Metal-organic framework-based triboelectric nanogenerators

Thesis

The growing demand for sensors in modern technologies has increased the necessity for efficient and sustainable energy harvesting technologies. Triboelectric nanogenerators (TENGs), which operate based on contact electrification and electrostatic induction, have garnered significant attention over the past decade. However, the limited selection of high-performance materials remains a key challenge in advancing TENG technology. Metal-organic frameworks (MOFs), with their exceptional tuneability in structure and properties, present excellent potential to develop next-generation TENG materials with enhanced triboelectric output. Beyond improving performance, MOFs provide a unique platform for studying the underlying charge transfer mechanisms. In this integrated thesis, the fundamental principles of TENG technology and recent advances in MOF-based TENGs are introduced in Chapter 1 and 2, followed by an overview of triboelectric testing setups and characterisation techniques in Chapter 3.

Chapter 4 to 7 explore different approaches to material and structural design to enhance TENG performance. Specifically, Chapter 4 examines the influence of MOF topology on triboelectric output, while Chapter 5 focuses on the effect of ligand functionalisation. The mechanisms behind these improvements are revealed by nano-scale chemical and mechanical characterisations, dielectric measurements, and computational simulations. Chapter 6 introduces a detailed investigation of a noncontact rotational TENG design, incorporating a fluorinated MOF to extend the practical applications of MOF-based TENGs. Chapter 7 explores a surface modification strategy for conventional polymer materials, providing deeper insights into the charge transfer mechanisms through various proposed models.

Overall, this thesis aims to facilitate the design of high-performance TENG devices through a materials-driven approach while expanding their potential applications. The findings are critically summarised in Chapter 8, with a discussion on future research directions in the field of MOF-based TENGs.

Authors: Ye, J

• DOI: 10.5287/ora-gpbjyn4r7
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: nanocomposites; metal-organic frameworks; triboelectric nanogenerators; energy harvesting
• Subjects: Engineering; Materials science