Robust pure copper framework by extrusion 3D printing for advanced lithium metal anodes

Abstract

The application of lithium metal anodes is hindered by safety issues originating from unwanted Li dendritic growth. To address this issue, designing 3D porous Cu current collectors is an effective strategy to modify Li deposition behaviour. However, known fabrication processes for these porous collectors are usually complicated, expensive and non-scalable. There is also lack of investigation into their mechanical strength, which is an important factor for practical applications. Herein, we develop a simple, low-cost and scalable process to fabricate a robust Cu porous framework via extrusion 3D-printing. The 3D-printed Cu framework (3DP-Cu) can well maintain as-built microchannels between filaments even under a high compressive pressure of ∼1.4 MPa, enabling it to host massive Li deposition, prevent Li dendrite growth and mitigate large volume changes during charging/discharging. Therefore, 3DP-Cu achieves a significantly high areal capacity of 20 mA h cm⁻² with uniformly plated Li at a rate of 1 mA cm⁻². Moreover, stable Li plating/stripping behaviour is obtained in symmetric cells even at a high rate of 10 mA cm⁻², owing to the great ability to dissipate high local current densities efficiently by the porous network within filaments. Importantly, robocasting enables structural designs in any desired configurations and dimensions, thereby inspiring the fabrication of customized batteries.