High-speed electrolyte jet 3D printing of ultrasmooth and robust Cu microelectrodes

Abstract

Electrochemical 3D printing technology built on computer numerical control platforms has enabled multi-dimensional and multi-scale manufacturing of various metal materials through layered electrochemical deposition. Compared to thermal 3D printing technology, electrolyte meniscus-confined 3D printing can manufacture Cu microstructures with fewer defects and smoother surfaces. In the meantime, it is still susceptible to unstable liquid–solid-air interfaces, low deposition rates, and limited printing geometry. This work combined jet electrochemical deposition with a portable 3-axis platform to develop a cyclic high-speed electrolyte jet (HSEJ) 3D printer. It offers a faster deposition rate of 53.4 µm/h when printing ultrasmooth Cu microelectrodes with surface average roughness down to 1.1 nm and microhardness of 3.3 GPa which is much higher than the best result of 2.4 GPa obtained by the other ECD methods. It is identified that the fluctuation of cathode current density plays a crucial role in defining the nucleation morphology on the Cu surface, while the cathode current efficiency is a reliable indicator to assess the deposition localization by reflecting the variation of diffusion percentage. HSEJ 3D printing provides a sustainable pathway for the facile recycling of waste cables into high-grade metal microelectronics with controllable surface morphology and 3D dimensions. Graphical Abstract