3D printing of structured electrodes for rechargeable batteries

Structural design, shape fabrication, and device assembly are the key factors to be considered in the design of high-performance rechargeable batteries (REBs). A well-designed structure can effectively improve the utilization of internal space and electrode surface area and consequently promote the electrochemical performance of REBs. Three-dimensional (3D) printing is an emerging advanced manufacturing technology that can be used to fabricate energy storage devices from the nanoscale to the macroscale. Different from traditional techniques, 3D printing can be used to fabricate well-designed 3D structured batteries, yielding higher performance and better space utilization due to the increased surface area and hierarchical 3D structures of the electrodes/electrolytes. Numerous 3D printed electrodes and electrolytes for REBs have been reported in recent years. Nevertheless, the structural characteristics of 3D printed electrodes/electrolytes and the regulatory effects of 3D structures on the performance have been rarely discussed in earlier reviews. Therefore, it is very important to comprehensively summarize and understand the features of various 3D printed electrode/electrolyte structures and their impact on the performance for further structural design, technological development, and battery optimization. In this review, basic materials, technologies, and structures are described to provide a fundamental understanding on 3D printed batteries. Electrodes or electrolytes with 3D printed structures, such as film, interdigitated, and framework structures, are summarized based on the characteristics of their structures as well as performance. Optimization strategies for batteries are comprehensively discussed. Some unique challenges and critical directions in 3D printed batteries are subsequently discussed. More importantly, this review offers a unique insight into how to use 3D printing technology from the perspective of structural design and optimization to fabricate efficient electrodes/electrolytes over multiple length scales for fabricating the next generation of high-performance energy storage devices.