Related Experiment Video
Updated: Aug 6, 2026
07:26
Synthesis and Microdiffraction at Extreme Pressures and Temperatures
Published on: October 7, 2013
Monitoring the Microwave Synthesis of d0-Free Disordered Rocksalt Cathodes Using In Situ Infrared Pyrometry
Erick A Lawrence1, Matthew A Wright1, Tianyu Li1,2
1Materials Department and Materials Research Laboratory, University of California Santa Barbara, Santa Barbara, California, USA.
Angewandte Chemie (International Ed. in English)
|August 5, 2026
Summary
Understanding microwave synthesis of disordered rocksalt oxides (DRX) is key for battery materials. This study reveals a reentrant order-disorder-order pathway for Li-Mn-O-F, showing precise control is needed for pure DRX phase formation.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Inorganic Synthesis
Background:
- Solid-state reaction pathways are crucial for linking predictive models with experimental synthesis.
- Microwave synthesis offers a powerful route for inorganic materials, but its mechanisms, especially for metastable phases, are poorly understood.
- Disordered rocksalt oxides (DRX) are metastable phases of interest for next-generation Li-ion cathodes.
Purpose of the Study:
- To investigate the microwave reaction pathway of Li1.1Mn0.9O1.9F0.1, a disordered rocksalt oxide.
- To understand the formation mechanism of DRX phases under microwave heating.
- To correlate phase purity with electrochemical performance for Li-ion cathode applications.
Main Methods:
- Ex situ X-ray diffraction and solid-state Nuclear Magnetic Resonance (NMR) for phase identification.
- In situ infrared thermography to monitor reaction temperatures and transitions.
- Electrochemical cycling to evaluate the performance of synthesized materials.
Main Results:
- The reaction proceeds via a reentrant order-disorder-order transformation.
- Layered Li-Mn-O intermediates disorder above 945°C to form the DRX phase, and reorder upon further heating.
- Infrared thermography identified a distinct feature indicating the completion of the disordering transition, allowing for precise reaction control.
- Residual layered phases minimally impacted electrochemical performance, despite the DRX phase being stable only near 945°C.
Conclusions:
- Microwave synthesis of Li1.1Mn0.9O1.9F0.1 involves a temperature-sensitive reentrant phase transformation.
- Precise control of microwave heating duration is essential to maximize the purity of the desired disordered rocksalt oxide phase.
- The electrochemical performance of Li-ion cathodes is tolerant to minor amounts of residual layered phases, broadening the viable synthesis window.
