Two-dimensional material composites for thermal management and energy storage
File(s)
Author(s)
Yao, Chengning
Type
Thesis
Abstract
Energy transition from fossil fuels to renewable energy sources using energy storage devices is a continuing trend and contributes to global CO2 reduction. However, existing energy storage technologies suffer from insufficient energy/power densities, energy loss and thermal issues during operation. 2D materials, with their exceptional electrical, thermal, and electrochemical properties, offer promising solutions as dielectric, electrode, and thermal interface materials to enhance energy and power densities and optimise energy efficiency. Despite their potential, the production of 2D materials remains largely confined to laboratory scales, necessitating the development of scalable manufacturing for industrial applications. This work aims to develop scalable processing of 2D materials, specifically h-BN and MXenes, and their composites using liquid phase exfoliation, to develop better energy storage devices. Using h-BN as dielectric additives for capacitors, the dielectric constant can achieve up to 17 compared to other printed nanomaterials (∼ 3-4), which could reduce the risk of devices being short-circuited and improve the device’s reliability. To maximise the energy efficiency of devices, h-BN is studied as a thermal filler for thermal interface materials to control device temperatures effectively. The addition of few-layer h-BN into cellulose increases the thermal conductivity of the composites at one order of magnitude higher, reaching ∼ 21.7 W m−1 K−1 and favouring more efficient heat transfer. Compared to insulating h-BN, MXenes show high electrical conductivity as promising electrode candidates for energy storage devices. Ti3C2Tx exhibits a metallic behaviour while Ti2CTx reveals a variable range hopping transport mechanism. The addition of electrically conducting Ti3C2Tx into the carbon-based electrode materials for supercapacitors enhances the device capacitance by 120 %. Through these investigations, the work demonstrates a foundation for deploying 2D materials in critical applications that can contribute to CO2 reduction by improving device reliability, energy efficiency and renewable energy storage capabilities.
Version
Open Access
Date Issued
2024-09-01
Date Awarded
2024-12-01
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Torrisi, Felice
Sponsor
Imperial College London
The European Union
Engineering and Physical Sciences Research Council
University of Cambridge
China Scholarship Council
Grant Number
CSC No. 202006210062
SAMOTHRACE-ECS00000022
EP/P02534X/2, EP/T005106/1, EP/R511547/1, EP/X026876/1
EP/P024947/1
EP/R00661X/1
Publisher Department
Chemistry
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)