Gas–solid interfacial modification of oxygen activity in layered oxide cathodes for lithium-ion batteries

TLDR

Lattice oxygen influences electrochemical processes by affecting structural stability and electron/ion transport in high‑capacity oxide cathodes for Li‑ion batteries. The study aims to design a gas–solid interface reaction to precisely control oxygen activity in Li‑rich layered oxides. The authors achieve this by uniformly creating oxygen vacancies via a gas–solid interface reaction while preserving structural integrity. Theoretical calculations and experimental characterizations show that oxygen vacancies create a favorable ionic diffusion environment, suppress surface gas release, and enable a discharge capacity of 301 mAh g⁻¹ with 93.2 % initial Coulombic efficiency, maintaining 300 mAh g⁻¹ after 100 cycles without voltage decay, highlighting the design's effectiveness for next‑generation Li‑ion batteries.

Abstract

Abstract Lattice oxygen can play an intriguing role in electrochemical processes, not only maintaining structural stability, but also influencing electron and ion transport properties in high-capacity oxide cathode materials for Li-ion batteries. Here, we report the design of a gas–solid interface reaction to achieve delicate control of oxygen activity through uniformly creating oxygen vacancies without affecting structural integrity of Li-rich layered oxides. Theoretical calculations and experimental characterizations demonstrate that oxygen vacancies provide a favourable ionic diffusion environment in the bulk and significantly suppress gas release from the surface. The target material is achievable in delivering a discharge capacity as high as 301 mAh g −1 with initial Coulombic efficiency of 93.2%. After 100 cycles, a reversible capacity of 300 mAh g −1 still remains without any obvious decay in voltage. This study sheds light on the comprehensive design and control of oxygen activity in transition-metal-oxide systems for next-generation Li-ion batteries.