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Ion conduction and ionic speciation of Li-ion battery (LIB) electrolytes

Title
Ion conduction and ionic speciation of Li-ion battery (LIB) electrolytes
Translated Title
리튬 이온 배터리 전해액의 용액 구조분석을 통한 이온 전달 기작 분석
Authors
Hyejin Lee
DGIST Authors
Hyejin Lee; Lee, HochunLee, Yong Min
Advisor(s)
이호춘
Co-Advisor(s)
Lee, Yong Min
Issue Date
2021
Available Date
2022-07-07
Degree Date
2021/02
Type
Thesis
Keywords
Li-ion battery, electrolytes, solution structure, Ion speciation, ion conduction, 리튬 이온 배터리 전해액, 전해액 구조, 이온 종 분화, 이온 전달 기작, 리튬 호핑 현상, 이온 전도도
Table Of Contents
I. INTRODUCTION 1 1.1 Carbonate-based electrolytes 1 1.2 DMSO-based electrolytes 2 1.3. Nitrile-based electrolytes 2 1.4. References 4 II. THEORY 5 2.1 Raman spectroscopy 5 2.1.1 Determination of the coordination/solvation numbers 5 2.2 Dielectric relaxation spectroscopy (DRS) 6 2.2.1 Dielectric measurement 6 2.2.2 Spectra analysis 10 2.2.3 Deriving the concentration of ion species 12 2.2.4 Complimentary information to the Raman 14 2.3. Self-diffusivity of the salt 15 2.3.1 Derivation of Dsalt and improved conductivity parameter 15 2.4 Ion conduction mechanism 17 2.4.1 Walden plot 17 2.4.2 Vehicular and hopping conduction 17 2.5 References 19 III. EXPERIMENT 24 3.1 Materials 24 3.2 Ionic conductivity and viscosity 24 3.3 Raman spectroscopy 24 3.4 Dielectric relaxation spectroscopy (DRS) 25 3.5 Pulsed-field Gradient Nuclear magnetic resonance (PFG-NMR) 26 3.6 Density Function Theory (DFT) calculation 27 3.7 References 29 IV. RESULT and DISCUSSION 30 4.1 Single carbonates electrolyte DMC vs. DEC 30 4.1.1 Ionic conductivity, viscosity, and Walden plot 30 4.1.2 Ion speciation by Raman spectroscopy 33 4.1.3 Dielectric properties of solutions 34 4.1.4 Solvent speciation 35 4.1.5 Density functional theory (DFT) calculation 41 4.1.6 Conclusion 46 4.2 Mixed Carbonate electrolytes 47 4.2.1 Ionic conductivity and viscosity 49 4.2.2 A degree of salt dissociation 51 4.2.3 Ion speciation by DRS 55 4.2.4 Solvent speciation 59 4.2.5 Density functional theory (DFT) calculation 62 4.2.6 Conclusion 65 4.3 DMSO-based electrolytes 67 4.3.1 Ionic conductivity, viscosity, and Walden plot 67 4.3.2 Ionic speciation 69 4.3.3 Solvent speciation 75 4.3.4 Ionic conduction 78 4.3.5 Conclusion 82 4.4 Li-ion hopping conduction in Acetonitrile (AN) 83 4.4.1 Ionic conductivity and viscosity 83 4.4.2 Self-diffusion coefficient 84 4.4.3 Solvent and ion speciation 86 4.4.4 Ion conduction mechanism 89 4.4.5 Rate performance in Li-ion batteries 94 4.4.6 Conclusion 97 4.5 References 99
URI
http://dgist.dcollection.net/common/orgView/200000362925
http://hdl.handle.net/20.500.11750/16670
DOI
10.22677/thesis.200000362925
Degree
Doctor
Department
Energy Science & Engineering
University
DGIST
Related Researcher
  • Author Lee, Hochun Electrochemistry Laboratory for Sustainable Energy(ELSE)
  • Research Interests Lithium-ion batteries; Novel Materials for rechargeable batteries; Novel energy conversion;storage systems; Electrochemistry; 리튬이차전지; 이차전지용 신규 전극 및 전해액; 신규 에너지변환 및 저장 시스템; 전기화학
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Department of Energy Science and EngineeringThesesPh.D.


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