Synthesis of porous high-temperature superconductors via a melamine formaldehyde sacrificial template

Abstract

Nanostructured high-temperature superconductors YBa₂Cu₃O_6+δ and Bi₂Sr₂CaCu₂O_8+δ were synthesised using a melamine formaldehyde sponge as a sacrificial template, via three solution-based approaches. In the case of YBa₂Cu₃O_6+δ, a modified Pechini method produced a material with a superconducting transition at 92 K and a specific surface area of 4.22 m² g⁻¹. Further analysis with Hg porosimetry determined that the sponge exhibited a porosity of 82%. In the case of Bi₂Sr₂CaCu₂O_8+δ, this method produced a material that exhibited superconductivity at 86 K with a specific surface area of 9.62 m² g⁻¹. Hg-porosimetry determined that the BSCCO sponge exhibited a porosity of 78%.