous zinc-based batteries. 2) develop hybrid electrolytes to mitigate side reactions and Zn dendrite growth in aqueous systems, thereby extending the cycle life of these batteries. By employing the developed sulfur cathodes and hybrid electrolytes, high-rate aqueous zinc-based batteries with high energy density were achieved. Additionally, in-depth studies on the mechanisms of various sulfur cathodes in aqueous systems and the protective mechanisms of different hybrid electrolytes were conducted, providing perspectives for designing better aqueous zinc-based batteries in the future.