3D printing of advanced functional materials for sustainable energy systems

Constant and secure energy supply plays a critical role in the stable development of one society and economy. The Paris agreement signed in 2015 by 174 countries has also acknowledged the importance of boosting energy efficiency and developing sustainable energy technologies for mitigating global warming and reducing other effects caused by the climate change. Among all advances, adopting new manufacturing methods for energy systems has been considered as a way to contribute to such a development. Additive manufacturing, also known as 3D printing (3DP), has recently emerged as a practical strategy for optimizing fabrication process, innovating the design and enhancing energy systems´ performance. By covering research and innovation from starting materials´ formulation, printers´ development to complex structural design and system integration, 3DP technology is expected to generate a variety of new customized products with controlled structures and embedded functionalities. Despite the use of 3DP in energy systems has great promises for future challenges, this technology is not developed yet and a thoughtful analysis is thus needed to provide general criteria to link 3DP technology and the energy technology. As a starting point, current research shows the significance of converting advanced functional energy materials into 3DP-processable compounds that are designed to achieve tailored microstructures and 3D complex shape. Subsequently, this work is designed to develop 3D printable materials with devised microstructures and complex geometries for potential energy applications. To explain it more into detail, the experimental work is based on 3D printed piezoelectric ceramic materials for mechanical energy harvesting systems. As one of the most interesting and representative 3DP techniques, fuse deposition modeling (FDM) is selected due to its capability of producing high-resolution objects with low-cost and low energy consumption. The experimental approach included material synthesis (e.g. the fabrication of BaTiO3, the preparation of spinning solution, the electrospinning and the calcination process), BaTiO3-PVDF-NMP printing pastes preparation, 3D printing and finally some post-processing procedures. Characterization results show that barium titanate microfibers (BTMFs) with high-yield fabrication and consistent size are successfully produced. Simple CAD designed structures with controllable highly-oriented BTMFs were manufactured by FDM. In addition, an enhanced dielectric property is observed in the 3D printed material. At the end, a general study of the business analysis of the prepared functional materials and its possible business development plan was conducted. In conclusion, this master thesis summarizes the progress of energy technologies processed by 3DP and provides new perspectives in the manufacturing of high-performance, flexible piezoelectric hybrid materials that have promising applications in energy harvesting and sensing technologies.