| 학회 | 한국재료학회 |
| 학술대회 | 2010년 봄 (05/13 ~ 05/14, 삼척 팰리스 호텔) |
| 권호 | 16권 1호 |
| 발표분야 | C. Energy and the Environment(에너지 및 환경재료) |
| 제목 | Structural Evolution of Layered Li1.2Ni0.2Mn0.6O2 upon Electrochemical Cycling in a Li Rechargeable Battery |
| 초록 | Recently Li1.2Ni0.2Mn0.6O2 has been consistently examined and investigated by scientists because of its high lithium storage capacity, which exceeds beyond the conventional theoretical capacity based on conventional chemical concepts. Consequently, Li1.2Ni0.2Mn0.6O2 is considered as one of the most promising cathode candidates for next generation in Li rechargeable batteries. Yet the mechanism and the origin of the overcapacity have not been clarified. Previously, many authors have demonstrated simultaneous oxygen evolution during the first delithiation. However, it may only explain the high capacity of the first charge process, and not of the subsequent cycles. In this work, we report a clarified interpretation of the structural evolution of Li1.2Ni0.2Mn0.6O2, which is the key element in understanding its anomalously high capacity. We identify how the structural evolution of Li1.2Ni0.2Mn0.6O2 occurs upon the electrochemical cycling through careful study of electrochemical profiles, ex-situ X-ray diffraction (XRD), HR-TEM, Raman spectroscopy, and first principles calculation. Moreover, we successfully separated the structural change at subsequent cycles (mainly cation rearrangement) from the first charge process (mainly oxygen evolution with Li extraction) by intentionally synthesizing sample with large particle size. Consequently, the intermediate states of structural evolution could be well resolved. All observations made through various tools lead to the result that spinel-like cation arrangement and lithium environment are created and embedded in layered framework during repeated electrochemical cycling. |
| 저자 | 홍지현, 서동화, 김성욱, 권혁조, 박영욱, 강기석 |
| 소속 | KAIST |
| 키워드 | Li rechargeable battery; Li-excess layered material; Li1.2Ni0.2Mn0.6O2; structural evolution; cathode |
