Confined Electrodeposition in Localized Liquid Electrolyte Microzones for Microscale Metal Additive Manufacturing

Abstract Microscale metallic components are important for applications such as three-dimensional microinterconnects, thermal management, and microelectromechanical systems, where high material quality, structural precision, and process controllability are required. However, existing microscale metal additive manufacturing methods often involve tradeoffs among printing resolution, material density, material purity, and process complexity. Herein, we report a liquid-phase confined electrodeposition strategy for microscale metal additive manufacturing based on localized electrolyte delivery. A glass micropipette with a submicrometer opening delivers an electrolyte containing metal ions into a supporting electrolyte free of metal ions, thereby forming a localized electrolyte microzone near the substrate and enabling voxel-by-voxel localized metal deposition. The feature size of the printed deposits is regulated by the coupled effects of injection pressure and cathodic potential. By controlling the motion of the micropipette, various three-dimensional copper microstructures, including pillar arrays, cantilevers, helical arrays, hollow cylinders, and customized microscale patterns, are fabricated. Compositional, microstructural, and mechanical characterization shows that the printed copper structures exhibit compact polycrystalline microstructures, relatively high copper content, and stable mechanical response under microcompression. The strategy is further extended to platinum, silver, nickel, and a Ni–Mn alloy, demonstrating its adaptability to different metallic systems. This study establishes a liquid-phase confined electrochemical processing strategy for manufacturing microscale metallic components and offers practical guidelines for controlling feature size and structural quality.