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 Ce³⁺-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 Ce³⁺ leads to the formation of Li_xCeO_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.