Get access

Kilogram-Scale Production of SnO2 Yolk–Shell Powders by a Spray-Drying Process Using Dextrin as Carbon Source and Drying Additive

Authors

  • Seung Ho Choi,

    1. Department of Chemical Engineering, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701 (Korea), Fax: (+82) 2-458-3504
    Search for more papers by this author
  • Prof. Yun Chan Kang

    Corresponding author
    1. Department of Chemical Engineering, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701 (Korea), Fax: (+82) 2-458-3504
    • Department of Chemical Engineering, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701 (Korea), Fax: (+82) 2-458-3504===

    Search for more papers by this author

Abstract

A simple and general method for the large-scale production of yolk–shell powders with various compositions by a spray-drying process is reported. Metal salt/dextrin composite powders with a spherical and dense structure were obtained by spray drying and transformed into yolk–shell powders by simple combustion in air. Dextrin plays a key role in the preparation of precursor powders for fabricating yolk–shell powders by spray drying. Droplets containing metal salts and dextrin show good drying characteristics even in a severe environment of high humidity. Sucrose, glucose, and polyvinylpyrrolidone are widely used as carbon sources in the preparation of metal oxide/carbon composite powders; however, they are not appropriate for large-scale spray-drying processes because of their caramelization properties and adherence to the surface of the spray dryer. SnO2 yolk–shell powders were studied as the first target material in the spray-drying process. Combustion of tin oxalate/dextrin composite powders at 600 °C in air produced single-shelled SnO2 yolk–shell powders with the configuration SnO2@void@SnO2. The SnO2 yolk–shell powders prepared by the simple spray-drying process showed superior electrochemical properties, even at high current densities. The discharge capacities of the SnO2 yolk–shell powders at a current density of 2000 mA g−1 were 645 and 570 mA h g−1 for the second and 100th cycles, respectively; the corresponding capacity retention measured for the second cycle was 88 %.

Ancillary