Triboelectric nanogenerators (TENGs) offer new avenues for the development of sustainable energy conversion and self-powered smart devices, where new triboelectric materials with high dielectric constant may be the key for enhancing the surface charge density and output. In this study, different concentrations of barium titanate (BTO) nanoparticles are introduced into the polycarbonate (PC) matrix using the phase inversion technique. A high-performance TENG (PB-TENG) was then developed with a power density of 436 mW/m2 using the as-synthesized PC/BTO composite film as the positive triboelectric electrode material. Compared to PB-TENG at 0% BTO doping, the peak power density was increased by 153%. This enhancement of power output should be attributed to the synergistic effect of increased dielectric constant and surface roughness of the composite film. The Arrayed-Smart Bracelet (A-SB) is designed for health monitoring and motion recognition in swimming, offering high sensitivity, stability, and selectivity for self-powered water sports safety monitoring.