標題: Prior vacuuming for supercritical fluid synthesis of SnO2/graphene nanocomposites with superior electrochemical Li+ storage performance
作者: Xie, Jian-De
Li, Hui-Ying
Umesh, Bharath
Lee, Tai-Chou
Chang, Jeng-Kuei
Gandomi, Yasser Ashraf
材料科學與工程學系
Department of Materials Science and Engineering
關鍵字: Supercritical CO2;SnO2 nanoparticles;Composites;Anode;Li-ion battery
公開日期: 1-Dec-2018
摘要: 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 SO2 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 similar to 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). (C) 2018 Elsevier Ltd. All rights reserved.
URI: http://dx.doi.org/10.1016/j.electacta.2018.09.084
http://hdl.handle.net/11536/148433
ISSN: 0013-4686
DOI: 10.1016/j.electacta.2018.09.084
期刊: ELECTROCHIMICA ACTA
Volume: 292
起始頁: 951
結束頁: 959
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