Colloid‐Mediated Surface Reconstruction Through High‐Valence Element Integration Enables Stabilized Oxygen Redox and Fast Interfacial Kinetics in Li‐Rich Cathodes

ABSTRACT Lithium‐rich manganese‐based cathodes (LRM) deliver high discharge capacities beyond 250 mAh g −1 , but their practical deployment is restricted by irreversible oxygen redox, structural reconstruction, sluggish kinetics and unstable cathode‐electrolyte interfaces (CEI). Here, we develop a colloid‐assisted anchoring‐diffusion engineering strategy to simultaneously construct W 6+ surface‐gradient doping and an island‐like Li 2 WO 4 coating on Li 1.2 Ni 0.2 Mn 0.6 O 2 . Nano‐sized WO 3 , which is insoluble in isopropyl alcohol, is dispersed as a colloidal precursor and uniformly anchored onto the LRM surface via liquid‐phase adsorption and solvent‐mediated deposition. Subsequent calcination induces interfacial W 6+ diffusion into the near‐surface lattice while promoting the in situ formation of island‐like Li 2 WO 4 . Multiscale characterization and theoretical calculations reveal that W 6+ preferentially substitutes Mn sites in the Li 2 MnO 3 component, expands the interlayer spacing, strengthens W‐O bonding and raises the oxygen‐vacancy formation energy. These effects stabilize lattice oxygen, regulate anionic redox activity and mitigate irreversible phase transition. Meanwhile, the island‐like Li 2 WO 4 layer suppresses parasitic interfacial reactions, reduces charge‐transfer resistance and facilitates Li + transport. Benefiting from this coupled bulk‐surface regulation, the optimized W‐500 cathode delivers a high initial Coulombic efficiency of 85.99%, a capacity retention of 89.79% after 100 cycles at 1C, and a discharge capacity of 146.7 mAh g −1 at 5C. This work provides a scalable colloidal precursor route for integrating lattice stabilization with interfacial protection in high‐energy Li‐rich cathodes.