K₂CO₃ fibers synthesized via an evaporation-driven process exhibited a 10 times higher specific surface area (2.19 m²/g) than K₂CO₃ powder (0.25 m²/g), leading to significantly enhanced CO₂ adsorption performance. When incorporated into a PVDF-TrFE matrix, the composite film showed a 2 times increase in triboelectric output voltage and a 5 times enhancement in piezoelectric output compared to the pristine film. These improvements are attributed to the increased surface area and polarization induced by K₂CO₃, which facilitated the formation of the electroactive β-phase and improved dielectric properties. Overall, K₂CO₃ effectively serves as both a CO₂-adsorptive material and a functional filler that boosts the electroactive performance of PVDF-TrFE-based energy-harvesting systems.