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

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 SrxCoO2–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 SrxCoO2–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 SrxCoO2–CoO2 nanotubes are potential building blocks for high-power electronic applications.
Prof. L.S.P. would like to acknowledge Science and Engineering Research Board under the Department of Science and Technology (DST-SERB), Government of India for funding (EMR/2016/003594). K.S.R. acknowledges the Department of Chemistry, Department of Physics and Department of Materials Engineering and Materials Science, Indian Institute of Technology (IIT) Bombay and Industrial Research and Consultancy Center (IRCC), Sophisticated Analytical Instrument Facility (SAIF), Centre of Excellence in Nanoelectronics (CEN) IIT Bombay and Fund for Improvement of S&T Infrastructure (FIST) for all the facilities provided. K.S.R. sincerely thanks Gayatri Vaidya at IIT Bombay for helpful assistance and discussion about the fabrication process. S.H. and R.A. acknowledge funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 889546 and from the Spanish MICINN (project grant PID2019-104739GB-100/AEI/10.13039/501100011033). R. A. acknowledges funding from the Government of Aragon (project DGA E13-20R) and European Union H2020 program “ESTEEM3” (823717).