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

High-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 & DEG;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.

Automated summary

High-capacity Li-rich layered oxides (LLOs) experience structure degradation due to hybrid anion- and cation-redox activity. A new artificial post-cycled structure is created to suppress anion redox activity and modulate cation mixing, resulting in improved electrochemical properties and voltage stability. The modified DSL-2% Li-rich cathode shows high discharge capacities even under harsh conditions, outperforming the pristine LLO. This artificial post-cycled structure provides insights into sustaining the lattice structure of lithium-depleted regions and designing stable intercalated materials with anionic redox activity.