Stable CoO${}_2$ Nanoscrolls With Outstanding Electrical Properties

Abstract

Layered CoO${}_2$ is of great interest for its promising properties but is meta-stable in its bulk form. CoO${}_2$ was synthesized by converting the quasi-one-dimensional crystal structure of bulk Ca${}_3$Co${}_2$O${}_6$ via a hydrothermal treatment. The resulting nanostructures were predominantly nanoscrolls with very thin walls, which exhibit long-term stability. A detailed structural investigation reveals that the CoO${}_2$ is found to crystallize in monoclinic form, similar to the related CaCoO${}_2$-CoO${}_2$ misfit structure. Individual nanoscrolls are characterized electrically and show a p-type semiconducting nature with a high current-carrying capacity of 4$\cdot$10${}^5$ A cm${}^{-2}$ and an extremely high breakdown voltage of up to 270 kV/cm. The results demonstrate the possibility to stabilize meta-stable materials in low-dimensional forms and a promising application of the nanoscrolls as interconnect in high-voltage electronic circuitry.