Compatibility of Graphite Materials with Block Copolymer Electrolyte for Lithium Batteries

Graphite has good lifetime and rate capability in liquid electrolyte-based batteries and supercapacitors. Meanwhile, the polymer electrolyte have been considered as a promising technology for battery applications for its safety and flexible cell configuration design which sat...

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Other Authors: Zhou, Sifei (authoraut)
Format: Others
Language:English
English
Published: Florida State University
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Online Access:http://purl.flvc.org/fsu/fd/FSU_FA2016_Zhou_fsu_0071N_13603
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spelling ndltd-fsu.edu-oai-fsu.digital.flvc.org-fsu_4056142020-06-24T03:07:46Z Compatibility of Graphite Materials with Block Copolymer Electrolyte for Lithium Batteries Zhou, Sifei (authoraut) Hallinan, Daniel T. (professor directing thesis) Guan, Jingjiao, 1973- (committee member) Chella, Ravindran (committee member) Zheng, Jianping P. (committee member) Florida State University (degree granting institution) College of Engineering (degree granting college) Department of Chemical and Biomedical Engineering (degree granting departmentdgg) Text text Florida State University Florida State University English eng 1 online resource (62 pages) computer application/pdf Graphite has good lifetime and rate capability in liquid electrolyte-based batteries and supercapacitors. Meanwhile, the polymer electrolyte have been considered as a promising technology for battery applications for its safety and flexible cell configuration design which satisfy the requirements of stand-by power and electric vehicles(EV). It is commonly recognized that graphite and PEO-based polymer electrolyte have poor compatibility due to high interfacial resistance and co-intercalation phenomenon. However, it was reported recently that high molecular weight PEO electrolyte along with material processing approaches to graphite materials result in improved compatibility. Motivated by this finding, it is reasonable to expect that further improvements in battery performance can be gained with block compolymer that has mechanical properties sufficient to maintain electrode structure. Therefore, a high molecular weight block copolymer (polystyrene-b-PEO) was used to replace PEO as polymer electrolyte in this study. In addition, the block copolymer has better mechanical properties that improve both thermal and mechanical stability of the cell or might even partially reduce the complicated engineering techniques apply to the graphite material. In this study, the compatibility of two different graphite materials with block copolymer were investigated by using detailed analysis of electrochemical methods that include galvanostatic cycling (GCPL) and electrochemical impedance spectroscopy (EIS). In particular, EIS was used to examine the formation of the solid electrolyte interphase (SEI) on the graphite surface which has significant impact on the cycling performance of the cell. It is concluded that SEI formation in the first few cycles on flake graphite appears to be much more stable than on MCMB leading to better capacity retention. Flake graphite materials have a better compatibility with block copolymer (SEO) comparing to MCMB graphite supported by better cycling performance and electrode-electrolyte interphase property. A Thesis submitted to the Department of Chemical and Biomedical Engineering in partial fulfillment of the requirements for the degree of Master of Science. Fall Semester 2016. November 8, 2016. block copolymer, Lithium battery, SEI Includes bibliographical references. Daniel Hallinan, Professor Directing Thesis; Jingjiao Guan, Committee Member; Ravindran Chella, Committee Member; Jianping Zheng, Committee Member. Chemical engineering FSU_FA2016_Zhou_fsu_0071N_13603 http://purl.flvc.org/fsu/fd/FSU_FA2016_Zhou_fsu_0071N_13603 This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). The copyright in theses and dissertations completed at Florida State University is held by the students who author them. http://diginole.lib.fsu.edu/islandora/object/fsu%3A405614/datastream/TN/view/Compatibility%20of%20Graphite%20Materials%20with%20Block%20Copolymer%20Electrolyte%20for%20Lithium%20Batteries.jpg
collection NDLTD
language English
English
format Others
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topic Chemical engineering
spellingShingle Chemical engineering
Compatibility of Graphite Materials with Block Copolymer Electrolyte for Lithium Batteries
description Graphite has good lifetime and rate capability in liquid electrolyte-based batteries and supercapacitors. Meanwhile, the polymer electrolyte have been considered as a promising technology for battery applications for its safety and flexible cell configuration design which satisfy the requirements of stand-by power and electric vehicles(EV). It is commonly recognized that graphite and PEO-based polymer electrolyte have poor compatibility due to high interfacial resistance and co-intercalation phenomenon. However, it was reported recently that high molecular weight PEO electrolyte along with material processing approaches to graphite materials result in improved compatibility. Motivated by this finding, it is reasonable to expect that further improvements in battery performance can be gained with block compolymer that has mechanical properties sufficient to maintain electrode structure. Therefore, a high molecular weight block copolymer (polystyrene-b-PEO) was used to replace PEO as polymer electrolyte in this study. In addition, the block copolymer has better mechanical properties that improve both thermal and mechanical stability of the cell or might even partially reduce the complicated engineering techniques apply to the graphite material. In this study, the compatibility of two different graphite materials with block copolymer were investigated by using detailed analysis of electrochemical methods that include galvanostatic cycling (GCPL) and electrochemical impedance spectroscopy (EIS). In particular, EIS was used to examine the formation of the solid electrolyte interphase (SEI) on the graphite surface which has significant impact on the cycling performance of the cell. It is concluded that SEI formation in the first few cycles on flake graphite appears to be much more stable than on MCMB leading to better capacity retention. Flake graphite materials have a better compatibility with block copolymer (SEO) comparing to MCMB graphite supported by better cycling performance and electrode-electrolyte interphase property. === A Thesis submitted to the Department of Chemical and Biomedical Engineering in partial fulfillment of the requirements for the degree of Master of Science. === Fall Semester 2016. === November 8, 2016. === block copolymer, Lithium battery, SEI === Includes bibliographical references. === Daniel Hallinan, Professor Directing Thesis; Jingjiao Guan, Committee Member; Ravindran Chella, Committee Member; Jianping Zheng, Committee Member.
author2 Zhou, Sifei (authoraut)
author_facet Zhou, Sifei (authoraut)
title Compatibility of Graphite Materials with Block Copolymer Electrolyte for Lithium Batteries
title_short Compatibility of Graphite Materials with Block Copolymer Electrolyte for Lithium Batteries
title_full Compatibility of Graphite Materials with Block Copolymer Electrolyte for Lithium Batteries
title_fullStr Compatibility of Graphite Materials with Block Copolymer Electrolyte for Lithium Batteries
title_full_unstemmed Compatibility of Graphite Materials with Block Copolymer Electrolyte for Lithium Batteries
title_sort compatibility of graphite materials with block copolymer electrolyte for lithium batteries
publisher Florida State University
url http://purl.flvc.org/fsu/fd/FSU_FA2016_Zhou_fsu_0071N_13603
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