Synergistic Artificial Interlayer to Enhance the Homogeneity of Zinc-ion Flux for Dendrite-free Zinc Metal Anodes
Creators: Wang, Jialiang
Publisher: name: University of Alberta Library
Year: 2023

<p>The decreasing availability of fossil fuels and increasing environmental concerns highlight the necessity to seek sustainable and environmentally friendly electrochemical energy sources for modern energy storage. Among potential candidates, aqueous Zn-ion batteries (AZIBs) are considered highly promising due to their safety, low cost, and eco-friendliness, especially compared to the safety hazards and economic challenges of popular lithium-ion batteries (LIBs). However, AZIBs face several challenges, including weak separator strength, inferior cathode performance, and the potential failure of the Zn anode due to issues like dendrite growth, passivation, and corrosion of pristine Zn in electrolytes. Among these challenges, metal anode failure is considered a significant factor in AZIB failure.<br>
To overcome this issue, various methods have been explored to achieve a highly stable Zn metal anode, such as designing novel structures, interfacial engineering, and introducing electrolyte additives. A 3D conductive host, e.g., zeolitic imidazolate framework-8 (ZIF8), is often considered an effective strategy as it provides a porous framework with an enlarged effective specific surface area, which can reduce local current densities, suppress dendrite formation, and buffer volume expansion during Zn plating.<br>
In Chapter 1, the demand for high-performance AZIBS and short terms of present zinc anode will be described and discussed.<br>
Chapter 2 is a literature review on artificial interlayers for functional AZIBS, background of AZIBS and functionality of interlayers will be discussed, how the dendrites and side reactions are suppressed, followed by a summary of some different interlayers from published articles. The reason for focusing on the anode coating layer is to decrease the contact area of electrolyte and anode to suppress the corrosion and dendrites formation as the Zn ions diffusion paths are not blocked even the coating layer can aid the transmission of Zn ions.<br>
Chapter 3 will describe the methodologies and techniques used in my project, and their purpose and criteria will be illustrated as well.<br>
Chapter 4 is a demonstration of ZIF8-supported g-C3N4(g-C3N4@ZIF8) as the coating layer in AZIB achieved a decent electrochemical performance and satisfying sustainability. g-C3N4 sustained by ZIF8 can modulate and adjust the Zn2+ flux, leading to a reduction in the corrosion area of the zinc anode in the water-based electrolyte. Additionally, with the low conductivity of g-C3N4 and ZIF8, Zn2+ can only migrate through the interlayer and deposit between the interlayer and Zn under the external electrical field. With this effective interlayer coating on the Zn anode, the symmetric cell can achieve 6,200 hours of cycling at 0.25 mA cm-2/0.25 mAh cm-2 and 1,000 hours of cycling at 5 mA cm-2/1 mAh cm-2, with remarkable rate performance that can reach 40 mA cm-2. When coupled with a flexible V2O5 nanopaper cathode, the full cell exhibits the ability to achieve over 1,000 stable cycles at a rate of 1A g-1. Hence, an artificial interlayer on the Zn anode can weaken corrosion and suppresses dendrite growth by evenly distributing ions and electrons, mitigating and slowing down the formation of the non-uniform anode surface. This design deaccelerates the growth speed and reduces the number of dendrites, enabling reversible Zn stripping/plating.<br><br>
Chapter 5 briefly summarizes previous chapters about research progress and experiment results and these work’s contribution to literature. It will also provide several suggestions for future work.</p>