Biomass derived activated carbons for supercapacitors
슈퍼커패시터용 바이오매스 기반 활성탄
- 주제(키워드) Biomass , Activated carbon , Supercapacitor
- 발행기관 고려대학교 대학원
- 지도교수 김웅
- 지도교수 노광철
- 발행년도 2018
- 학위수여년월 2018. 8
- 유형 Text
- 학위구분 박사
- 학과 대학원 신소재공학과
- 원문페이지 132 p
- 실제URI http://www.dcollection.net/handler/korea/000000081377
- UCI I804:11009-000000081377
- DOI 10.23186/korea.000000081377.11009.0000860
- 본문언어 영어
- 제출원본 000045953588
초록/요약
Biomass derived activated carbons for supercapacitors Name: Joah Han Department: Materials Science and Engineering Thesis tutor professor: Woong Kim, Kwang Chul Roh Lignocellulosic and algal biomass (including woody, herbaceous and algal biomass) derived activated carbons with effective properties were prepared for organic electrolyte based supercapacitors. The biomass derived activated carbons indicated all samples showed higher specific surface area than that of commercial activated carbon because of their predominant micropores formed by metallic K gas during alkali activation process unlike physical activation used for preparation of commercial activated carbons. And they also had higher specific capacitance, rate capability and cycle stability than those of commercial activated carbons because of their partially graphitic structure or hierarchical pore structure after alkali activation. It means not only that some composition that lignocellulosic or algal biomass comprise such as cellulose, hemicellulose and lignin or protein and lipid could contribute to make different pore structure including micropores and mesopores (i. e. hierarchical pore structure) but also that their composition’s structure such as carbohydrates and aromatic structure could contribute to be transformed amorphous or partially graphitic structure during alkali activation. These hierarchical pore structure or partially graphitic structure could facilitate ions and electron transfer, respectively, during charging. Eventually, this study provides not only a method for obtaining advanced activated carbons with simultaneously high specific surface area and partially graphitic structure but also the reason why a component obtained in woody biomass after chemical treatment could contribute to be converted to graphitic structure and why algal biomass could make hierarchical pore structure with the highest specific surface area. Further, studies on utilization of waste biomass for supercpacitor’s electrode materials were conducted. Thus, effective utilization of abandoned biomass is beneficial in terms of economic, environmental, and energy saving concerns as carbon disposal of waste products are key concerns in the present climate. Further, we believe that this study will be of interest because it is of wide importance to a number of fields, and represents an advance in the use of sustainable products through the development of an environmentally improved method for obtaining important energy storage products.
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Contents
Abstract iv
Contents vi
List of Figures ix
List of Tables xiv
Chapter 1. Introduction 1
Chapter 2. Theoretical Background 5
2.1 Supercapacitors 5
2.1.1 Electric double layer capacitor 9
2.1.2 Pseudocapacitor 14
2.1.3 Hybrid capacitor 17
2.2 Activated carbons 19
2.3 Biomass 26
Chapter 3. Experimental Section 30
3.1 Material Preparation 30
3.1.1 Chemical Treatment of Woody Biomass 30
3.1.2 Different type Biomass derived Activated Carbons 31
3.2 Fabrication 33
3.2.1 Electrodes 33
3.2.2 Supercapacitors 35
3.3 Characterization 37
3.3.1 Surface Analysis 37
3.3.1.1 Field-emission scanning electron microscopy (FE-SEM) 37
3.3.1.2 X-ray photoelectron spectroscopy (XPS) 37
3.3.2 Structural Analysis 38
3.3.2.1 High-resolution transmission electron microscopy (HR-TEM) 38
3.3.2.2 X-ray diffraction (XRD) 38
3.3.2.3 Raman spectrometry 39
3.3.3 Adsorption Analysis 40
3.3.3.1 Nitrogen adsorption analysis 40
3.3.3.2 Carbon dioxide adsorption analysis 41
3.3.4 Electrochemical Analysis 41
3.3.4.1 Cyclic voltammetry (CV) 41
3.3.4.2 Electrochemical impedance spectroscopy (EIS) 42
3.3.4.3 Galvanostatic charge–discharge (GCD) 42
3.3.4.4 Electrical conductivity 43
Chapter 4. Results and Discussion 45
4.1 Woody Biomass derived Activated Carbons with Partially Graphitic Structure 45
4.1.1 Objective 45
4.1.2 Physical and Chemical properties 49
4.1.3 Electrochemical properties 66
4.1.4 Conclusion 69
4.2 Herbaceous Biomass derived Activated Carbons 71
4.2.1 Objective 71
4.2.2 Physical and Chemical properties 72
4.2.3 Electrochemical properties 81
4.2.4 Conclusion 84
4.3 Algal Biomass derived Activated Carbons with hierarchical pore structure 85
4.3.1 Objective 85
4.3.2 Physical and chemical properties 89
4.3.3 Electrochemical properties 98
4.3.4 Conclusion 104
Chapter 5. Conclusions 105
References 108
