표제지
목차
ABSTRACT 12
제1장 서론 15
제2장 이론적 배경 19
제1절 고온형 Na/NiCl₂ 이차전지 19
제2절 Na⁺-β/β"-Al₂O₃ 고체전해질 21
제3절 기상전환법 (Vapor Phase Conversion) 24
제4절 분위기 분말 (Na Source) 27
제3장 실험 31
제1절 α -alumina/YSZ Composite 제조 31
1. 원료 및 조성 31
2. ZTA 제조 32
제2절 분위기분말 (Na source) 제조 35
1. 원료 및 조성 35
2. 혼합 및 분쇄, 합성 36
제3절 기상전환공정 (Vapor Phase Conversion) 38
1. 분위기분말 성형체 제조 38
2. 분위기 분말, 분위기 팩을 사용한 기상전환공정 38
제4절 Multilayer stacking 방법을 통한 기상전환공정 42
제4장 분석 44
제1절 상 관계 분석 44
제2절 상대 밀도 분석 46
제3절 미세구조 분석 48
제4절 EDX 분석 48
제5절 XRF 분석 48
제6절 이온 전도도 분석 49
제5장 결과 및 고찰 51
제1절 분위기분말 내 상 안정화제 종류에 따른 기상전환공정 후 Na⁺-β/β"-Al₂O₃ 고체전해질 분석 51
1. 상 관계 및 밀도 분석 51
2. 미세구조 분석 53
3. 이온전도도 분석 55
제2절 분위기분말 하소공정 여부 및 분말 형태에 따른 기상전환 공정 후 Na⁺-β/β"-Al₂O₃ 고체전해질 분석 57
1. 상 관계 및 밀도분석 57
2. 미세구조 분석 60
3. EDX 분석 63
4. 이온전도도 분석 65
제3절 분위기팩 재사용 횟수에 따른 기상전환 공정 후 Na⁺-β/β"-Al₂O₃ 고체전해질 및 분위기분말 분석 67
1. 상 관계 분석 67
2. 이온전도도 분석 69
3. 분위기분말 내 Na₂O 분석 72
제4절 Multilayer stacking 방법을 통해 기상전환 공정 후 Na⁺-β/β"-Al₂O₃ 고체전해질 분석 73
1. 상 관계 분석 73
2. 이온전도도 분석 75
제6장 결론 78
참고문헌 80
국문초록 85
Table 1. Current status of domestic ESS fire 18
Table 2. Comparison of Na-based batteries and Lithium ion battery 20
Table 3. Structural properties of Na⁺-β-Al₂O₃ and Na⁺-β"-Al₂O₃ 23
Table 4. Process time and power consumption according to include calcination process and without calcination process when manufacturing Na source 30
Table 5. Specification of raw materials 31
Table 6. Specification of raw materials 35
Table 7. Relative density of BASE according to type of stabilizer in Na source 52
Table 8. Phase fraction and Relative density of BASE after VPC according to type of Na source 59
Table 9. Phase fraction and Ionic conductivity of BASE at 200 ℃ according to reusing of green compaction 71
Table 10. Analysis of content changes of Na source after VPC according to reusing of green compaction 72
Table 11. Phase fraction and Ionic conductivity of BASE at 200 ℃ after multilayer stacking VPC 77
Figure 1. Configuration of ESS 17
Figure 2. Worldwide ESS scale and LIB, ESS installation costs 17
Figure 3. Pictures of ESS fire 18
Figure 4. A novel Na/NiCl₂ cell design Left : Tublar cell, Right : planar cell 20
Figure 5. Crystal structure of Na⁺-β/β"-Al₂O₃ ; (a) Na⁺-β-Al₂O₃, (b) Na⁺-β" -Al₂O₃ 22
Figure 6. Vapor Phase Conversion mechanism for Na⁺-β/β"-Al₂O₃ 26
Figure 7. SEM image of specimen in conversion process 26
Figure 8. Schematic diagram of VPC using Na Source powder type 28
Figure 9. Powders stick to BASE after VPC process 29
Figure 10. Schematic diagram of VPC after modifying the shape of Na source powder 29
Figure 11. Na source state change (Raw material → Na⁺-β/β" -Al₂O₃) 30
Figure 12. Picture of uni-axial press mold 33
Figure 13. Sintering schedule for ZTA by a solid state reaction 34
Figure 14. Schematic diagram for manufacturing of Na source (a) included calcination (b) without calcination 37
Figure 15. Schematic diagram for manufacturing of BASE by Vapor phase conversion 40
Figure 16. Vapor Phase Conversion (VPC) schedule for manufacturing of BASE 40
Figure 17. Apparatus for α -alumina crucible 41
Figure 18. Schematic diagram of VPC by Mutilayer stacking 43
Figure 19. Schematic diagram of the Archimedes method 47
Figure 20. Ionic conductivity measurement method of BASE 50
Figure 21. Nyquist plot of BASE 50
Figure 22. XRD patterns of BASE after VPC according to type of stabilizer in Na source 52
Figure 23. SEM image of BASE according to type of stabilizer in Na source (a) MgO (b) Li₂O 54
Figure 24. Resistance of BASE according to type of stabilizer in Na source at 200 ℃ 56
Figure 25. XRD patterns of BASE after VPC according to type of Na source 58
Figure 26. SEM images of BASE after VPC according to type of Na source (a) Na⁺-β"-Al₂O₃ powder (b) Green powder (c) Green compaction 62
Figure 27. EDX analysis of BASE after VPC using Green compaction as a Na source 64
Figure 28. Ionic conductivity of BASE after VPC according to type of Na source with rising temperature at 150 ~ 350 ℃ 66
Figure 29. XRD patterns of BASE after VPC according to reusing of green compaction 68
Figure 30. Resistance of BASE at 200 ℃ after VPC according to reusing of green compaction 70
Figure 31. XRD patterns of BASEs after multilayer stacking VPC 74
Figure 32. Ionic conductivity of BASE with rising temperature at 150 ~ 350 ℃ after multilayer stacking VPC 76