A paper by Dr. Yuta Fujii of Hokkaido University’s Faculty of Engineering has been published in RSC Mechanochemistry.
- Yuta Fujii, Masako Kakesu, Koji Ohara, Akira Miura, Kiyoharu Tadanaga. HCl-free mechanochemical synthesis of oxyhalide solid electrolyte LiNbOxCl(6−2x) using LiCl, NbCl5, and Nb2O5. RSC Mechanochemistry, 2026.
DOI: https://doi.org/10.1039/d6mr00010j
Abstract
The mechanochemical synthesis of LiNbOCl4 from NbCl5 and LiOH generates HCl gas, which poses significant corrosion issues and hinders large-scale synthesis. Here, we report an HCl-free mechanochemical synthesis of the LiNbOCl4 system using LiCl, NbCl5, and Nb2O5 as a strategic oxygen source, which can expand the flexibility in compositional design. This approach enabled the synthesis of LiNbOxCl(6−2x) (x = 0, 0.5, 0.8, 1.0, 1.2, 2.0, and 2.5) with different anion ratios. The resulting materials were systematically evaluated to understand the influence of the anion composition (O2− and Cl−) on the structure and Li+ conductivity. In addition, the thermal stability of the oxychloride system was also investigated under opened-system conditions, without the use of evacuated quartz tubes. In the X-ray diffraction (XRD) patterns of the compositions of x = 0.8, 1.0 and 1.2, the LiNbOCl4 phase was detected, and the x = 1.0 composition showed the highest Li+ conductivity of 4.3 mS cm−1. However, the LiNbOCl4 phase was unstable at the high temperature (≥100 °C), and the Li+ conductivity decreased to 2.6 mS cm−1 after heating at 100 °C. Higher heat treatment (200 and 300 °C) resulted in the decomposition of the LiNbOCl4 phase.
Visual Abstract
Credit: Fujii et al., RSC Mechanochemistry (2026), https://doi.org/10.1039/D6MR00010J. Licensed under CC BY 4.0