| 학회 | 한국재료학회 |
| 학술대회 | 2021년 가을 (11/24 ~ 11/26, 경주 라한호텔) |
| 권호 | 27권 2호 |
| 발표분야 | 특별심포지엄 1. 차세대 이차전지 소재기술 심포지엄-오거나이저: 김종순(성균관대), 류원희(숙명여대) |
| 제목 | Realizing high voltage operation of LiNiO2 cathode for lithium-ion batteries |
| 초록 | Single Ni component layered oxide of LiNiO2(LNO) developed in the 1990s is one of the most promising layered-type cathode because it can release a capacity close to the theoretical value (~ 240 mAh g-1)[1], fully satisfying the criteria for electric vehicles application with both specific (~800 Wh kg-1) and volumetric (2600 Wh l-1) energy densities. Moreover, since LNO addresses the cost and ethical-related issues simultaneously by removing cobalt element from its chemistry[2, 3], LNO is regarded as a genuinely sustainable cathode for next-generation LIBs. However, despite the vast merits, its clear drawbacks impede commercialization over the past 30 years. The most urgent issue of LNO is its desperate cycle retention with increasing operation voltage. According to the previous reports, cycle retention of LNO after 100 cycles at 0.5 C is less than 75 % of the initial capacity of 230 mAh g-1 with a 4.3 V cut-off. Meanwhile, the 4.1 V cycling shows a 95 % cycle retention but lower initial capacity of 180 mAh g-1 [4]. The origin of the high voltage degradation in layered oxide is not merely caused by a single element, but by a complex entanglement of mechanical and chemical factors[3, 5]. The multi-phase transitions[6], large lattice parameter changes[4], electrochemical creep[7] and internal fatigue from surface reconstruction[8] lead to the mechanical cracks or particle isolation, and eventually causing capacity fade. The secondary particle morphologies have been widely adapted to secure the high tap density and increase the power density of Ni-rich layered oxide. Still, this structure quickly generates intergranular cracking from the aforementioned factors. Chemical degradations, such as transition metal dissolution[9], singlet oxygen evolution[10], and Ni ion migration[11] are in charge of reducing the surface electrochemical activity[12], which continuously occur during cycling due to the mechanical damage that creates a new surface. Despite these previous efforts and understandings, the realization of cycling LNO over 4.3 V or Ni-rich oxide with even a higher voltage over ultrahigh voltage 4.6V still remains a challenge because of the destructive oxygen stacking transition that appears at highly delithiated phases, losing their electrochemical activities more rapidly[13, 14]. In this talk, we will discuss the high voltage degradation mechanism of LNO with respect to the oxygen stacking structural evolution. It is revealed that the local oxygen stacking change from O3 into O1 sequence in the high voltage can occur prematurely due to the loss of lattice oxygen, following the formation of NiLi defects in O1-type structure that induces the irreversible stacking fault[15]. Since these structural evolutions accelerate serious mechanical degradation in a primary particle due to its crystal structure incoherency, it can rapidly reduce the electrochemical activity of LNO. This conclusion guides that the key solution for realizing high voltage operation is to suppress the oxygen evolution from the surface, thus mitigating the destructive oxygen stacking transition. This degradation cascade model suggests new insight on the oxygen stacking chemistry of Ni-rich layered oxide toward achieving high energy density LIBs. References 1. J. R. Dahn, U. von Sacken and C. A. Michal, Solid State Ionics, 1990, 44, 87-97. 2. C. Banza Lubaba Nkulu, L. Casas, V. Haufroid, T. De Putter, N. D. Saenen, T. Kayembe-Kitenge, P. Musa Obadia, D. Kyanika Wa Mukoma, J.-M. Lunda Ilunga, T. S. Nawrot, O. Luboya Numbi, E. Smolders and B. Nemery, Nat. Sustain., 2018, 1, 495-504. 3. W. Li, E. M. Erickson and A. Manthiram, Nat. Energy, 2020, 5, 26-34. 4. C. S. Yoon, D.-W. Jun, S.-T. Myung and Y.-K. Sun, ACS Energy Lett., 2017, 2, 1150-1155. 5. M. Bianchini, M. Roca-Ayats, P. Hartmann, T. Brezesinski and J. Janek, Angew. Chem. Int. Ed., 2019, 58, 10434-10458. 6. L. de Biasi, A. Schiele, M. Roca-Ayats, G. Garcia, T. Brezesinski, P. Hartmann and J. Janek, ChemSusChem, 2019, 12, 2240-2250. 7. Y. Bi, J. Tao, Y. Wu, L. Li, Y. Xu, E. Hu, B. Wu, J. Hu, C. Wang, J.-G. Zhang, Y. Qi and J. Xiao, Science, 2020, 370, 1313-1317. 8. C. Xu, K. Märker, J. Lee, A. Mahadevegowda, P. J. Reeves, S. J. Day, M. F. Groh, S. P. Emge, C. Ducati, B. Layla Mehdi, C. C. Tang and C. P. Grey, Nat. Mater., 2020, DOI: 10.1038/s41563-020-0767-8. 9. S. H. Song, M. Cho, I. Park, J.-G. Yoo, K.-T. Ko, J. Hong, J. Kim, S.-K. Jung, M. Avdeev, S. Ji, S. Lee, J. Bang and H. Kim, Adv. Energy Mater., 2020, 10, 2000521. 10. J. Wandt, A. T. S. Freiberg, A. Ogrodnik and H. A. Gasteiger, Mater. Today, 2018, 21, 825-833. 11. F. Kong, C. Liang, L. Wang, Y. Zheng, S. Perananthan, R. C. Longo, J. P. Ferraris, M. Kim and K. Cho, Adv. Energy Mater., 2019, 9, 1802586. 12. J. Xu, E. Hu, D. Nordlund, A. Mehta, S. N. Ehrlich, X.-Q. Yang and W. Tong, ACS Appl. Mater. Interfaces, 2016, 8, 31677-31683. 13. J. Yang and Y. Xia, ACS Appl. Mater. Interfaces, 2016, 8, 1297-1308. 14. T. Ohzuku, A. Ueda and M. Nagayama, J. Electrochem. Soc., 1993, 140, 1862-1870. 15. K.-Y. Park, Y. Zhu, C. G. Torres-Castanedo, H. J. Jung, N. S. Luu, O. Kahvecioglu, Y. Yoo, J.-W. T. Seo, J. R. Downing, H.-D. Lim, M. J. Bedzyk, C. Wolverton, M. C. Hersam, submitted |
| 저자 | 박규영1, Mark Hersam2 |
| 소속 | 1POSTECH, 2Northwestern Univ. |
| 키워드 | <P>Li-ion batteries; Cathode; Co-free; LiNiO2; High voltage</P> |
