Prior vacuuming for supercritical fluid synthesis of SnO2/graphene nanocomposites with superior electrochemical Li+ storage performance

Jian De Xie*, Hui Ying Li, Bharath Umesh, Tai Chou Lee, Jeng-Kuei Chang, Yasser Ashraf Gandomi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Supercritical CO2 (SCCO2) fluid, exhibiting gas-like diffusivity, extremely low viscosity, and near-zero surface tension, is used to synthesize uniformly dispersed and tightly anchored SnO2 nanoparticles (a 3-nm diameter was achieved) on graphene nanosheets (GNSs). Usually, the conventional synthesis processes (in the absence of SCCO2) results in aggregated SnO2 clusters; whereas the technique described in this work eliminates this limitation. This study reveals the significance of two crucial factors (the SCCO2 pressure (i.e., fluid density) and the degassing step (i.e., vacuuming stage) in autoclave before injecting CO2) on the uniform distribution of the synthesized SnO2 nanoparticles on GNSs. Increasing the pressure leads to an increase in SCCO2 density (and viscosity), suppressing the transport of SnO2 precursors throughout the sample. On the other hand, vacuuming the autoclave before injecting CO2 improves the uniformity of SnO2 particle distributions. To assess the electrochemical performance of the synthesized nanoparticles, the specific capacity, rate capability, and cyclic stability were determined for various samples. A capacity of ∼787 mAh g−1 at 100 mA g−1 was achieved for an optimal configuration of the SnO2/GNS electrodes. The capacity retention was 60% when the charge‒discharge rate increased to 6000 mA g−1.

Original languageEnglish
Pages (from-to)951-959
Number of pages9
JournalElectrochimica Acta
StatePublished - 1 Dec 2018


  • Anode
  • Composites
  • Li-ion battery
  • SnO nanoparticles
  • Supercritical CO

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