High-dielectric thin films are vital for charge storage in embedded capacitors. We report an efficient method using polystyrene@barium titanate (PS@BT) core-shell particles to prevent filler aggregation. 300 nm spherical PS particles were synthesized as templates to adsorb positively charged BT nanoparticles via electrostatic attraction. These arrays were drop-cast and thermally fused at 100℃ (near PS Tg). SEM confirmed uniform BT distribution without clustering. PS@BT-1, (55.6 wt% BT) achieved a dielectric constant of 30.9, a high breakdown voltage of 126 V/㎛, and an energy storage density of 2.17 J/㎤. PS@BT-2, (65.7 wt% BT) showed a higher dielectric constant of 36.2, though a leakage current percolation point was identified between these levels. This strategy offers a scalable route for high-performance dielectric layers in miniaturized electronics.