Recent advances in materials science and nanoscience are reshaping sustainable technologies through innovative materials and novel device architectures. However, key challenges remain in translating these advances into practical device applications. To address this, this thesis focuses on the design and integration of multifunctional nanomaterials into advanced devices for energy harvesting, energy storage, and electromagnetic interference (EMI) shielding.
The first section of this thesis mainly explores energy harvesting through triboelectric nanogenerators (TENGs) for self-powered applications. We first explored multi-material three-dimensional (3D) printing for the one-step fabrication of TENGs for mechanical-to-electrical energy conversion.  These TENGs are further utilised as smart floor tiles that simultaneously harvest energy from footsteps while operating as a real-time motion/security monitoring device. Furthermore, we investigated the Ti2AlC MAX (M=Ti, A=Al, X=C) phase to fabricate a MAX-polymer composite electrode for TENG. This TENG is then integrated with an electrochemical nitrate reduction system that can harness the wasted low-frequency vibrational energy for green ammonia production. This electrode exhibits enhanced performance compared to the pristine polymer-based TENG. This demonstrates the application of tactile sensors and a self-powered energy source at ambient conditions.
The second section of this thesis explores the energy storage system, with a focus on supercapacitor technologies. We explored a scalable and cost-effective fused deposition modelling (FDM) 3D-printing technique for fabricating a supercapacitor electrode. To overcome the high polymer content that affects the electrochemical activity of carbon nanomaterials, we modified the electrode surface using the deposition of two-dimensional (2D) materials. We utilised a tungsten disulfide-modified 3D-printed carbon electrode as the supercapacitor electrode, demonstrating enhanced charge storage in 3D-printed solid-state supercapacitors. Furthermore, we investigated an MXene and polyaniline (PANI) modified 3D-printed electrode to fabricate an asymmetric supercapacitor, which expanded the operating voltage window and energy density to power small electronic components in a standalone configuration.
The third section explores EMI shielding using 3D-printed nanocarbon composites. The shielding effectiveness of conductive fillers, such as carbon nanotubes (CNTs) and carbon black (CB), was systematically compared. The shielding capabilities of these 3D-printed nanocarbon composites are further enhanced by the electrochemical deposition of PANI. These findings highlight the potential of PANI@3D-printed composites as sustainable alternatives to conventional metal-based shields.
Collectively, this thesis demonstrates that novel and multifunctional nanomaterials can be rationally engineered to enable next-generation, high-performance energy devices. These are achieved through the integration of various techniques, including electrochemical synthesis and additive manufacturing, which enable control over interfacial functionality. Together, these advances in energy harvesting, storage, and EMI shielding push us one step closer to building advanced self-sustaining systems.