Bi/K/La co-substituted BaTiO3 ceramic fillers for enhanced PDMS-based triboelectric nanogenerators

The limited dielectric response of PDMS triboelectric layers restricts the output performance and temperature stability of PDMS-based triboelectric nanogenerators (TENGs). Unlike conventional strategies that focus on introducing high-permittivity ceramic fillers or optimizing filler loading, this work regulates the intrinsic crystal structure and dielectric characteristics of BaTiO 3 -based ceramic fillers through compositional design. Bi/K/La co-substitution was employed to regulate the composition and dielectric response of BaTiO 3 -based ceramics with the composition Ba 1-x Bi 0.5x-0.02 K 0.5x La 0.02 TiO 3 (BBKLT, x = 0.2, 0.4, and 0.6), which were subsequently introduced as functional dielectric fillers into PDMS-based contact–separation-mode TENGs (CTENGs). XRD analysis shows that BBKLT-0.4 maintains good perovskite phase stability with reduced tetragonal distortion, and dielectric measurements further reveal a diffuse phase transition and frequency-dependent permittivity, indicating pronounced relaxor dielectric behavior. Comparison among the three compositions reveals that the CTENG output does not vary monotonically with either dielectric response or relaxor degree. Instead, BBKLT-0.4 exhibits a favorable balance among perovskite phase stability, relatively high dielectric response, low dielectric loss, and pronounced relaxor characteristics, corresponding to the highest device output. At 10 wt% filler content, the device achieves an open-circuit voltage of 156.14 V, a short-circuit current of 7.07 μA, and a maximum power density of about 476.2 mW/m 2 . It also maintains stable output over −10–60 °C and responds well to low-frequency excitation. In addition, it can light 60 LEDs and power a calculator after rectification and storage. These results extend the conventional filler-loading optimization strategy toward the intrinsic structure–dielectric-property regulation of ceramic fillers, providing a composition-based material-design strategy for BaTiO 3 /polymer TENGs.