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

Abstract

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 LaMnO 3 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 LaMnO 3 and revealed the reaction mechanism. SEM and TEM results further verified the epitaxial growth and uniform distribution of LaMnO 3 . 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 (O 2- , O 2 2- ) was effectively suppressed, resulting in more stable discharge voltage and enhanced initial coulomb efficiency. The surface of the cathode was protected by LaMnO 3 , leading to reduced surface by-products and fixed lattice O. The more stable lattice structures and high conductivity of LaMnO 3 led to easy charge transfer and excellent electrochemical performance. • The lattice O is fixed and the migration of transition metal is well restricted by the La-O‐Mn bond. • The perovskite LaMnO 3 help in improving the electron transfer of charged particles and prevent the attacking of electrolytes. • Slightly La-doping regulates the Li/Ni disorder and stabilizes the crystal lattice, resulting in more stable structure.