*Article* **Natural Rubber-TiO2 Nanocomposite Film for Triboelectric Nanogenerator Application**

**Weeraya Bunriw 1, Viyada Harnchana 2,3,\* , Chalathorn Chanthad <sup>4</sup> and Van Ngoc Huynh <sup>5</sup>**

	- 2800 Kongens Lyngby, Denmark; vannh@dtu.dk

**Abstract:** In this research, natural rubber (NR)-TiO2 nanocomposites were developed for triboelectric nanogenerator (TENG) application to harvest mechanical energy into electrical energy. Rutile TiO2 nanoparticles were used as fillers in NR material to improve dielectric properties so as to enhance the energy conversion performance of the NR composite TENG. The effect of filler concentration on TENG performance of the NR-TiO2 composites was investigated. In addition, ball-milling method was employed to reduce the agglomeration of TiO2 nanoparticles in order to improve their dispersion in the NR film. It was found that the TENG performance was significantly enhanced due to the increased dielectric constant of the NR-TiO2 composite films fabricated from the ball-milled TiO2. The TENG, fabricated from the NR-TiO2 composite using 24 h ball-milled TiO2 at 0.5%wt, delivered the highest power density of 237 mW/m2, which was almost four times higher than that of pristine NR TENG. Furthermore, the applications of the fabricated NR-TiO2 TENG as a power source to operate portable electronics devices were also demonstrated.

**Keywords:** natural rubber; triboelectric nanogenerator; TiO2 nanoparticles; dielectric constant
