Stabilization of a Highly Ni-Rich Layered Oxide Cathode through Flower-Petal Grain Arrays

Nickel adds to the capacity of layered oxide cathodes of lithium-ion batteries but comprises their stability. We report a petal-grained Li[Ni_0.89Co_0.10Sb_0.01]O₂ cathode that is, nevertheless, stable. The stability originates from the ordering of the nanosized grains in a dense, flower-petal-like array, where the elongated and nearly parallel grains radiate from the center to the surface. The ordering of the grains prevents microcrack generation from abrupt lattice changes of the stressful H2-H3 phase transition. The tight packing of the nanograins is conserved upon cycling, preventing destructive seepage of the electrolytic solution into the particles. The half-cell, cycling between 2.7-4.3 V versus Li/Li⁺ at a 0.5 C rate retains 95.0% of its initial capacity of 220 mAh g^-1 after 100 cycles. The full-cell, cycling with a graphite anode and between 3.0-4.2 V at a 1 C rate, retains 83.9% of its initial capacity after 1000 cycles.