Advancing Electrophoretic Deposition for Multifunctional Structural Batteries

Abstract

This thesis presents a comprehensive study on the application of electrophoretic deposition (EPD) for the fabrication of multifunctional cathode electrodes in structural batteries. Structural batteries are emerging as a promising class of energy systems capable of combining mechanical and electrochemical functions in a single architecture. Such dual-purpose capability is of growing interest in sectors where lightweight design and space efficiency are critical, such as aerospace, automotive, and portable electronics. In this context, EPD was selected as the core fabrication method due to its advantages in process scalability, material versatility, and the ability to directly deposit active materials onto conductive structural substrates such as carbon fibres (CF). The study was divided into four major experimental paths: (1) enhancement of deposition quality through magnetic field assistance during the EPD process; (2) improvement of manufacturing efficiency via a redesigned high-throughput electrode holder; (3) extension of EPD application to electromagnetic interference (EMI) shielding by depositing Fe3O4-based composites; and (4) evaluation of electrochemical performance through controlled variation of reduced graphene oxide (rGO) content in LFP-based cathode formulations. While magnetic fields were not the main focus of this work, their selective application during deposition and drying stages proved effective in improving coating uniformity and reducing agglomeration under certain composition conditions. To explore multifunctionality beyond energy storage, Fe3O4 was introduced as a magnetic filler material in the EPD suspension to fabricate EMI shielding electrodes. Although EMI shielding effectiveness was not evaluated due to time limitations, the successful deposition of Fe3O4-based coatings on CF substrates supports the feasibility of EPD for future dual-functional applications. In parallel, the study evaluated electrochemical performance using half-cell pouch assemblies, tested through open circuit voltage (OCV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic cycling. The results indicated that moderate additions of rGO improve internal resistance and electrode kinetics, while excessive carbon additives adversely affect coating consistency and dispersion. Overall, this work demonstrates the adaptability and versatility of EPD in fabricating structural battery electrodes, while proposing pathways for integrating electromagnetic and electrochemical functionality. The results provide practical insights for future research and development of multifunctional power systems, laying a solid foundation for scalable, lightweight energy solutions in advanced engineering applications.