High-performance triboelectric nanogenerator based on sulfur-rich polymer/MXene composites for value-addition of waste sulfur

Triboelectric nanogenerators (TENG) have garnered attention as green energy harvesters, converting wasted mechanical energy into useful electricity. State-of-the-art TENGs typically have utilized fluoropolymers for outstanding TENG output performance. However, the controversy around fluoropolymers is rapidly growing because of their high probability of releasing hazardous small molecular perfluoroalkyl substances (PFAS) throughout their life cycle which are commonly used as processing aids for fluoropolymers. In this presentation, we developed a sulfur-rich polymer (SRP)/MXene composite with a segregated structure, offering a PFAS-free, reusable, and high-performance TENG. SRP with sulfur as backbone is a promising material for high-performance yet sustainable TENG, thanks to the fact that sulfur is abundant waste from petroleum refining and possesses high electron affinity (−200 kJ mol⁻¹). To enhance the potential of SRP-based TENG, we utilized less than 0.5 wt% of MXene as a filler, which exhibited both high electrical conductivity and negative surface charge density. Additionally, we introduced a segregated structure to achieve a homogeneous distribution of MXene inside SRP. The segregated structure induces a significantly enhanced dielectric constant of SRP without a drastic increase of dielectric loss, resulting in 2.9-fold and 19.5-fold enhancement in peak voltage and peak current of SRP/MXene composites-based TENG compared to previous SRP-based TENGs. Also, SRP/MXene composites were thermally reprocessed and reused multiple times without reduction in either TENG output performance or modulus due to dynamically exchangeable sulfide bonds in SRP. Finally, after corona discharging and scaled-up processing to a 4-inch size, SRP/MXene-based TENG exhibited a record-high peak power density of 3.80 W m⁻², representing an 8.4-fold improvement compared to previous SRP-based TENGs.