Deborah Number-Governed Surface Roughness Control of Sulfur-Rich Polymer Film via Micro-Scale Surface Tearing for High-Performance Triboelectric Nanogenerator
Surface engineering is vital for high-performance triboelectric nanogenerators (TENGs), as triboelectrification is a surface-dominant mechanism. While structuring the surface enhances charge induction, conventional micro/nano-patterning is often complex and costly. In this study, we report a mechanically governed, one-step surface engineering strategy using sustainable sulfur-rich polymers derived from elemental sulfur. By employing a low-surface-energy polyimide (PI) superstrate during hot-pressing, we facilitate localized stress accumulation at the interface. During peel-off, this stress induces spontaneous surface roughening, eliminating the need for lithographic steps. Results show that tuning the peel speed from 0.1 to 800 mm s⁻¹ increases surface roughness from 0.84 to 3.35 μm. This led to a 224% enhancement in peak voltage (441.1 V) and a 13.7-fold increase in power density, reaching 532.3 mW m⁻² at 100 M Ω. Furthermore, the high-performance TENG directly illuminated 153 blue LEDs, demonstrating a scalable and efficient route for high-output energy harvesting from waste-derived materials.