Lithium-Ion

Understanding the Synthesis of Disordered Rock Salt DRX Disordered rock salt DRX) oxides and oxyfluorides represent a promising class of cathode materials due to their exceptional compositional flexibility, including Ni- and Co-free variants that achieve capacities exceeding 250 mAh/g. For systems containing Mn and Ti (such as Li1.1Mn0.8Ti0.1O1.9F0.1), the former serves as the primary redox-active species, while the latter plays a stabilizing role by accommodating local distortions within the lattice. In situ synchrotron X-ray diffraction XRD) reveals that DRX formation proceeds through multiple ordered rock-salt-related crystalline intermediates, beginning at 480 °C and homogenizing by 9501000 °C. Complementary ex situ X-ray absorption spectroscopy XAS) on quenched reaction intermediates show that Ti is incorporated into the DRX framework at lower temperatures than Mn 700 °C vs. 9501000 °C), highlighting how both in situ XRD and ex situ XAS are complementary measurement techniques to study the formation pathway of DRX.

Ti K-edge (a) Crystallographic structure of reaction intermediates (b) Weight fraction of precursors and intermediates formed during synthesis

Mn K-edge (a,b) Ti and Mn K-edge XAS spectra

Combining in-situ XRD during DRX synthesis with ex-situ XRD/XAS on quenched intermediates enables tracking of intermediate formation and final DRX framework, and reveals how temperature governs Transition Metal incorporation.

Source: Z. Liang et al 2025.

Extracted from the PDF; charts and images may read imperfectly.