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  4. Synergy of Graphene Nanoribbons and Graphene Sheets for High-Rate Lithium-Sulfur Batteries

Synergy of Graphene Nanoribbons and Graphene Sheets for High-Rate Lithium-Sulfur Batteries

File(s)
An_cornell_0058O_10995.pdf (4.62 MB)
Permanent Link(s)
https://doi.org/10.7298/kybf-mb54
https://hdl.handle.net/1813/103005
Collections
Cornell Theses and Dissertations
Author
An, Meichun
Abstract

According to the increasing demands for shortening the battery charging time, high current rate (C-rate) performances become more significant in practical applications. With a higher theoretical capacity, lithium-sulfur batteries are treated as promising candidates for the next-generation batteries. In this work, the utilization of graphene nanoribbons (GNRs) exhibits the benefits in conductivity and other electrochemical performances, especially for high-rate applications. With air-controlled electrospray as the method, carbon encapsulated sulfur particles, poly(acrylic acid), reduced graphene oxide (rGO) sheets, and GNRs are mixed and directly deposited onto the carbon coated aluminum collector, to employ as the cathode. The scanning electron microscopy (SEM) imaging exhibits that the two-dimensional structure of GNRs helps construct inter-connected networks. This improved structure of cathode can increase the electroconductivity, confirmed by the electrochemical impedance spectroscopy (EIS), and modify the porosity, indicated through pore size distribution profiles. In this way, the polysulfides can be more efficiently trapped and utilized, realizing the promising behavior with faster charge transfer. In terms of the cycling performance at 0.2 C, the batteries with GNRs can perform 18% higher in capacity than those without GNRs, without decreasing the charge retention. According to the rate-capability tests, systems with GNRs can achieve enhanced performance, especially at high C-rates. At 2 C, with 80 wt % of graphene-based materials as GNRs, the capacity can be increased by 74% compared with that of the system without GNRs. Accordingly, the results testify the synergy of GNRs and rGO sheets in Li-S batteries.

Description
80 pages
Date Issued
2020-08
Keywords
air-controlled electrospray
•
graphene
•
graphene nanoribbons
•
graphene oxide nanoribbons
•
high rate
•
lithium-sulfur battery
Committee Chair
Joo, Yong L.
Committee Member
Hanrath, Tobias
Suntivich, Jin
Degree Discipline
Chemical Engineering
Degree Name
M.S., Chemical Engineering
Degree Level
Master of Science
Rights
Attribution-NonCommercial-ShareAlike 4.0 International
Rights URI
https://creativecommons.org/licenses/by-nc-sa/4.0/
Type
dissertation or thesis
Link(s) to Catalog Record
https://catalog.library.cornell.edu/catalog/13277861

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