Zinc-Doped\nHigh-Nickel, Low-Cobalt Layered Oxide Cathodes\nfor High-Energy-Density Lithium-Ion Batteries

Abstract

High-Ni layered oxides with Ni contents\ngreater than 90% are promising\ncathode candidates for high-energy-density Li-ion batteries. However,\ndrastic electrode–electrolyte reactions and mechanical degradation\nissues limit their cycle life and practical viability. We demonstrate\nhere that LiNi_0.94Co_0.04Zn_0.02O_1.99 (NCZ), obtained by incorporating 2 mol % Zn²⁺ into an ultrahigh-Ni baseline cathode material LiNi_0.94Co_0.06O₂ (NC), delivers superior cell performance.\nNCZ retains 74% of the initial capacity after 500 cycles in a full\ncell assembled with a graphite anode, outperforming NC (62% retention).\nNCZ also possesses a higher average discharge voltage relative to\nNC with an outstanding average voltage retention of over 99% after\n130 cycles in half cells. Bulk structural investigations unveil that\nZn doping promotes a smoother phase transition, suppresses anisotropic\nlattice distortion, and maintains the mechanical integrity of cathode\nparticles. Furthermore, NCZ shows an enhanced interphase stability\nafter long-term cycling, in contrast to the seriously degraded surface\nchemistry in NC. This work provides a practically viable approach\nfor designing higher-energy-density high-Ni layered oxide cathodes\nfor lithium-ion batteries.