고 에너지밀도를 가지는 양극소재 개발

다국어 초록 (Multilingual Abstract)

The Ni-rich layered oxides (Ni ≥0.8) material can significantly reduce the amount of toxic and expensive Co from the structure. Moreover, the reversible capacity could be increased by 15-20% compared to LiCoO2 (LCO) with a voltage as high as ~4.2 V. However, the current battery market requires far higher energy density and stability than existing lithium-ion batteries. NMC materials are reported to suffer mass transfer resistance because of the cation mixing and structural change during the battery cycling, thus the capacity fading phenomenon occurs.
In this study, we investigated the stabilization effect of Ca in the Ni-rich layered compound, Li[Ni0.83Co0.12Mn0.05]O2, and then Ca was added to the modified secondary particles to lower the degree of cationic mixing of the final particles, aiming at improving the stability of the physical and chemical bonding. For the optimization of the final grains added with Ca, the Ca content (x = 0, 2.5, 5.0, 10.0 at.%) versus Li was analyzed.

목차 (Table of Contents)

• 1. 서론 ··············································································· 1
• 2. 이론적 배경 ····································································· 4
• 2.1 리튬이차전지의 작동 원리 ················································· 4
• 2.2 양극소재의 종류 ······························································· 6
• 2.2.1 층상구조계 양극 소재 ······················································· 7
• 2.2.2 스피넬계 양극소재 ··························································· 14
• 2.2.3 올리빈계 양극소재 ························································· 17
• 3. 제조방법 ······································································· 21
• 3.1 공침법 ········································································· 19
• 3.2 수열합성법 ··································································· 22
• 3.3 졸겔법 ········································································ 23
• 3.4 고온고상법 ··································································· 24
• 4. 실험방법 ······································································ 26
• 4.1 전구체 Ni0.83Co0.12Mn0.05(OH)2 제조 ····································· 26
• 4.2 양극 활물질 제조 ·························································· 27
• 4.2.1 Li[Ni0.83Co0.12Mn0.05]O2 제조 ·············································· 27
• 4.2.2 이종 원소 첨가에 따른 Li[Ni0.83o0.12Mn0.05]O2 제조 ·················· 27
• 4.3 전기화학적 측정을 위한 전극 제조 및 전지 조립 ··············· 28
• 4.3.1 전극 제조 ·································································· 28
• 4.3.2 전지 조립 ································································ 29
• 5. 분석방법 ····································································· 30
• 5.1 주사전자현미경(Scanning Electron Microscope, SEM) ····· 30
• 5.2 X-선 회절 분석(X-ray Diffraction, XRD) ······················· 30
• 5.3 주사 투과 전자 현미경 (Scanning Transmission Electron Microscope) ···············································································30
• 5.4 전기화학적 특성 평가 ··················································· 31
• 6. 결과 및 토의···················································· 32
• 6.1 물리적 특성 평가 ························································ 32
• 6.1.1 첨가된 Ca의 양에 따른 입자 형태 및 조성 분석 ··························· 32
• 6.1.2 분위기 및 첨가된 Ca의 양에 따른 XRD 분석 ······························ 36
• 6.1.3 조성에 따른 양이온 혼합 여부 분석 ······························ 40
• 6.2 전기화학적 특성 평가 ··················································· 42
• 7. 결론 ··········································································· 45
• 8. 참고문헌 ···································································· 46
• 9. ABSTRACT ································································ 49