Title Page

Contents

Abstract 19

Chapter 1. General Introduction 21

Chapter 2. Background and Literature Review: Aluminum-air Batteries 25

2.1. Advantages of aluminum-air batteries 25

2.2. Working principles of aluminum-air batteries 29

2.3. Alkaline alumilum-air batteries 31

2.4. Corrosion and corrosion inhibition for Al anodes 33

Chapter 3. Chrysanthemum coronarium leaves extract as an interface chemistry additive for aluminum anode in aluminum-air batteries 36

Abstract 36

3.1. Introduction 37

3.2. Materials and methods 39

3.2.1. Specimens and test solutions preparation 39

3.2.2. Hydrogen gas evolution tests 40

3.2.3. Electrochemical measurements 42

3.2.4. Surface investigations 43

3.2.5. Quantum chemical calculations 43

3.2.6. Battery performance tests 44

3.3. Results and discussion 46

3.3.1. H₂ evolution tests 46

3.3.2. Electrochemical measurements 47

3.3.3. Adsorption behavior 57

3.3.4. Surface investigation 60

3.3.5. Inhibition mechanism - Quantum chemical calculations 68

3.3.6. Battery performance 72

3.4. Conclusions 76

Chapter 4. Improving the performance of primary Al-air batteries using a hydrogen bond-rich glycerol solvent additive related to water electrochemical environment 79

Abstract 79

4.1. Introduction 80

4.2. Experimental 83

4.2.1. Materials and chemicals 83

4.2.2. Characterizations 83

4.2.3. Computational methods 84

4.2.4. Electrochemical measurements 85

4.2.5. H₂ evolution tests 87

4.2.6. Battery performance tests 88

4.3. Resutls and discussions 91

4.3.1. Electrolyte characterizations 91

4.3.2. Electrochemical and H₂ evolution tests 100

4.3.3. Battery performance 105

4.3.4. Comparison with other methods 111

4.4. Conclusions 112

Chapter 5. Background and Literature Review: Lithium metal batteries 114

5.1. Advantages of Li-metal batteries 114

5.2. Categories of lithium-metal batteries 117

5.3. Liquid lithium metal batteries with intercalation cathodes 118

5.3.1. Lithium metal anodes 118

5.3.2. Conventional intercalation cathodes 118

5.3.3. Liquid electrolytes 120

5.4. Solid electrolyte interphase (SEI) and main challenges of lithium metal batteries 122

5.5. Strategies to protect Li anodes in Li metal batteries 125

5.6. Characterizations of ideal solid electrolyte interface (SEI) layers 126

Chapter 6. N,N-Diallyl-2,2,2-Trifluoroacetamide as an electrolyte additive for high electrochemical stability of ultrathin lithium metal anodes 129

Abstract 129

6.1. Introduction 130

6.2. Experimental section 131

6.2.1. Materials 131

6.2.2. Battery preparation 132

6.2.3. Electrochemical measurements 132

6.2.4. Characteristics of electrodes and electrolytes 134

6.2.5. Calculation methods 136

6.3. Results and discussions 137

6.3.1. Theoretical calculations 137

6.3.2. Symmetric cells 143

6.3.3. Characterizations of electrolytes 156

6.3.4. Full cells 160

6.4. Conclusions 162

Chapter 7. Summary and Future works 164

7.1. Summary of results 164

7.2. Future works 166

References 167

Appendices 189

〈Appendix 1〉 189

〈Appendix 2〉 193

〈Appendix 3〉 Research Achievements 200

논문요약 202

Table 3.1. Potentiodynamic polarization parameters for 4N Al in 4 M NaOH containing different CCLE concentrations. 51

Table 3.2. Nyquist plots parameters of 4N Al electrode in 4 M NaOH solution in the introduction of different CCLE quantities. 56

Table 3.3. Parameters derived and calculated based on Freundlich adsorption isotherm. 58

Table 3.4. The atomic composition of 4N Al in 4 M NaOH and 4 M NaOH in the introduction of 4.5 g/L of CCLE. 65

Table 3.5. Adsorption energy of the main compounds in CCLE on the Al surface. 69

Table 3.6. Performance parameters of Al-air battery in 4 M NaOH solution with different CCLE concentrations. 74

Table 4.1. The system parameters of different electrolytes. 85

Table 5.1. Commonly employed electrolytes and their physical properties for Li metal batteries. 121

Table 5.2. Ionic conductivity of different components in SEI layer. 128

Figure 2.1. The comparison between batteries for gravimetric specific energy and volumetric energy density. 26

Figure 2.2. Applications of metal-air batteries. 26

Figure 2.3. The comparison between metals for galvanostatic capacity, volumetric capacity, abundance, cost, standard potential, cation radius, and... 28

Figure 2.4. Schematic of an Al-air battery with a cathode containing 3 layers. 29

Figure 2.5. Schematic illutration of a 3 layers air cathode. 30

Figure 2.6. Pourbaix diagram of the Al-water system. 32

Figure 2.7. The schematic illutrations and reactions within of alkaline Al-air batteries. 35

Figure 2.8. The strategies for suppressing of aluminum corrosion. 35

Figure 3.1. The preparation of CCLE electrolyte additive. 40

Figure 3.2. Schematic diagram of the water substitution method for measuring H₂ evolution. 41

Figure 3.3. Photographs of an actual Al-air full cell for experiments on the gas diffusion electrode (GDE) side (a-1) and on the aluminum sheet anode side (a-... 45

Figure 3.4. The H₂ evolution rate of 4N Al in 4 M NaOH with varying CCLE additive concentrations. 47

Figure 3.5. Polarization curves of 4 N Al in 4 M NaOH with different CCLE concentrations. 50

Figure 3.6. Nyquist plots and equivalent circuit for 4N Al in 4 M NaOH in the presence of various CCLE concentrations. 55

Figure 3.7. An equivalent circuit employed for analyzing of Nyquist curves. 55

Figure 3.8. Freundlich isotherm plots for the adsorption of CCLE on 4N Al in 4 M NaOH solution containing various CCLE quantities. 59

Figure 3.9. SEM micrographs of the samples: (a) un-treated 4N Al, (b) 4N Al after dipping in 4 M NaOH solution, and (c) 4N Al after dipping in 4 M NaOH... 60

Figure 3.10. The 2D and 3D AFM images of 4N Al samples: (a) un-treated in 4 M NaOH, (b) dipping in 4 M NaOH, (c) dipping in 4 M NaOH with 4.5 g/L of... 63

Figure 3.11. FT-IR spectra of CCL powder, 4N Al after corrosion in 4 M NaOH, and 4N Al after immersion in 4 M NaOH containing 4.5 g/L of CCLE. 64

Figure 3.12. High-resolution spectra of Al 2p, O 1s, and C 1s corresponded to the 4N Al sample in 4 M NaOH (a, b, c), and 4N Al sample in 4 M NaOH... 66

Figure 3.13. Mulliken charge populations analysis of the main compounds in CCLE: (a) (Z)-Chrysanthenyl acetate, (b) Bonyl acetate, (c) E,E-α-... 70

Figure 3.14. Adsorption state of the main compounds in CCLE on the (1 1 1) Al surface: (a) (Z)-Chrysanthenyl acetate, (b) Bonyl acetate, (c) E,E-α-... 71

Figure 3.15. Discharge curves of Al-air battery in 4 M NaOH containing different CCLE concentrations. 73

Figure 3.16. Cycle performance of Al-air battery in 4 M NaOH and 4 M NaOH containing CCLE 4.5 g/L(consisting of a 60 minutes rest period at OCP and 120... 76

Figure 4.1. Schematic diagram of the water substitution method for measuring H₂ evolution. 88

Figure 4.2. Photographs of an actual Al-air full cell for experiments on the gas diffusion electrode (GDE) side (a-1) and on the aluminum sheet anode side (a-... 90

Figure 4.3. (a) DSC curves, (b) local FT-IR of HOH bending, (c) Local Raman spectra of OH modes of different electrolytes. 94

Figure 4.4. (a) The binding energies of various H-bond cases formed in electrolytes, (b) HER mechanism in different electrolytes, Snapshot and... 99

Figure 4.5. LSV curves of different electrolytes. 100

Figure 4.6. Tafel curves of Al anodes in different electrolytes. 101

Figure 4.7. Released H₂ evolution of Al anodes in different electrolytes. 101

Figure 4.8. H₂ evolution rate of Al anodes and corrosion inhibition efficiency of glycerol on Al anodes. 102

Figure 4.9. SEM images with marked maximum corrosion hole of Al anodes in (a) Blank, (b) 1Gly, (c) 2Gly, (d) 3Gly, and (e) 4Gly for 60 minutes of... 105

Figure 4.10. Discharge curves of Al-air batteries in different electrolytes. 106

Figure 4.11. Al consumption quantities and corresponding capacity density of Al-air batteries in different electrolytes. 106

Figure 4.12. On/off cycling plots of Al-air batteries in 4 M NaOH in the absence and presence of 20% glycerol a 10 mAh/cm². 107

Figure 4.13. Comparison of the capacity density of Al-air batteries achieved using different methods. 111

Figure 5.1. History lithium batteries. 114

Figure 5.2. Energy density and specific energy of various batteries. 116

Figure 5.3. Comparison the conventional intercalation cathodes in terms of cost, lifespan, specific energy, safety, specific power, and performance. 119

Figure 5.4. Schematic of LillLFP batteries using LiPF₆ in EC:DMC electrolyte. 122

Figure 5.6. Schematic illustration of dendrite growth on the Li anode surface. 124

Figure 5.7. Schematic of Li metal batteries, and the main challenges associated with the formation of dendrites and low CE of Li metal anodes. 124

Figure 5.8. Various strategies to mitigate the dendrite growth. 125

Figure 5.9. Advantages of using electrolyte additives in comparison with other strategies for improving Li metal anodes. 126

Figure 5.10. Schematic illustration of the dendrite growth process with a SEI layer containing low conductivity species (σ〈10⁻⁶ S/cm) and high conductivity... 127

Figure 6.1. (a) Structure of N-N-diallyl-2,2,2-trifluoroacetamide (NDT),(b) Electrostatic potential (ESP) maps of EC, DMC, NDT molecules. 141

Figure 6.2. (a) Snapshot of 1 M LiPF₆ in EC:DMC, (b) Radical distribution functions (g (r)lines) (solid lines) amd coordination numbers (N (r) lines) (dash... 142

Figure 6.3. (a) Snapshot of 1 M LiPF₆ in EC:DMC containing NDT, (b) Radical distribution functions (g (r)lines) (solid lines) amd coordination numbers (N (r)... 142

Figure 6.4. HOMO and LUMO energy levels of the composition molecules in different electrolytes. 143

Figure 6.5. (a) Voltage profiles of Li plating/stripping processes in the LillLi symmetric cells in different electrolytes at 1 mA/cm², (b) Corresponding cycles... 145

Figure 6.6. The selected voltage-time curves at (a) the initial 5 cycles, (b) from 20th to 25th cycles in different electrolytes.[이미지참조] 146

Figure 6.7. (a, b) Nyquist spectra of the LillLi cells at different cycles in BL and NDT-2 electrolytes, respectively. (c) EIS spectra of the cells before cycling in... 149

Figure 6.8. SEM images of cycled Li electrodes in the LillLi symmetric cells in BL electrolyte (a-c) and NDT-2 electrolyte (e-g) after 1st, 25th, 50th cycles....[이미지참조] 152

Figure 6.9. (a) XPS spectra of the Li electrodes from the LillLi symmetric cells after being cycled the 25 cycles in BL and NDT-2 electrolytes. (b-f) High-... 155

Figure 6.10. (a) Contact angles between the PP separators and different electrolytes. (b) The electrolyte uptake of the PP separators soaked in different... 159

Figure 6.11. (a) Rate performance of the LillLFP cells at 2.5 - 4.0 V. (b) Cycling performance of the LillLFP cells in different electrolytes at 0.3 C. (c, d)... 161

 전지 내에서 발생하는 부수 반응은 실제 특정 용량 및 에너지 밀도 값을 이론적인 값보다 감소시킵니다. 이 문제를 해결하기 위해 전지 전해질에 전해질 첨가제를 첨가하여 이러한 부수 반응을 효과적으로 억제함으로써 전지의 성능을 향상시킵니다.

알루미늄은 금속-공기 전지에서 양극 소재로 강력한 선택지로 나타납니다. 이는 환경 친화성, 저렴한 가격, 높은 재활용 가능성, 그리고 지구의 지각에서 가장 풍부한 금속인 8.3%의 함량 등으로 인한 것입니다. 특히, 알루미늄은 2980 mAh/g 의 높은 특정 용량을 가지고 있어 리튬(3860 mAh/g)에 이어 두 번째로 순위되는 것으로 알려져 있습니다. 그러나 알칼리 전해질에서는 알루미늄 양극이 자체 부식을 경험하게 되며, 이는 전원 에너지를 생성하는 전기화학 반응에 기여하는 대신 부식 반응에서 양극 소재의 소모를 일으켜 알칼리 알루미늄 공기 전지의 성능을 저하시킵니다. 3 장, 4 장에서는 부식 억제제로 작용하는 두 가지 서로 다른 종류의 전해질 첨가제가 알루미늄-공기 전지에서 알루미늄 양극의 자체 부식을 완화시키는 데 사용되었습니다. 국화잎 추출물은 큰 유기 화합물이 포함된 기능성 그룹을 가진 흡착 메커니즘을 통해 알루미늄 부식을 억제합니다. 한편, 유기 용매인 글리세롤은 전해질의 수소 결합 네트워크 재구성을 통해 수용성 전해질에서 수분 활동을 감소시켜 알루미늄 양극 표면에 대한 수분의 공격 및 수분 감소 반응에서의 수소 발생 반응을 줄이게 됩니다.

1 차 알루미늄-공기 전지는 상위형 리튬이온 전지의 2 배에서 10 배에 이르는 매우 높은 이론적 에너지 밀도를 자랑하지만, 주목할 만한 단점은 재충전이 불가능하다는 것입니다. 특히 고방전 장치에서의 빈번한 교체 필요는 불편할 수 있습니다. 그 결과, 재충전이 가능하고 고방전 응용에 적합한 이차 전지가 널리 채택되었습니다. 그러나 이차 리튬 금속 전지는 여전히 실용적인 응용에 앞서 몇 가지 과제에 직면하고 있으며, 특히 리튬 덴드라이트 성장 문제가 있습니다. 이 성장은 낮은 특정 용량, 감소된 수명, 단락 가능성에서 비롯된 안전 문제에 기여합니다. 6 장에서는 N,N-다이알릴-2,2,2-트리플루오로아세트아마이드(NDT)가 전해질 첨가제로 도입되어 리튬 덴드라이트 성장을 억제하고 결과적으로 전지의 성능을 향상시키는 데 사용되었습니다.