Efficient Fabrication of Ultralight YBa2Cu3O7−x Superconductors with Programmable Shape and Structure

Abstract Superconducting YBa 2 Cu 3 O 7− x (YBCO) bulks have demonstrated promising applications in quasi‐permanent magnets, levitation, etc. Recently, the applications of bulk superconductors have been proposed, such as in portable, ultralight superconducting devices. These applications require bulk superconductors with lightweight, complex morphology, and good processability. However, the traditional fabrication method of YBCO bulks requires prolonged supplemental oxygenation and produces limited geometries with many randomly distributed cracks. This, combined with the inherent brittleness of the ceramic material, seriously impedes its wide application. In this study, a YBCO bulk with a multiscale hierarchical geometric configuration is constructed by a direct‐ink‐writing‐based 3D‐printing process. The 3D‐printed YBCO green bodies exhibit a robust structure after directional freezing, which promotes intimate contact between the precursor particles in the deposited layers. This technology offers the advantage of a low shrinkage of 13.6 vol% after sintering at 920 °C. The 3D‐printed bulks show lightweight, highly crystalline, and good electromagnetic properties compared with those produced by traditional cold‐pressed sintering. Importantly, the multilevel void structure with a large specific surface area significantly reduces the oxygenation time and retains superconductivity. The proposed 3D‐printing process can be adopted for the industrial production of superconducting bulk with complex geometries for novel applications.