학술논문
Understanding and mitigating metallic anode degradation in divalent battery systems
Document Type
Electronic Thesis or Dissertation
Author
Source
Subject
Language
English
Abstract
The work in this thesis focuses on the metallic anode in two of the divalent battery systems: aqueous zinc batteries and calcium-ion batteries. By performing systematic studies, we aim to provide a deep understanding of their anode degradation mechanisms: In Chapter 3, I looked at the ageing-induced degradation in ZnSO4-based aqueous zinc batteries. It was found that ageing can lead to significant anode capacity loss, in some cases over 70% efficiency loss after only 24 hours. We assessed such loss with respect to various factors: ageing time, anode loading, cycling rates etc. and investigated the root causes of such ageing-induced capacity loss using in-situ Computed X-Ray Tomography. A paper based on this chapter, 'Decoupling and Quantifying Aging-Induced Zn Anode Degradation Processes in Aqueous Zinc Batteries' has been submitted to 'Joule' and is now under review. In Chapter 4, I explored a possible strategy to mitigate the dendrite problem in the ZnSO4-based aqueous zinc batteries. By using a single-crystal (002) Zn as an ideal model anode, I promoted planar Zn deposition and defect suppression, which largely resolved the dendrite problem and allowed excellent cell performance at high-rate and long-cycle conditions. A paper based on this chapter, 'Achieving Ultra‐High Rate Planar and Dendrite‐Free Zinc Electroplating for Aqueous Zinc Battery Anodes' has been published in 'Advanced Materials'. In Chapter 5, I systematically studied and visualized the plating and stripping process in the Ca(BH4)2-based calcium-ion battery electrolyte using in-situ TEM. I revealed that despite calcium deposition being mostly globular, calcium dendrite formation can still occur as a result of high current density. In addition, the inhomogeneous CaH2 layer formation can also lead to the formation of localized 'hot spots', which can induce unexpected dendrite formation at lower current densities. Two papers based on this chapter, 'Liquid cell transmission electron microscopy and its applications' and 'Current-density-dependent electroplating in Ca electrolytes: From globules to dendrites', has been published in 'Royal Society open science' and 'ACS Energy Letters'.