Incorporating Lithium-Deficient Layer and Interfacial-Confined Catalysis Enables the Reversible Redox of Surface Oxygen Species in Lithium-Rich Manganese-based Oxides

Abstract

Lithium-rich manganese-based oxides (LRMO) are a promising next-generation candidate cathode material, offering a high discharge capacity exceeding 300 mAh g−1. This exceptional capacity is attributed to the synergistic redox activity of transition metals and lattice oxygen. Nevertheless, the over-oxidation of lattice oxygen in LRMO leads to capacity fading, severe lattice strain, and sluggish oxygen redox reaction kinetics. Herein, we introduce a lithium-deficient layer and a RuO2-promoted interface-confined catalysis network on the surface of LRMO (Ru-1). The lithium-deficient layer effectively passivates the surface lattice oxygen by reducing the Li-O-Li configurations at the atomic level. The RuO2-promoted interface-confined catalysis network successfully captures trace amounts of lost lattice oxygen and catalyzes the reversible reduction of activated O species. This configuration yields a specific discharge capacity of 307 mAh g−1 at 0.1 C, with an impressive capacity retention rate of 97% after 300 cycles at 1 C. The Ru-1||graphite pouch cell exhibits a superior capacity retention rate of 85% after 450 cycles at C/3 and the Ru-1||Li pouch cell exhibits a high energy density of 513 Wh kg−1. Our strategies involving the lithium-deficient layer and interface-confined catalysis offer novel insights into protecting the surface and enhancing oxygen reusability within the LRMO.