Lithium-ion batteries now dominate electrochemical energy storage for vehicle propulsion and grid storage in addition to portable electronics. In 2022, they celebrate their 50^th anniversary, and yet still achieve only 25% of their theoretical energy density. The dominant anode and cathode today are graphitic carbon and the layered NMC oxides, LI[NiMnCoAl]O₂. Both need improving. Most of the carbon in the anode must go, and the NMCs need pushing to their limit and at the same time eliminating cobalt. I will today discuss the challenges faced as we push the limits of the NMCs to their limits, > 80% lithium cycling, and Ni>0.8 and Co <<0.1. The higher the Ni content the lower the charging voltage needed for a given cycling capacity, but the greater its surface and bulk reactivity. The issues discussed will include 1^stcycle loss [1], high rate capability [2], cathode stability [3], and surface/bulk reactivity and the impact of surface/bulk modification [4,5] and the micron-size single crystals vs meatballs on these [6]. This work is being supported by DOE-EERE-BMR-Battery500 consortium.

[1]. Hui Zhou, Fengxia Xin, Ben Pei, M. Stanley Whittingham, “What Limits the Capacity of Layered Oxide Cathodes in Lithium Batteries?”, ACS Energy Lett. 2019, 4: 1902−1906.

[2]. Chunmei Ban, Zheng Li, Zhuangchun Wu, Melanie J. Kirkham, Le Chen, Yoon Seok Jung, E. Andrew Payzant, Yanfa Yan, M. Stanley Whittingham, and Anne C. Dillon “Extremely Durable High-Rate Capability of a LiNi_0.4Mn_0.4Co_0.2O₂ Cathode Enabled by Single–Wall Carbon Nanotubes”, Advanced Energy Materials, 2011, 1: 58-62.

[3]. Hyung-Joo Noh, Sungjune Youn, Chong Seung Yoon, Yang-Kook Sun “Comparison of the structural and electrochemical properties of layered Li[Ni_xCo_yMn_z]O₂ (x = ¼ 1/3, 0.5, 0.6, 0.7, 0.8 and 0.85) cathode material for lithium-ion batteries”, J. Power Sources, 2013, 233: 121-130.

[4]. Fengxia Xin, Hui Zhou, Yanxu Zong, Mateusz Zuba, Yan Chen, Natasha A. Chernova, Jianming Bai, Ben Pei, Anshika Goel, Jatinkumar Rana, Feng Wang, Ke An, Louis F. J. Piper, Guangwen Zhou, and M. Stanley Whittingham, “What is the Role of Nb in Nickel-Rich Layered Oxide Cathodes for Lithium-Ion Batteries?”, ACS Energy Letters, 2021, 6: 1377-1382.

[5]. Ben Pei, Hui Zhou, Anshika Goel, Mateusz Zuba, Hao Liu, Fengxia Xin, and M. Stanley Whittingham, “Al Substitution for Mn during Co-Precipitation Boosts the Electrochemical Performance of LiNi_0.8Mn_0.1Co_0.1O₂”, J. Electrochemical Society, 2021, 68: 050532.

[6]. Yujing Bi, Jinhui Tao, Yuqin Wu, Linze Li, Yaobin Xu, Enyuan Hu, Bingbin Wu, Jiangtao Hu, Chongmin Wang, JiGuang Zhang, Yue Qi and Jie Xiao, “Reversible planar gliding and microcracking in a single-crystalline Ni-rich cathode”, Science, 2020, 370: 1313-1317.