Graphene oxide-based multifunctional composites for battery thermal management and EMI shielding applications

Abstract

Graphene has emerged as one of the most attractive materials for numerous applications due to its combination of superior mechanical strength, excellent electron and heat transfer capability, chemical and thermal stability, as well as other properties. To solve the practical issue of agglomeration and restacking of graphene sheets in bulky and composite forms, three-dimensional graphene networks (3DGNs) are engineered with high specific surface area, excellent conductivity and good mechanical strength. This research work focuses on developing novel graphene oxide (GO) - based multifunctional composites via a scalable wet extrusion method for battery thermal management and electromagnetic interference (EMI) shielding applications. In this thesis dissertation, researches of synthesis, properties and applications of graphene aerogels structures, phase change materials (PCMs), EMI shielding materials and battery thermal management technology have been reviewed. Subsequently, novel GO-based composites that can be applied in both battery thermal management and EMI shielding have been proposed. The work began with fabrication of graphene oxide aerogel beads (GOABs) by an improved wet-extruding method. The as-obtained beads were subjected to thermal annealing and absorption of liquid PCMs and collected for chemical, thermal and mechanical characterizations. The reduced GOABs (rGOABs) infiltrated with PCMs were integrated with thermally conductive silicone rubber for lithium ion battery (LIB) thermal management. The combination of rGOAB/PCMs and ceramic silicone rubber provides an effective and robust thermal management system for LIBs to avoid issues such as short-circuit, instability at high temperature and poor mechanical impact resistance which are rarely addressed in related works. In the meantime, reduced graphene oxide aerogel films (rGOAFs) were prepared in a similar manner with Ferromagnetic nanoparticles and carbon nanotubes (CNTs) and infiltrated with polymer for mechanical enhancement after thermal annealing. The lightweight mechanically strong rGOAFs show excellent EMI shielding performance which is mainly contributed by electromagnetic absorption.

Date of Award	2019
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology