1：Experimental Design and Method Selection:

The study utilized a confocal Raman microscope Alpha 300 AR with a 633-nm He-Ne laser source for Raman spectra measurements. The methodology focused on statistical/big-data approach by performing multiple scans/mappings to analyze the phase transformation kinetics.

2：Sample Selection and Data Sources:

Pristine LiFePO4 powder samples were synthesized via a solid-state procedure and characterized solely by Raman spectroscopy to avoid the influence of other characterization techniques.

3：List of Experimental Equipment and Materials:

Confocal Raman microscope Alpha 300 AR (WiTec GmbH), 633-nm He-Ne laser, 100× lens with NA = 0.75, laser power and energy meter Vega with photodiode laser sensor PD300R-3W (Ophir Photonics Group).

4：75, laser power and energy meter Vega with photodiode laser sensor PD300R-3W (Ophir Photonics Group). Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: The probing laser power was varied from 1.6 to 4.8 mW, with each scan consisting of 100 Raman spectra. Optical images were taken before and after each scan to monitor decomposition.

5：6 to 8 mW, with each scan consisting of 100 Raman spectra. Optical images were taken before and after each scan to monitor decomposition. Data Analysis Methods:

5. Data Analysis Methods: Statistical analysis of Raman spectra to determine the decomposition probability and phase transformation kinetics.