Heuristic Strategy for Achieving Long-Term Cycle Stability for Ni-Rich Layered Cathodes at Full Start of Charge

Abstract

The demand for energy sources with high energy densities continues to push the limits of Ni-rich layered oxides that are currently the most promising cathode materials in Li-ion batteries.1-3 Although most current research is focused on extending battery’s cycle life using Ni-rich layered cathodes,4 long-term cycling stability using a practical full cell is yet to be demonstrated. Here, we introduce Li[Ni0.90Co0.09Ta0.01]O2 which maintains 90% capacity retention after 2,000 cycles at full state of charge (SOC) with an energy density > 850 Wh kg−1. In contrast, the currently most sought-after Li[Ni0.90Co0.09Al0.01]O2 cathode loses ~40% of its initial capacity within 500 cycles at full SOC. Cycling stability is achieved by radially aligned primary particles with crystallographic texture toward the particle surface that effectively dissipate the internal strain occurring in the deeply charged state,5,6 while the substitution of Ni3+ withhigher valence ions induces ordered occupation of Ni ions in the Li slab and stabilizes the delithiated structure. Noh, H.-J., Youn, S., Yoon, C. S. & Sun, Y.-K. Power Sources 233, 121–130 (2013).Nam G. W. et al. ACS Energy Lett. 4, 2995–3001 (2019).Kim, U.-H. et al. Energy Environ. Sci. 11, 1271–1279 (2018).Woo, S.-U., Yoon, C. S., Amine, K., Belharouak, I. & Sun, Y.-K. Electrochem. Soc. 154, A1005–A1009 (2007).Park, K.-J. et al. Adv. Energy Mater. 8, 1801202 (2018).Ryu, H.-H. et al. Materials Today 36, 73–82 (2020).