1：Experimental Design and Method Selection:

The study used a downstream tubular inductively-coupled RF plasma reactor for PECVD processing of graphite micropowder. The reactor design included a glass plasma tube, water cooling, RF power generation, vacuum system, and powder feeding. The powder was reprocessed 6 times to achieve a continuous coating. Characterization methods included FIB-SEM for imaging, Raman spectroscopy and XPS for chemical analysis, and flowability testing.

2：Sample Selection and Data Sources:

Synthetic graphite micropowder (TIMREX? KS5–25, 15 μm average particle diameter) was used. Data were obtained from direct experimental measurements on processed and native graphite samples.

3：List of Experimental Equipment and Materials:

Equipment included a downstream tubular plasma reactor, FIB-SEM (Zeiss NVision 40), Raman spectrometer (inVia Raman microscope, Renishaw), XPS (SIGMA Probe 2, Thermo Fisher), and ring shear tester (RST-XS, Schulze Schüttguttechnik). Materials included argon gas (PanGas), HMDS (Sigma-Aldrich), and graphite micropowder.

4：Experimental Procedures and Operational Workflow:

The reactor was evacuated to 3 Pa, then fed with a 1:1 Ar/HMDS mixture at 500 sccm and 150 Pa pressure. Plasma was ignited at 1200 W. Graphite powder was fed at 0.6 kg/h, with a residence time of ~0.1 s. After each run, the powder was collected and reprocessed. For characterization, samples were prepared and analyzed using FIB-SEM (milling and imaging), Raman spectroscopy (laser excitation at 514 nm), XPS (Al Kα source), and flowability testing (shear stresses applied).

5：6 kg/h, with a residence time of ~1 s. After each run, the powder was collected and reprocessed. For characterization, samples were prepared and analyzed using FIB-SEM (milling and imaging), Raman spectroscopy (laser excitation at 514 nm), XPS (Al Kα source), and flowability testing (shear stresses applied). Data Analysis Methods:

5. Data Analysis Methods: XPS data were analyzed using CasaXPS software with Gaussian–Lorentzian line shape and Shirley background subtraction. Quantitative analysis considered Scofield photoionization cross sections. Raman spectra were acquired and compared to standards. Flowability factors were calculated from shear test repetitions.