TY - JOUR
T1 - Sulfur Diffusion within Nitrogen-Doped Ordered Mesoporous Carbons Determined by in Situ X-ray Scattering
AU - Xia, Yanfeng
AU - Wang, Chao
AU - Li, Ruipeng
AU - Fukuto, Masafumi
AU - Vogt, Bryan D.
N1 - Funding Information:
The SAXS measurements used the Complex Materials Scattering (CMS/11-BM) beamline, operated by the National Synchrotron Light Source II and the Center for Functional Nanomaterials, which are U.S. Department of Energy (DOE) Office of Science User Facilities operated for the DOE Office of Science by Brookhaven National Laboratory under contract no. DE-SC0012704. The TEM data were obtained at the TEM facility at the Liquid Crystal Institute, Kent State University, supported by the Ohio Research Scholars Program Research Cluster on Surfaces in Advanced Materials. The authors thank Dr. Min Gao for assistance with TEM measurements, and Dr. Nikolov Zhorro for his assistance with the XPS measurements.
Funding Information:
*E-mail: [email protected]. ORCID Chao Wang: 0000-0002-5205-9771 Bryan D. Vogt: 0000-0003-1916-7145 Author Contributions The manuscript was written through contributions of all authors. Funding This work was supported by the National Science Foundation under grants nos. CBET-1159295 and CBET-1336057. Notes The authors declare no competing financial interest.
Funding Information:
The SAXS measurements used the Complex Materials Scattering (CMS/11-BM) beamline, operated by the National Synchrotron Light Source II and the Center for Functional Nanomaterials, which are U.S. Department of Energy (DOE) Office of Science User Facilities operated for the DOE Office of Science by Brookhaven National Laboratory under contract no. DE-SC0012704. The TEM data were obtained at the TEM facility at the Liquid Crystal Institute, Kent State University supported by the Ohio Research Scholars Program Research Cluster on Surfaces in Advanced Materials. The authors thank Dr. Min Gao for assistance with TEM measurements, and Dr. Nikolov Zhorro for his assistance with the XPS measurements.
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/7/31
Y1 - 2018/7/31
N2 - The low intrinsic conductivity of sulfur necessitates conductive additives, such as mesoporous carbons, to the cathode to enable high-performance metal-sulfur batteries. Simultaneous efforts to address polysulfide shuttling have introduced nitrogen-doped carbons to provide both conductivity and suppressed shuttling because of their strong interaction with sulfur. The strength of this interaction will impact the ability to fill the mesopores with sulfur via melt infusion. Here, we systematically investigate how nitrogen doping influences the rate that molten sulfur can infiltrate the mesopores and the overall extent of pore filling of highly ordered mesoporous doped carbons using in situ small angle X-ray scattering (SAXS). The similarity in electron density between molten sulfur and the soft carbon framework of the mesoporous material leads to a precipitous decrease in the scattered intensity associated with the ordered structure as voids are filled with sulfur. As the nitrogen doping increases from 1 to 20 at. %, the effective diffusivity of sulfur in the mesopores decreases by an order of magnitude (2.7 × 10-8 to 2.3 × 10-9 cm/s). The scattering becomes nearly invariant within 20 min of melt infiltration at 155 °C for all but the most doped carbon, which indicates that submicron-sized mesoporous carbon particles can be filled rapidly. Additionally, the nitrogen doping decreases the sulfur content that can be accommodated within the mesopores from 95% of the mesopores filled without doping to only 64% filled with 20 at. % N as determined by the residual scattering intensity. Sulfur does not crystallize within the mesopores of the nitrogen-doped carbons, which is further indicative of the strong interactions between the nitrogen species and sulfur that can inhibit polysulfide shuttling. In situ SAXS provides insights into the diffusion of sulfur in mesopores and how the surface chemistry of nitrogen-doped carbon appears to significantly hinder the infiltration by sulfur.
AB - The low intrinsic conductivity of sulfur necessitates conductive additives, such as mesoporous carbons, to the cathode to enable high-performance metal-sulfur batteries. Simultaneous efforts to address polysulfide shuttling have introduced nitrogen-doped carbons to provide both conductivity and suppressed shuttling because of their strong interaction with sulfur. The strength of this interaction will impact the ability to fill the mesopores with sulfur via melt infusion. Here, we systematically investigate how nitrogen doping influences the rate that molten sulfur can infiltrate the mesopores and the overall extent of pore filling of highly ordered mesoporous doped carbons using in situ small angle X-ray scattering (SAXS). The similarity in electron density between molten sulfur and the soft carbon framework of the mesoporous material leads to a precipitous decrease in the scattered intensity associated with the ordered structure as voids are filled with sulfur. As the nitrogen doping increases from 1 to 20 at. %, the effective diffusivity of sulfur in the mesopores decreases by an order of magnitude (2.7 × 10-8 to 2.3 × 10-9 cm/s). The scattering becomes nearly invariant within 20 min of melt infiltration at 155 °C for all but the most doped carbon, which indicates that submicron-sized mesoporous carbon particles can be filled rapidly. Additionally, the nitrogen doping decreases the sulfur content that can be accommodated within the mesopores from 95% of the mesopores filled without doping to only 64% filled with 20 at. % N as determined by the residual scattering intensity. Sulfur does not crystallize within the mesopores of the nitrogen-doped carbons, which is further indicative of the strong interactions between the nitrogen species and sulfur that can inhibit polysulfide shuttling. In situ SAXS provides insights into the diffusion of sulfur in mesopores and how the surface chemistry of nitrogen-doped carbon appears to significantly hinder the infiltration by sulfur.
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U2 - 10.1021/acs.langmuir.8b01375
DO - 10.1021/acs.langmuir.8b01375
M3 - Article
C2 - 29975064
AN - SCOPUS:85049795422
SN - 0743-7463
VL - 34
SP - 8767
EP - 8776
JO - Langmuir
JF - Langmuir
IS - 30
ER -