1：Experimental Design and Method Selection:

Solution cast method was employed to fabricate binary BT/PVDF and ternary BT/MXene/PVDF nanocomposite films. The design rationale was to use low-concentration fillers to avoid agglomeration and improve interface compatibility.

2：Sample Selection and Data Sources:

Barium titanate (BT) nanoparticles with average size of 100 nm, titanium carbide MXene nanosheets, and polyvinylidene fluoride (PVDF) were used as materials. Weight concentrations of BT were varied from 0 to 8 wt%, and MXene was fixed at 2 wt%.

3：List of Experimental Equipment and Materials:

Materials included BT powder (Aladdin), MXene powder (Shanghai Bohan Chemical Technology Co., Ltd.), PVDF powder (Solvay), and DMF solvent (Tianjin Chemical Reagent Co., Ltd.). Equipment included ultrasonicator, magnetic stirrer, oven, LCR meter (HP4284A, Agilent), auto voltage withstanding tester (RK2674B), ferroelectric analyzer (Premiere ??, Radiant), and coater (JEOL JFC-1600).

4：0). Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Fillers were dispersed in DMF via ultrasonication and stirring, mixed with PVDF solution, stirred for 20 h, cast on glass slides, dried at 70°C, annealed at 180°C for 8 h under reduced pressure, and gold electrodes were sputtered for measurements.

5：Data Analysis Methods:

Dielectric properties were measured using an LCR meter from 100 Hz to 1 MHz, breakdown strength was measured with a voltage tester, and data were analyzed for permittivity, loss, conductivity, and breakdown strength trends.