A General Spatial-Confinement Strategy for Atomic-Level Engineering of Single-Crystal Li-Rich Manganese-Based Oxides

The commercialization of Li-rich manganese-based oxides (LRMOs) is stymied by intractable voltage decay and sluggish kinetics, stemming from the inherent challenge of achieving atomic-level stoichiometric precision via conventional co-precipitation or solid-state methods. Herein, a versatile and scalable one-step acetate-precursor-facilitated spray pyrolysis strategy is reported for the atomic-level engineering of O3-type single-crystalline Li_1.194Ni_0.123Co_0.131Mn_0.560O₂ (denoted as Li-1.38). Within the spatially confined "microreactor" formed by spray droplets, atomic-scale homogenization is achieved, ensuring precise stoichiometry while predefining the homogeneous dispersion of Mn and Ni to synergistically boost capacity and reinforce structural stability. Concurrently, this strategy precisely orchestrates the LiTMO₂/Li₂MnO₃ phase equilibrium and maximizes the Mn⁴⁺ fraction to facilitate the formation of robust LiMn₆ honeycomb superlattices. This optimized structural ordering elevates the thermodynamic barrier for oxygen vacancy formation and mitigates Li⁺/Ni²⁺ cation mixing, as corroborated by distribution of relaxation times (DRT) and density functional theory (DFT) calculations. Consequently, the pristine Li-1.38 cathode exhibits an exceptional initial capacity (246.29 mAh·g^-1 at 0.1 C), along with inhibited phase transformations and expedited Li⁺ transport kinetics (D_Li+ ≈ 2.28 × 10^-9 cm²·s^-1). This work establishes the atomistic structure-performance correlations and provides a scalable paradigm for the continuous manufacturing of high-energy-density LRMOs.