Regulating Lithium Deposition via 3D Printed Current Collectors with Dual-Scale Roughness.

With the growing demand for future electric vehicles, mobile devices, and wearable electronics, lithium metal has emerged as a promising anode material, offering high theoretical capacity and low density. However, uncontrolled lithium dendrite growth and significant volume changes during cycling remain major challenges. In this study, to mitigate such challenges, we present a three-dimensional (3D) current collector design of a triply periodic minimal surface structure, fabricated using selective laser melting 3D printing of copper and modified through mechanical polishing to achieve dual-scale roughness. The resulting 3D current collector features a gyroid lattice with polished top surfaces and rough inner caverns, designed to induce preferential lithium nucleation within the caverns and promote confined growth. This gyroid structure increases the surface area and improves current density distribution, leading to highly improved Li deposition uniformity and reduced dendritic growth. As expected, cells using the 3D current collectors demonstrate a low nucleation overpotential, enhanced cycling stability, and improved rate performance. The manufacturing approach and structural design can be readily extended to other metal-based batteries, providing a versatile pathway for enhancing the performance and safety of metal electrode batteries.