In situ Crystal Structure Growth and Control for Enhancing Comprehensive Performance in Ultra-High Nickel-Layered...

The ultra-high nickel-layered cathodes, LiNi_xCo_yMn_{1- x - y}O₂ (x ≥ 0.9), featuring high energy density and low cost, have been the exploration and application targets for the next-generation batteries. Current ultra-high nickel cathodes fail to meet the commercial demands, owing to the structure degradation during cycle. Additionally, the dense structure of traditional secondary particles restricts the migration of Li⁺ and further limits the capacity and rate performance. In this work, we focus on modulating intrinsic structure and morphology of cathodes originating from in situ growth method and have further controllably synthesized a special ultra-high nickel cathode with gapped structure and thin surface rock-salt phase (G-Ni91). Compared to the traditional dense-structure cathode (D-Ni91), G-Ni91 delivers better performance in all aspects, whether it is initial capacity, cycle stability, rate performance, high-voltage operation, and high-temperature condition. Multiscale characterizations manifests that smaller primary particle size, gapped interspace and less Li⁺/Ni²⁺ antisite in G-Ni91 supply enhanced Li⁺ transport dynamics. Moreover, the thin surface rock-salt phase and more uniform primary particles are regarded as contributions to the improved cycling stability. This work provides a feasible original intrinsic structural design and modification from precursor to cathodes, ultimately facilitating substantial improvements in electrochemical performance of ultra-high nickel-layered cathodes.