Journal of the Korean Electrochemical Society (전기화학회지)

The Korean Electrochemical Society (한국전기화학회)
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Enhanced Cycle Performance of Bi-layer Structured LMO-NCM Positive Electrode at Elevated Temperature

겹층구조의 LMO-NCM 복합양극을 통한 고온 사이클 수명개선 연구

  • Yoo, Seong Tae (Department of Chemical Engineering and Biotechnology, Tech University of Korea) ;
  • Ryu, Ji Heon (Graduate School of Knowledge-based Technology and Energy, Tech University of Korea)
  • 유성태 (한국공학대학교 생명화학공학과) ;
  • 류지헌 (한국공학대학교 지식기반기술.에너지대학원)
  • Received : 2022.11.13
  • Accepted : 2022.11.17
  • Published : 2022.11.30
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Abstract

Spinel LiMn2O4 (LMO) and layered LiNi0.5Co0.2Mn0.3O2 (NCM) are widely used as positive electrode materials for lithium-ion batteries. LMO and NCM positive electrode materials have a complementary properties. LMO has low cost and high safety and NCM materials show a relatively high specific capacity and better cycle life even at elevated temperature. Therefore, the LMO and NCM active materials are blended and used as a positive electrode in large-size batteries for electric vehicles (xEV). In this study, the cycle performance of a blended electrode prepared by simply mixing LMO and NCM and a bi-layer electrode in which two electrode layers aree sequentially coated are compared. The bi-layer electrode prepared by composing the same ratio of both active materials has similar capacity and cycle performance to the blend electrode. However, the LN electrode coated with LMO first and then NCM is the best in the full cell cycle performance at elevated temperature, and the NL electrode, in which NCM is first coated with LMO has a faster capacity degradation than the blended electrode because LMO is mainly located on the top of the electrode adjacent to electrolyte and graphite negative electrode. Also, the LSTA (linear sweep thermmametry) analysis results show that the LN bi-layer electrode in which the LMO is located inside the electrode has good thermal stability.

스피넬 구조의 LiMn2O4 (LMO) 및 층상구조의 LiNi0.5Co0.2Mn0.3O2 (NCM)는 리튬이온 이차전지의 양극 활물질로 널리 사용되어 왔다. 가격이 저렴하고 안전성이 우수한 LMO와 용량이 크고 고온 수명이 유리한 NCM 양극 물질은 상호 보완적인 특성을 가지고 있어, 두 활물질을 혼합하여 특히 hybrid electric vehicle (HEV)를 포함한 중대형 전지 등에서 양극으로 채택되어 사용되고 있다. 본 연구에서는 LMO와 NCM으로 구성된 복합전극을 제조할 때, 이를 단순히 혼합하여 제조한 blend 전극과 두 전극을 겹층구조로 제조한 전극의 수명특성을 비교하였다. 두 활물질의 비율을 모두 1:1로 구성하여 제조한 겹층전극은 blend 전극과 유사한 용량 및 동등한 사이클 수명을 지니고 있었다. 그리고, 완전지의 고온 사이클에서는 LMO를 먼저 코팅하고 나서 NCM을 코팅한 LN 전극이 가장 우수하였으며, NCM을 먼저 코팅하고 LMO를 다음에 코팅한 NL 전극은 표면에 LMO가 주로 위치하면서 blend 전극보다 오히려 용량퇴화가 더 빠르게 진행되었다. 또한, LSTA (linear sweep thermmametry) 분석결과에서도 LMO가 주로 전극내부에 위치한 LN 겹층전극의 열적 안정성이 보다 우수하였다.

Keywords

Acknowledgement

이 연구는 2022년도 산업통상자원부 및 산업기술평가관리원(KEIT) 연구비 지원(20017477, 소재부품기술개발사업) 및 2022년도 정부(산업통상자원부)의 재원으로 한국산업기술진흥원의 지원(P0002007, 2022년 산업혁신인재성장지원사업)을 받아 수행된 연구임.

References

  1. T.-H. Kim, J.-S. Park, S. K. Chang, S. Choi, J. H. Ryu, and H.-K. Song, The current move of lithium ion batteries towards the next phase, Adv. Energy Mater., 2(7), 860 (2012). https://doi.org/10.1002/aenm.201200028
  2. J. M. Tarascon and M. Armand, Issues and challenges facing rechargeable lithium batteries, Nature, 414, 359 (2001). https://doi.org/10.1038/35104644
  3. G.-W. Lee, J.-H. Lee, J. H. Ryu, and S. M. Oh, Improvement of high-temperature performance of LiMn2O4 cathode by surface coating, J. Kor. Electrochem. Soc., 12(1), 81 (2009). https://doi.org/10.5229/JKES.2009.12.1.081
  4. D. H. Jang, Y. J. Shin, and S. M. Oh, Dissolution of spinel oxides and capacity losses in 4 V Li/LixMn2O4 cells, J. Electrochem. Soc., 143, 2204 (1996). https://doi.org/10.1149/1.1836981
  5. Y. Y. Xia, Y. H. Zhou, and M. Yoshio, Capacity fading on cycling of 4 V Li/LiMn2O4 cells, J. Electrochem. Soc., 144, 2593 (1997). https://doi.org/10.1149/1.1837870
  6. A. J. Smith, S. R. Smith, T. Byrne, J. C. Burns, and J. R. Dahn, Synergies in blended LiMn2O4 and Li[Ni1/3Mn1/3Co1/3]O2 positive electrodes, J. Electrochem. Soc., 159, A1696 (2012). https://doi.org/10.1149/2.056210jes
  7. D. Wu, H. Ren, Y. Guo, X. Zhang, Z. Zhang, and J. Li, Synergetic effects of LiNi1/3Co1/3Mn1/3O2-LiMn2O4 blended materials on lithium ionic transport for power performance, Ionics, 25, 595 (2019).
  8. S. B. Chikkannanavar, D. M. Bernardi, and L. Liu, A review of blended cathode materials for use in Li-ion batteries, J. Power Sources, 248, 91 (2014). https://doi.org/10.1016/j.jpowsour.2013.09.052
  9. D. Ren, L. Lu, M. Ouyang, X. Feng, J. Li, and X. Han, Degradation identification of individual components in the LiyNi1/3Co1/3Mn1/3O2-LiyMn2O4 blended cathode for large format lithium ion battery, Energy Procedia, 105, 2698 (2017). https://doi.org/10.1016/j.egypro.2017.03.919
  10. C. Huang, N. P. Young, J. Zhang, H. J. Snaith, P. S. Grant, A two layer electrode structure for improved Li Ion diffusion and volumetric capacity in Li Ion batteries, Nano Energy, 31, 377 (2017). https://doi.org/10.1016/j.nanoen.2016.11.043
  11. M. Wood, J. Li, Z. Du, C. Daniel, A. R. Dunlop, B. J. Polzin, A. N. Jansen, G. K. Krumdick, and D. L. Wood III, Impact of secondary particle size and two-layer architectures on the high-rate performance of thick electrodes in lithium-ion battery pouch cells, J. Power Sources, 515, 230429 (2021). https://doi.org/10.1016/j.jpowsour.2021.230429
  12. H. Kang, Y. M. Kim, B. K. Park, J. H. Yang, S. Jeong, K. J. Kim, and J. Mun, Effective dual-layer fabrication solution for the lateral axial failure of the electrode in lithium-ion batteries, Int. J. Energy Res., in press. DOI: 10.1002/er.8694