title: Synthesis of hollow cobalt oxide nanopowders by a salt-assisted spray pyrolysis process applying nanoscale Kirkendall diffusion and their electrochemical properties.
abstract: A new concept for preparing hollow metal oxide nanopowders by salt-assisted spray pyrolysis applying nanoscale Kirkendall diffusion is introduced. The composite powders of metal oxide and indecomposable metal salt are prepared by spray pyrolysis. Post-treatment under a reducing atmosphere and subsequent washing using distilled water produce aggregation-free metal nanopowders. The metal nanopowders are then transformed into metal oxide hollow nanopowders by nanoscale Kirkendall diffusion. Co3O4 hollow nanopowders are prepared as first target materials. A cobalt oxide-NaCl composite powder prepared by spray pyrolysis transforms into several Co3O4 hollow nanopowders by several treatment processes. The discharge capacities of the Co3O4 nanopowders with filled and hollow structures at a current density of 1 A g(-1) for the 150th cycle are 605 and 775 mA h g(-1), respectively. The hollow structure formed by nanoscale Kirkendall diffusion improves the lithium-ion storage properties of Co3O4 nanopowders.
authors.affiliation: Department of Materials Science and Engineering, Korea University, Anam-dong, Seongbuk-gu, Seoul 136-713, Korea. yckang@korea.ac.kr.
authors.forename: Hyeon Seok
authors.initials: HS
authors.lastname: Ju
authors.forename: Jung Sang
authors.initials: JS
authors.lastname: Cho
authors.forename: Jong Hwa
authors.initials: JH
authors.lastname: Kim
authors.forename: Yun Ju
authors.initials: YJ
authors.lastname: Choi
authors.forename: Yun Chan
authors.initials: YC
authors.lastname: Kang