Breaking the Vicious Spiral to Suppress Oxygen Loss in Li-Rich Oxide Cathode Materials.

Zhang, Zhenjie; Li, Yixin; Shen, Xi; Yang, Lu; Zhang, Chu; Liu, Yuan; Wang, Bowen; Kuo, Chang-Yang et al. · Adv Mater · 2025

basic_science · Level V

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Abstract

The irreversible oxygen loss (O-loss) hinders the application of oxygen redox (O-redox) cathode material in high-energy-density Li/Na-ion batteries. Although O-loss is commonly associated with O<sub>2</sub> release, the underlying mechanism remains unclear, which is not a simple surface problem. Herein, the O-loss/redox behaviors of the layered Li<sub>2</sub>MnO<sub>3</sub> and spinel Li<sub>4</sub>Mn<sub>5</sub>O<sub>12</sub> are comparatively investigated through experiments and density functional theory (DFT) calculations. It shows that the vicious spiral between O─O dimerization and Mn migration drive the void growth, chain-like structural collapse, and O<sub>2</sub> release in Li<sub>2</sub>MnO<sub>3</sub>. In contrast, the stable spinel framework and inert O in O-LiMn<sub>3</sub> coordination of Li<sub>4</sub>Mn<sub>5</sub>O<sub>12</sub> break this spiral and trap O<sub>2</sub> within the bulk, ensuring a reversible O-redox. By atomically compositing Li<sub>4</sub>Mn<sub>5</sub>O<sub>12</sub> with LiNi<sub>0.5</sub>Mn<sub>1.5</sub>O<sub>4</sub>, a novel Co-free Li-rich spinel oxide (LRSO) with high energy density (>1000 Wh kg<sup>-1</sup>) is produced. These findings clarify the correlation between structural rearrangement and O-redox and contribute to the design of advanced O-redox cathode materials.