Three-dimensional printed carbon-based microbatteries: progress on technologies, materials and applications

Next-generation wearable and portable devices require rechargeable microbatteries to provide energy storage. Three-dimensional (3D) printing, with its ability to build geometrically complex 3D structures, enables the manufacture of microbatteries of different sizes and shapes, and with high energy and power densities. Lightweight carbon materials have a great advantage over other porous metals as electrode materials for rechargeable batteries, because of their large specific surface area, superior electrical conductivity and high chemical stability. In recent years, a variety of rechargeable microbatteries of different types have been successfully printed using carbon-based inks. To optimize their electrochemical performance and extend their potential applications, it is important to analyze the design principles with respect to the 3D printing technique, printable carbon materials and promising applications. This paper provides a perspective on recent progress in the four major 3D printing techniques, elaborates on conductive carbon materials in addressing the challenging issues of 3D printed microbatteries, and summarizes their applications in a number of energy storage devices that integrate with wearable electronics. Current challenges and future opportunities for carbon-based microbattery fabrication by 3D printing techniques are discussed.