Design and Performance of ZIF-8-Based Hybrid Triboelectric Nanogenerators for Marine Energy Harvesting

Metal-organic frameworks (MOFs) have attracted considerable interest for triboelectric applications due to their high surface area, adjustable porosity, and chemical tunability without altering the crystalline framework. In this work, a hybrid-mode triboelectric nanogenerator (TENG) based on zeolitic imidazolate framework-8 (ZIF-8) was developed and characterized. The system integrates both contact-separation and sliding modes to enhance energy conversion efficiency. Structural and morphological analyses confirmed the successful formation and deposition of ZIF-8 onto the device surface. Density Functional Theory (DFT) calculations revealed a net positive surface charge on the ZIF-8 layer, supporting its favorable triboelectric performance. Polystyrene was used as the counter triboelectric layer, and the ZIF-8/polystyrene configuration achieved that under 2 Hz operation, the hybrid TENG system produced a power density of 87,3 mW/m² with a 236 MΩ load, ensuring stable energy delivery. When the load was removed (open-circuit), the power density increased to 803 mW/m², attributed to higher surface charge accumulation due to negligible current flow. These results confirm the system’s effective dual-mode energy harvesting capability. The contact mode primarily contributes to high voltage generation, while the sliding mode enables continuous current output. The TENG device was further adapted for harvesting mechanical energy from water waves by mounting it onto a floating platform, where both vertical and horizontal motions of waves drive the dual-mode system.