The global energy infrastructure is undergoing a drastic transformation towards renewable energy, posing huge challenges on the energy materials research, development and manufacturing. Additive manufacturing has shown its promise to change the way how future energy system can be designed and delivered. It offers capability in manufacturing complex 3D structures, with near‐complete design freedom and high sustainability due to minimal use of materials and toxic chemicals. Recent literatures have reported that additive manufacturing could unlock the evolution of energy materials and chemistries with unprecedented performance in the way that could never be achieved by conventional manufacturing techniques. This comprehensive review will fill the gap in communicating on recent breakthroughs in additive manufacturing for energy material and device applications. It will underpin the discoveries on what 3D functional energy structures can be created without design constraints, which bespoke energy materials could be additively manufactured with customised solutions, and how the additively manufactured devices could be integrated into energy systems. This review will also highlight emerging and important applications in energy additive manufacturing, including fuel cells, batteries, hydrogen, solar cell as well as carbon capture and storage.

In recent years, the use of additive manufacturing (AM) has been demonstrated in the fabrication of components in polymer electrolyte membrane fuel cell, solid oxide fuel cell (SOFC), microbial fuel cell (MFC) and laminar flow-based fuel cell (LFFC). Various AM technologies have been successfully demonstrated in fuel cell manufacturing include material extrusion, powder bed fusion, vat photopolymerization and binder jetting. One of the unique advantages of AM is the ability to handle sophisticated design with features ranging from macro to micro scales, which are inaccessible by conventional manufacturing technologies. Well-designed complex 3D structures were reported to have the potential for increasing the performance of fuel cells. Therefore, AM presents itself as a promising fabrication method to promote the development of fuel cells. Besides, AM also showed its specialty in time-saving, flexibility, and on-demand manufacturability in the fabrication of fuel cell components. In spite of the prospects of AM in fuel cells, more studies and researches are required to overcome challenges, such as availability of material, manufacturing quality, and the costs. This review focuses on the advantages and applications of additive manufacturing that enable improvement in fuel cell performance. The critical challenges and directions for future development are also highlighted.

The electronic industry has room for improvement in adopting cleaner strategies, both in production processes (often energy-intensive and polluting) and in waste management. Many small components like security tags are routinely disposed of via general waste, which could be reduced adopting biodegradable polymers. In this work, a method for selective deposition of metallic micro-tracks on polycaprolactone (PCL) for circuitry integration is presented. The polymer is biodegradable, flexible, suitable for 3D printing, and can be obtained from sustainable sources. Photoreduction of Ag ions was used to generate seeds for subsequent selective electroless copper (Cu) plating in a process that avoids common but undesirable compounds such as cyanides and palladium. Two different photopatterning methods were successfully used to achieve selective Cu plating: flood exposure with a 460 nm light-emitting diode (LED) and direct laser writing (DLW) using a 405 nm laser, achieving 47 ± 11 μm wide tracks. The deposition of uniform Cu layers on PCL substrates is demonstrated, with thicknesses of up to 14 μm and electrical conductivities of up to 2.06 × 107 S m−1, which is near the conductivity of bulk Cu (5.89 × 107 S m−1). Cu-plated interconnects were demonstrated to be fully functional for powering a 5 SMD LEDs circuit. Furthermore, DLW enabled the interconnect manufacturing on an uneven substrate. This method is flexible, selective, low-cost, vacuum-free and of minimized environmental impact, and it provides a new route towards the manufacturing of biodegradable electronics.

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