Development and Characterization of Advanced Polymer Electrolyte for Energy Storage and Conversion Devices

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dc.contributor.authorWang, Yingen
dc.contributor.committeechairMadsen, Louis A.en
dc.contributor.committeememberMoore, Robert Bowenen
dc.contributor.committeememberLong, Timothy E.en
dc.contributor.committeememberDucker, William A.en
dc.contributor.committeememberFrazier, Charles E.en
dc.contributor.departmentLearning Sciences and Technologiesen
dc.date.accessioned2018-07-04T06:00:26Zen
dc.date.available2018-07-04T06:00:26Zen
dc.date.issued2017-01-09en
dc.description.abstractAmong the myraid energy storage technologies, polymer electrolytes have been widely employed in diverse applications such as fuel cell membranes, battery separators, mechanical actuators, reverse-osmosis membranes and solar cells. The polymer electrolytes used for these applications usually require a combination of properties, including anisotropic orientation, tunable modulus, high ionic conductivity, light weight, high thermal stability and low cost. These critical properties have motivated researchers to find next-generation polymer electrolytes, for example ion gels. This dissertation aims to develop and characterize a new class of ion gel electrolytes based on ionic liquids and a rigid-rod polyelectrolyte. The rigid-rod polyelectrolyte poly (2,2'-disulfonyl-4,4'-benzidine terephthalamide) (PBDT) is a water-miscible system and forms a liquid crystal phase above a critical concentration. The diverse properties and broad applications of this rigid-rod polyelectrolyte may originate from the double helical conformation of PBDT molecular chains. We primarily develop an ionic liquid-based polymer gel electrolyte that possesses the following exceptional combination of properties: transport anisotropy up to 3.5×, high ionic conductivity (up to 8 mS cm⁻¹), widely tunable modulus (0.03 – 3 GPa) and high thermal stability (up to 300°C). This unique platform that combines ionic liquid and polyelectrolyte is essential to develop more advanced materials for broader applications. After we obtain the ion gels, we then mainly focus on modifying and then applying them in Li-metal batteries. As a next generation of Li batteries, the Li-metal battery offers higher energy capacity compared to the current Li-ion battery, thus satisfying our requirements in developing longer-lasting batteries for portable devices and even electric vehicles. However, Li dendrite growth on the Li metal anode has limited the pratical application of Li-metal batteries. This unexpected Li dendrite growth can be suppressed by developing polymer separators with high modulus (~ Gpa), while maintaining enough ionic conductivity (~ 1 mS/cm). Here, we describe an advanced solid-state electrolyte based on a sulfonated aramid rigid-rod polymer, an ionic liquid (IL), and a lithium salt, showing promise to make a breakthrough. This unique fabrication platform can be a milestone in discovering next-generation electrolyte materials.en
dc.description.degreePh. D.en
dc.format.mediumETDen
dc.identifier.othervt_gsexam:9276en
dc.identifier.urihttp://hdl.handle.net/10919/83859en
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectPolymer Electrolytesen
dc.subjectIon Gelsen
dc.subjectLiquid Crystalline Polymeren
dc.subjectRigid-rod Polyelectrolytesen
dc.subjectMolecular Alignmenten
dc.subjectIon Transporten
dc.subjectPolymer Characterizationen
dc.subjectLi-metal Batteryen
dc.titleDevelopment and Characterization of Advanced Polymer Electrolyte for Energy Storage and Conversion Devicesen
dc.typeDissertationen
thesis.degree.disciplineMacromolecular Science and Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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