Artificial Post‐Cycled Structure Modulation Towards Highly Stable Li‐Rich Layered Cathode

Abstract

AbstractHigh‐capacity Li‐rich layered oxides (LLOs) suffer from severe structure degradation due to the utilization of hybrid anion‐ and cation‐redox activity. The native post‐cycled structure, composed of progressively densified defective spinel layer (DSL) and intrinsic cations mixing, is deemed as the hindrance of the rapid and reversible de/intercalation of Li+. Herein, the artificial post‐cycled structure consisting of artificial DSL and inner cations mixing is in situ constructed, which would act as a shield against the irreversible oxygen emission and undesirable transition metal migration by suppressing anion redox activity and modulating cation mixing. Eventually, the modified DSL‐2% Li‐rich cathode demonstrates remarkable electrochemical properties with a high discharge capacity of 187 mAh g−1 after 500 cycles at 2 C, and improved voltage stability. Even under harsh operating conditions of 50 °C, DSL‐2% can provide a high discharge capacity of 168 mAh g−1 after 250 cycles at 2 C, which is much higher than that of pristine LLO (92 mAh g−1). Furthermore, the artificial post‐cycled structure provides a novel perspective on the role of native post‐cycled structure in sustaining the lattice structure of the lithium‐depleted region and also provides an insightful universal design principle for highly stable intercalated materials with anionic redox activity.