Heuristic solution for achieving long-term cycle stability for Ni-rich layered cathodes at full depth of discharge

초록

The demand for energy sources with high energy densities continues to push the limits of Ni-rich layered oxides, which are currently the most promising cathode materials in automobile batteries. Although most current research is focused on extending battery life using Ni-rich layered cathodes, long-term cycling stability using a full cell is yet to be demonstrated. Here, we introduce Li[Ni0.90Co0.09Ta0.01]O2, which exhibits 90% capacity retention after 2,000 cycles at full depth of discharge (DOD) and a cathode 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 DOD. Cycling stability is achieved by radially aligned primary particles with [003] crystallographic texture that effectively dissipate the internal strain occurring in the deeply charged state, while the substitution of Ni3+ with higher valence ions induces ordered occupation of Ni ions in the Li slab and stabilizes the delithiated structure.

키워드