Strontium-deficient SrxCoO2–CoO2 nanotubes as a high ampacity and high conductivity material

Abstract

Continuous miniaturization of electronics demands the development of interconnectors with high ampacity and high conductivity, which conventional conductors such as copper and gold cannot offer. Here we report the synthesis of Sr-deficient misfit Sr_xCoO₂–CoO₂ nanotubes by a novel crystal conversion method and investigate their electrical properties. Bulk Sr₆Co₅O₁₅ having a quasi-one-dimensional CoO₆ polyhedral structure (face-sharing octahedron and trigonal prismatic CoO₆ arranged in one-dimension) is converted to Sr_xCoO₂–CoO₂ nanotubes where CoO₂ adopts a two-dimensional edge-sharing CoO₂ layered structure in a basic hydrothermal process. Electrical properties measured on individual nanotubes demonstrate that these nanotubes are semiconducting with a conductivity of 1.28 × 10⁴ S cm⁻¹ and an ampacity of 10⁹ A cm⁻², which is the highest reported ampacity value to date of any inorganic oxide-based material. The nanotubes also show a breakdown power per unit channel length (P/L) of ∼38.3 W cm⁻¹, the highest among the regularly used interconnect materials. The above results demonstrate that Sr_xCoO₂–CoO₂ nanotubes are potential building blocks for high-power electronic applications.