Lithium-rich manganese-based cathode materials with highly stable lattice and surface enabled by perovskite-type phase-compatible layer

Li-rich Mn-based cathode materials possess a high specific capacity, but their application is hindered by inherent anion activity and surface instability. In this regard, a perovskite-type LaMnO3 modified layer was epitaxially grown on the surface of Li-rich Mn-based cathode through La reaction with Mn provided by bulk materials. XRD and XPS results confirmed the successful preparation of LaMnO3 and revealed the reaction mechanism. SEM and TEM results further verified the epitaxial growth and uniform distribution of LaMnO3. The modified Li-rich Mn-based cathode materials showed outstanding rate capability and satisfactory cycle durability, which exhibited 155.4 mAh g−1 at 5 C and maintained 85.4% at 1 C after 200 cycles during 2.0–4.8 V of operation. The anion activity (O2-, O22-) was effectively suppressed, resulting in more stable discharge voltage and enhanced initial coulomb efficiency. The surface of the cathode was protected by LaMnO3, leading to reduced surface by-products and fixed lattice O. The more stable lattice structures and high conductivity of LaMnO3 led to easy charge transfer and excellent electrochemical performance.