Morphological control of cuprate superconductors using sea sponges as templates

Functional porous superconducting sponges, consisting of YBa₂Cu₃O₆₊ (YBCO) and Bi₂Sr₂CaCu₂O₈₊ (BSCCO), were created by biotemplating with natural sea sponges. Naturally occurring calcium in the spongin fibers was utilized to dope YBCO and to form BSCCO without adding any external calcium source. The sample morphology was confirmed with scanning electron microscopy, and the sample composition was confirmed with energy-dispersive X-ray spectroscopy, powder electron diffraction and high-resolution transmission electron microscopy. The YBCO sponge exhibited a critical temperature (T _c) of approximately 70 K, and the BSCCO sponge showed a T _c of 77 K. This proof-of-concept study demonstrates the feasibility of using sea sponges as a greener, more sustainable template for superconductor synthesis.