1：Experimental Design and Method Selection:

The study uses a mathematical model of energy transfer in ball milling to investigate the effects of rotation speed, milling time, and BtPw ratio on RP to BP conversion. High-energy ball milling (HEBM) is employed as the synthesis method, with characterization via solid-state NMR, Raman spectroscopy, XRD, and SEM.

2：Sample Selection and Data Sources:

Commercial red phosphorus (Sigma-Aldrich, >97%) is used as the starting material. Samples are prepared with varying parameters: rotation speed (250-500 rpm), milling time (15-3240 min), and BtPw ratio (10:1 to 110:1). All handling is done in an Ar-filled glovebox to prevent oxidation.

3：1). All handling is done in an Ar-filled glovebox to prevent oxidation. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment includes a planetary ball milling apparatus (specific model not mentioned), Bruker D8 Advanced powder diffractometer for XRD, Zeiss EVO MA10 microscope for SEM, Bruker Avance III 400 MHz spectrometer for NMR, and Labram Dilor spectrometer for Raman spectroscopy. Materials include stainless steel bowls and balls, and commercial RP.

4：Experimental Procedures and Operational Workflow:

RP is weighed and placed in sealed stainless steel bowls with balls in a glovebox. Milling is performed at specified parameters. After milling, samples are characterized immediately using NMR, XRD, Raman, and SEM to analyze phase composition and morphology.

5：Data Analysis Methods:

XRD data are analyzed using intensity ratios of RP and BP reflections. NMR spectra are deconvolved using Gaussian and Lorentzian fits. Raman spectra are analyzed using peak intensities and fitting procedures. SEM images are used for morphological analysis.