Title Page
Contents
ABSTRACT 11
Ⅰ. Introduction 12
1.1. The Research Background of Supercapacitors 12
1.2. Engineering Core-Shell Structured Nanocomposites 17
1.3. The Electrochemical Parameters for Evaluating the Performance of Supercapacitors 19
Ⅱ. Experimental Method 20
2.1. Materials and Chemicals 20
2.2. Experiment 21
2.2.1. Preparation of the CC@PANI 21
2.2.2. Preparation of the CC@PANI@Co₃O₄ 21
2.2.3. Preparation of the CC@PANI@Co₃O₄@NCM-P 22
2.2.4. Preparation of CC@AC 22
2.2.5. Fabrication of Hybrid Asymmetric Supercapacitors 23
Ⅲ. Characterization 24
3.1. Material Characterization 24
3.2. Electrochemical Characterization 25
Ⅳ. Results and Discussion 26
4.1. Morphological analysis 30
4.2. Structural and phase analysis 35
4.3. Chemical composition analysis 40
4.4. Electrochemical performance 45
4.5. Hybrid asymmetric supercapacitors 54
4.5.1. Aqueous hybrid symmetric supercapacitor (AHAS) 54
4.5.2. Solid-state hybrid symmetric supercapacitor (SHAS) 55
Ⅴ. Conclusions 62
References 64
Appendix 75
Abstract (in Korean) 76
Table 4-1. Comparison of areal capacitance, specific energy density, specific power density, and stability with recently reported asymmetric devices. 61
Figure 1-1. Ragone plots illustrating the power density vs energy density for various energy storage devices. 13
Figure 1-2. Schematic illustration for comparison of the charge storage mechanism between Battery and Supercapacitor. 14
Figure 1-3. The history and development of supercapacitors based on their electrode material, the charge storage mechanism, and performance characteristics. 16
Figure 4-1. Schematic illustration of the preparation process of CC@PANI@Co₃O₄@NCM-P. 27
Figure 4-2. Photographs of CC@PANI, CC@PANI@ZIF-L, CC@PANI@Co₃O₄, and CC@PANI@Co₃O₄@NCM-P. Flexibility test of CC@PANI@Co₃O₄@NCM-P with... 28
Figure 4-3. FE-SEM images of (a) Bare CC and (b) CC@PANI. (The inset images show the water contact angle of Bare CC and CC@PANI, respectively.) (c) Photographs of... 29
Figure 4-4. FE-SEM images of (a, d) CC@PANI@ZIF-L, (b, e) CC@PANI@Co₃O₄, and (c, f) CC@PANI@Co₃O₄@NCM-P. TEM images of (g) CC@PANI@ZIF-L, (h)... 32
Figure 4-5. FE-SEM images of CC@PANI@Co₃O₄@NCM-P electrodes with different CV deposition cycles. (a) 3 cycles, (b) 6 cycles, and (c) 9 cycles. (Insert scale bar : 5 μm) 33
Figure 4-6. FE-SEM images of (a, d) CC@PANI@Co₃O₄@CM-P, (b, e) CC@PANI@Co₃O₄@NM-P, and (c, f) CC@PANI@Co₃O₄@NC-P. 34
Figure 4-7. HR-TEM images of (a) CC@PANI@Co₃O₄, and (b) CC@PANI@Co₃O₄@NCM-P. (c) XRD patterns of CC@PANI@ZIF-L, CC@PANI@Co₃O₄, and... 37
Figure 4-8. TEM-EDS element mapping images of Ni, Co, Mn, P, and O for CC@PANI@Co₃O₄@NCM-P. (Insert scale bar: 500 nm) 38
Figure 4-9. (a) N₂ isotherm analysis for the surface area of CC@PANI@Co₃O₄, CC@PANI@NCM-P and CC@PANI@Co₃O₄@NCM-P. (b) BJH pore size distribution... 39
Figure 4-10. FT-IR spectra of (a) CC@PANI and Pure PANI, (b) CC@PANI@ZIF-L, CC@PANI@Co₃O₄, and CC@PANI@Co₃O₄@NCM-P. 42
Figure 4-11. XPS spectra of CC@PANI@Co₃O₄; (a) survey, (b) Co 2p, (c) O 1s, and (d) C 1s. 43
Figure 4-12. XPS spectra of CC@PANI@Co₃O₄@NCM-P; (a) survey, (b) Ni 2p, (c) Co 2p, (d) Mn 2p, (e) O 1s, and (f) P 2p. 44
Figure 4-13. (a) CV and (b) GCD curves of CC@PANI@ZIF-L. (c) CV and (d) GCD curves of CC@PANI@Co₃O₄. (e) Comparison of mass loading and specific capacitance... 48
Figure 4-14. Comparison of electrochemical performance according to the existence of Co₃O₄ core. (a) The schematic illustration of the core-shell structure advantage in... 49
Figure 4-15. Electrochemical performance of CC@PANI@Co₃O₄@NCM-P electrodes with different CV deposition cycles for supercapacitor. (a) CV curves at 10 mV s⁻¹, (b)... 50
Figure 4-16. Electrochemical performance of different metal phosphate electrodes for supercapacitor. (a) CV curves at 10 mV s⁻¹, (b) GCD curves at 1 mA cm⁻², (c) rate... 53
Figure 4-17. (a-b) FE-SEM images of CC@AC. (c) CV curves at different scan rates, (d) GCD curves at different current densities of CC@AC for anode. 57
Figure 4-18. Electrochemical performance of aqueous hybrid asymmetric supercapacitor (AHAS). (a) CV curves of CC@AC and CC@PANI@Co₃O₄@NCM-P at 10 mV s⁻¹ in... 58
Figure 4-19. Electrochemical performance of solid-state hybrid asymmetric supercapacitor (SHAS). (a) Schematic illustration, (b) CV curves at different scan rates,... 59
Figure 4-20. Practical application of flexible SHAS device (CC@PANI@Co₃O₄@NCM-P//PVA-KOH//CC@AC). Flexibility test: (a) Photographs of the SHAS device with... 60