Ultrastable Lithium‐Rich Cathodes Enabled by Coherent Surface Engineering

The irreversible interfacial side reactions of lithium‐rich layered oxides at high voltage lead to deterioration of cycling performance. Herein, we construct a Ce 3+ ‐rich surface layer on the lithium‐rich layered oxides surface. Owing to the strong chemical affinity between rare‐earth elements and oxygen, the Ce‐rich spinel surface layer is completely encapsulated around the lithium‐rich layered oxides particles. Also, an excess of Ce 3+ leads to the formation of Li x CeO 2− y nanoparticles, which are adorned on the surface layer. This surface modification lowers the work function, promoting the formation of a thin, inorganic‐rich, and uniform cathode–electrolyte interphase. Consequently, this layer mitigates the dissolution of transition metals and enhances the stability of the surface lattice oxygen. Consequently, the LLO@Ce cathode demonstrates a high‐capacity retention of 93.12% at 1 C after 500 cycles. This work presents a promising path for stabilizing the surface of lithium‐rich layered oxides, thereby enhancing its cycling performance for high‐energy‐density lithium‐ion batteries.