Toward High Areal Energy and Power Density Electrode for Li-Ion Batteries via Optimized 3D Printing Approach.

High-energy and high-power-density lithium-ion batteries are promising energy storage systems for future portable electronics and electric vehicles. Here, three-dimensional (3D) patterned electrodes are created through the paste-extrusion-based 3D printing technique realizing a trade-off between high energy density and power density. The 3D electrodes possess several distinct merits over traditional flat thick electrodes, such as higher surface area, shorter ion transport path, and improved mechanical strength. Benefiting from these advantages, the 3D-printed thick electrodes present the higher specific capacity and improved cycling stability compared with those of the conventional thick electrodes. Upon comparison to the previous studies on 3D-printed electrodes, this study investigates the influence and optimization of 3D-printed LiFePO4 (LFP) electrodes with three different geometric shapes to achieve a high rate performance and long-term cycling stability. Accordingly, a series of 3D electrodes with different thickness were created, and an ultrathick (1500 μm) 3D-patterned electrode exhibits a high areal capacity of around 7.5 mA h cm-2, presenting remarkable value for state-of-the-art LFP cathodes. This work demonstrates patternable 3D printing as a potential strategy to fabricate thick electrodes toward high areal energy density and power density, which holds great promise for the future development of high-performance energy storage devices.