BỘ GIÁO DỤC VÀ ĐÀO TẠO TRƯỜNG ĐẠI HỌC BÁCH KHOA HÀ NỘI --------------------------------------- NGO QUANG MINH Ngo Quang Minh ELECTRONIC MATERIALS ENGINEERING OF SCIENCE AND SYNTHESIS AND PROPERTIES OF 2D MATERIALS MOS2/GRAPHENE APPLIED FOR ELECTRODES IN SUPERCAPACITOR MASTER THESIS OF SCIENCE MATERIALS SCIENCE 2016-2018 Ha Noi – 2018 17057205064001000000 MINISTRY OF EDUCATION AND TRAINING HANOI UNIVERSITY OF SCIENCE AND TECHNOLOGY --------------------------------------- Ngo Quang Minh SYNTHESIS AND PROPERTIES OF 2D MATERIALS MOS2/GRAPHENE APPLIED FOR ELECTRODES IN SUPERCAPACITOR Major: Science and Engineering of Electronic Materials MASTER THESIS OF SCIENCE MATERIALS SCIENCE SUPERVISOR: Assoc Prof Dr Nguyen Duc Hoa Ha Noi – 2018 CỘNG HÒA XÃ HỘI CHỦ NGHĨA VIỆT NAM Độc lập – Tự do – Hạnh phúc BẢN XÁC NHẬN CHỈNH SỬA LUẬN VĂN THẠC SĨ Họ và tên tác giả luận văn: Ngô Quang Minh Đề tài luận văn: Nghiên cứu tổng hợp và khảo sát tính chất của vật liệu 2 chiều MoS 2/graphen ứng dụng làm điện cực trong siêu tụ điện Chuyên ngành: Khoa học và kỹ thuật vật liệu điện tử Mã số HV: CB160069 Tác giả, Người hướng dẫn khoa học và Hội đồng chấm luận văn xác nhận tác giả đã sửa chữa, bổ sung luận văn theo biên bản họp Hội đồng ngày 30/10/2018 với các nội dung sau: Tiêu đề chương để chữ in hoa, giữa dòng. Sắp xếp lại phần chữ và hình để thu hẹp các khoảng giấy trống nhiều, dẫn tới số trang luận văn có sự thay đổi. Tăng độ phân giải các hình ảnh bị mờ, 3. Đã chỉnh sửa lỗi về mô tả tiêu đề hình 3.
Ngày 5 tháng 11 năm 2018 Giáo viên hướng dẫn Tác giả luận văn CHỦ TỊCH HỘI ĐỒNG STATEMENT OF ORIGINAL AUTHORSHIP I hereby declare that the results presented in the thesis are performed by the author. The research contained in this thesis has not been previously submitted to meet requirements for an award at this or any higher education institutions. Hanoi, 30/9/2018 Signature LIST OF PUBLICATIONS Ngo Quang Minh, Chu Manh Hung, Dang Thi Thanh Le, Nguyen Duc Hoa* and Nguyen Van Hieu (2018), “Synthesis and characterization of MoS2/rGO nanocomposite for supercapacitor applications”, The 9th International Workshop on Advanced Materials Science and Nanotechnology (IWAMSN 2018), Ninh Binh, Vietnam.1 LIST OF TABLES .2 LIST OF ABBREVIATIONS .3 MOTIVATION FOR RESEARCHING. DOUBLE LAYERS MODEL.
GOUY-CHAPMAN MODEL. STERN AND GRAHAME MODEL. BACKGROUND OF SUPERCAPACITOR. ENERGY DENSITY AND POWER DENSITY.
CLASSIFICATION OF SUPERCAPACITORS. ELECTRIC DOUBLE LAYER CAPACITOR. PRINCIPLE, CLASSIFICATION AND RECENT DEVELOPMENT. MOS2/RGO-BASED ELECTRODE MATERIALS OF SUPERCAPACITOR.
OBJECTIVE RESEARCH AND OUTLINE OF THESIS. OUTLINE OF THESIS .32 CHAPTER 2: EXPERIMENTAL SECTION. MATERIALS, EQUIPMENT AND STEPS OF PREPARING MATERIALS FOR ELECTRODE FABRICATION. PREPARATION OF MATERIALS POWDER FOR ELECTRODE FABRICATION.
PREPARATION OF ELECTRODE AND ELECTROLYTIC SOLUTIONS. PREPARATION OF ELECTRODE. PREPARATION OF ELECTROLYTIC SOLUTIONS. METHODOLOGY OF STRUCTURAL CHARACTERIZATION AND CHEMICAL PROPERTIES ANALYSIS .36 CHAPTER 3: RESULTS AND DISCUSSION.
COMPOSITE MOS 2/RGO RESULTS. CRYSTAL STRUCTURE, MORPHOLOGICAL PROPERTIES AND CV RESULTS. EIS ANALYSIS OF MOS2/RGO WITH MASS RATIO 1:3 .58 ACKNOWLEDGEMENT First of all, I would like to express my greatest gratitude to my supervisor, Associate professor. Nguyen Duc Hoa for his friendliness, patience, and great support in the whole period of time doing the master thesis at ITIMS (International Training Institute for Materials Science), HUST (Hanoi university of Science and Technology).
Without his dedicated guidance and encouragement, I might not be able to complete all of the work throughout this master thesis. Secondly, I would like to give my gratitude to other members in my group-iSensors, Associate professor. Nguyen Van Duy, PhD. Chu Manh Hung, PhD.
Dang Thanh Le for giving me a lots support and encouragement throughout the period of doing my master thesis. I also want to thank Assoc. Truong Thi Ngoc Lien (at Engineering Physics Department, HUST) for her great support in Electrochemical Imedance Spectroscopy measuring. Moreover, I am also very grateful to my colleagues, PhD students: Nguyen Van Hoang, Nguyen Xuan Thai for supporting me a lot in experimental work.
I especially would like to show my gratitude to my colleagues, my classmates such as Miss Hong, Miss Phuoc, Mr. Vuong and Mr. Son, who are always by my side for giving me a plenty of supports and advice in two years doing my master thesis at ITIMS. Last but not least, it is my family: my parents, my sibling elder sister, my grandparents, my uncles, my aunts, my cousins and my lover.
Thank you all a lot. Without all of you, I could not go on such an easy way to complete another part of my life. This research was partially funded by the Vietnam National Foundation for Science and Technology Development (Code: 103. 1 LIST OF TABLES Table 1.1 Carbon-based the electrode materials for supercapacitors 25 Table 1.2 Metal oxide-based the electrode materials for supercapacitors 25 Table1.3 Conductive polymers-based the electrode materials for supercapacitors 25 2 LIST OF ABBREVIATIONS IHP Inner Helmholtz Plane 11 OPH Outer Helmholtz Plane 11 BDM Bockris-Devanathan-Muller 11 EDL Electric Double Layer 11 EDLC Electric Double Layer Capacitor 13 Cn Capacitance of negative electrode 17 Cp Capacitance of positive electrode 17 Cdiff Capacitance of diffusive layer 17 CT Total capacitance of a supercapacitor 17 EC Electrochemical Capacitor 18 ERS Equivalent Resistance Solution 18 rGO Reduced Graphite Oxide 26 GO Graphite Oxide 26 BET Brunauer – Emmett – Teller 26 EIS Electrochemical Impedance Spectroscopy 26 MWCNT Multi-Wall Carbon NanoTube 28 PEG Polyethylene glycol 30 DI De-ionized 33 PTFE Polytetrafluoroethylene 36 XRD X-ray Diffraction 36 SEM Scanning Electrons Microscopy 36 CV Cyclic Voltammetry 37 3 wt weight 46 Cm Specific capacitance 51 RS Solution Resistance 55 Cdl Double Layer Capacity 55 Rct Charge transfer resistance 56 4 LIST OF FIGURES Figure 1.
Models of the electrical double-layer at a positively charged surface: (a) the Helmholtz model, (b) the Gouy–Chapman model, and (c) the Stern model showing the inner Helmholtz plane (IHP) and outer Helmholtz plane (OHP). ψ0 and ψ are the potentials at the electrode surface and the electrode/electrolyte interface, respectively [13]. A double layer model including layers of solvent [15]. (a) Principal setup of an EDLC with porous carbon electrodes on current collectors separated by an ion conducting electrolyte.
Classification of electrolytes [30]. Diagram of effects of range of working temperature on electrolyte in some ways [12]. Ragone plot shows a comparison of some main types of energy storage devices in term of power density and energy density [19, 37]. Classification of supercapacitor based on electrode materials [39].
A schematic diagram of EDLCs and description of potential change through interface of electrode/electrolytic solutions when applied an external voltage [41]. Different types of pseudocapacitive behavior from B. An illustrative example of hybrid supercapacitor [30]. The synthetic procedure of the MoS 2/rGO composite 35 5 Figure 2.
X-ray diffraction diagram of MoS 2 synthesized by hydrothermal method at different temperature 160, 180 and 200oC 38 Figure 3. Specific capacitance value of MoS 2 prepared by hydrothermal processes in 24h depends on temperature treatments. Raman shift spectrum of MoS 2 synthesized by hydrothermal method at different reaction-time 24h, 36h and 48h. Reaction time (24h, 36h and 48h) dependence of specific capacitance (C m) of MoS 2-based electrodes prepared by hydrothermal method at 200oC.
Raman spectra of: a) Graphite; b) Graphite oxide (GO). a) X-ray diagram of rGO; b) SEM image of rGO; c) CV curve of rGO- based electrode. a) X-ray diagram of the nanocomposites MoS2/rGO 1:3; b) SEM image of the nanocomposites MoS2/rGO 1:3; c) CV curve of the nanocomposites MoS2/rGO 1:3 -based electrode. a) Raman spectrum of the nanocomposites MoS2/rGO 1:1, b) SEM image of the nanocomposites MoS2/rGO 1:1, c) CV curve of the nanocomposites MoS2/rGO 1:1 -based electrode.
a) Raman spectrum of the MoS2/rGO 3:1 composite , b) SEM image of the MoS2/rGO 3:1 composite c) CV curve of the MoS2/rGO 3:1 composite - based electrode. a) Raman spectrum of MoS2 , b) SEM image of MoS2, c) CV curves of MoS2-based electrode. CV curves comparison of the composites MoS2/rGO with different contents of MoS2. Specific capacitance values of the composites MoS2/rGO-based electrodes with different contents of MoS 2.
CV curves of the composites MoS2/rGO 1:3 at different scan rates. Scan rates dependence of specific capacitance values of MoS 2/rGO- based electrode with mass ratio MoS2 on rGO 1:3. Concentration of Na 2SO4 dependence of specific capacitance of MoS2/rGO (1:3) based the electrode. A comparison of CV curves of MoS2/rGO with mass ratio 1:3 between Na 2SO4 1M and 1M KCl solutions.
A comparison of CV curves of MoS2/rGO with mass ratio 1:3 between the 1st cycle and the 200th cycle. EIS results of the composites MoS 2/rGO with mass ratio 1:3 in 1M Na 2SO4 solution.55 7 MOTIVATION FOR RESEARCHING In the development of human civilization, energy is always one of the most burning topics because of its profound and comprehensive impacts on almost every aspects of life such as science, medical, education and a lot of others. It is completely true that energy crisis is a real big challenge in this century because human is facing the limitation of non-renewable fossil fuels as coal, gas, oil [1, 2]. Besides, emissions from those sources are attributed to causing many negative problems to the environment, especially climate change, an urgently global issue, and greenhouse gas [41].
That urges researchers and scientists attempt to develop renewable and clean energy sources for purpose of sustainable development parallel to friendliness with the environment. Transportation is one of the pioneer sectors to apply the advances of renewable energy with hybrid vehicles manufactured [4–6]. Solar energy [31] is more and more popular as a source of generating electricity. In addition, enhancing storage and conversion energy capacity of materials and devices is also attracted huge research from many researchers.
Nevertheless, wind and solar energy is not kind of consistent sources creating energy in all cases. Hybrid or electric vehicles would not be popular with all people without enhancing energy storage capacity systems, reducing the time of charging/discharging compared to batteries performance. Fortunately, there is a very suitable solution namely “supercapacitor” [17], which is considered as the key factor to address issues mentioned in energy systems for spreading applications in real life. Nowadays, many 2D composite materials are strongly attracted to research for the electrode materials of the supercapacitors because of their very unique structures, high electric conductivity, high surface area, high stability and friendly with the environment [80].
The MoS2 /rGO composite is one of the typical representatives of 2D family, which have been focused on developing for the electrode materials in the supercapacitors. However, electrochemical performance of MoS 2/rGO composites is strongly dependent on their composition, geometry, surface area, and etc. Herein, we dedicate on the utilizing this material for supercapacitor. Double layers model 1.
Helmholtz model In 1853, Helmholtz was the first scientist setting up the idea of an electric double layer. There is an electrostatic charge separation at the interface between the solid electrode and electrolyte solutions when applying a voltage, figure 1. This model is similar to a conventional capacitor and therefore, Helmholtz capacitance of the double layer can be calculated through the followed equation. (1) d It is true that the Helmholtz model obtains better results when applied for a high concentration of electrolyte solutions.
In practical, most supercapacitor is utilized with concentrated ion solutions. That is the reason why this model is still being used in some simple calculation. However, it is also true that the Helmholtz model about electric double layer does not consider to an effect of diffusion of other ions in the electrolyte solution to the first layer absorbed before. Therefore, the obtained results in capacitance followed the model is not completely matched with the practical phenomenon.