Abstract
The thesis conducts a systematic analysis of the critical challenges in energy storage systems, particularly focusing on inefficiency and sustainability issues. The research elucidates the pivotal role of electrochemical energy storage in facilitating global energy transition, with special emphasis on aqueous zinc-ion batteries(AZIBs). This technology has emerged as a viable electrochemical energy storage solution, demonstrating superior safety profiles, economic viability, and enhanced environmental compatibility. However, their practical implementation is hindered by fundamental challenges arising from thermodynamic instability and irregular potential distribution during zinc deposition. To address these limitations, an innovative hybrid organic inorganic solid-to-hydrogel electrolyte interface through in-situ coordination reactions and self-regulating processes is developed. This engineered interface creates uniform ionic diffusion pathways via molecular bridges, enhancing ion transport kinetics. Moreover, the novel system demonstrates unique self-regenerative capabilities through continuous inorganic component reorganization, extending its protective functionality while simultaneously improving mechanical robustness as evidenced by Young's modulus measurements. The adaptive interface effectively suppresses both corrosion and passivation phenomena while establishing well-ordered potential gradients within the Helmholtz layer. Consequently, Zn²⁺ ions undergo controlled deposition, forming dense, finely structured, and homogeneous nucleation patterns., effectively suppressing dendrites and side reactions while enhancing mechanical strength. The modified Zn electrodes enable asymmetric cells to achieve 3000-hour stability (1 mA cm⁻², 0.5 mAh cm⁻²) and maintain 99.6% Coulombic efficiency over 1200 cycles.Building on the insights from the interface construction, another study is designed to investigate the stabilization of zinc anodes using a novel electrolyte additive featuring an in-situ reduction mechanism. Experimental validation confirmed that the introduced electrolyte additive preferentially adsorbs onto the zinc anode surface, where it operates through a dual mechanism combining reduction and coordination. This mechanism also facilitates the formation of a hydrophobic organic-inorganic solid electrolyte interfacial, which provides enhanced protection and stability to the zinc anode. Unlike conventional approaches to electrolyte engineering, this additive not only creates an optimal hydrogen bond environment but also integrates the synergistic effects of in-situ oxidation and coordination to efficiently regulate the zinc anode. This multifunctional mechanism improves the utilization efficiency of the additive, offering a more effective strategy for mitigating usual challenges such as dendrite growth and side reactions. The innovative electrolyte demonstrates good cycling stability across multiple configurations: 3000 hours in symmetric cells (1 mA cm-², 0.5 mAh cm⁻²), 87.5% retention after 2,000 cycles in Zn||MnO₂ full cells, and 90% retention through 600 cycles in high-loading pouch cells. A core innovation of this work lies in the exploration of a unique anode protection mechanism to fundamentally address zinc dendrite growth and interfacial side reactions.
By designing novel composite interfacial layers or electrolyte additives, it is targeted that the achievement of laboratory-level advanced anode stability, which is critical for high-performance AZIBs. These distinctive approaches not only improve cycling durability but also provide new insights into zinc metal stabilization strategies. By synergistically tackling these challenges—through cost-effective materials and pioneering anode protection, this research seeks to accelerate the commercialization of scalable, eco-friendly energy storage systems. The findings are expected to contribute both fundamentally and practically to the development of next-generation AZIBs, ultimately supporting a sustainable and market-viable energy future.
| Date of Award | 15 Jul 2026 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Shahid Iqbal (Supervisor), Ibrahim Khan (Supervisor) & Hui YANG (Supervisor) |