L.L. Zhang, J.Q. Qin, P. Das, S. Wang, T.S. Bai, F. Zhou*, M.B. Wu* and Z.-S. Wu *

Advanced Materials, 2024, Accepted.

3D printing technology with enhanced fidelity can achieve multiple functionalities and boost electrochemical performance of customizable planar micro-supercapacitors (MSCs), however, precise structural control of additive-free graphene-based macro-assembly electrode for monolithic integrated MSCs (MIMSCs) remain challenging. Here, we report the large-scale 3D printing fabrication of customizable planar MIMSCs utilizing additive-free, high-quality electrochemically exfoliated graphene inks, which is not required the conventional cryogenic assistance during the printing process and any post-processing reduction. The resulting MSCs reveal an extremely small engineering footprint of 0.025 cm2, exceptionally high areal capacitance of 4900 mF cm−2, volumetric capacitance of 195.6 F cm−3, areal energy density of 2.1 mWh cm-2, and unprecedented volumetric energy density of 23 mWh cm−3 for a single cell, surpassing most previously reported 3D printed MSCs. We further demonstrate the 3D printed MIMSC pack, with the maximum areal cell count density of 16 cell cm-2, achieve the highest output voltage of 192.5 V and the largest output voltage per unit area of 56 V cm−2 up to date. This work presents an innovative solution for processing high-performance additive-free graphene ink and realizing the large-scale production of 3D printed MIMSCs for planar energy storage.