Ultra-robust and broadband rotary hybridized nanogenerator for self-sustained smart-farming applications

Highlights: • Miniaturized hybridized (electromagnetic-triboelectric) nanogenerator for effectively harvesting rotational energy. • Soft magnetic-coupled triggering strategy for ultra-robust triboelectric nanogenerators. • High output performance under a broad range of rotational motions (50-1000 rpm). • Implementing nanofiber-based tribo-layers increase the charge density by 5.7 times. • Successful demonstration of a self-powered wireless smart-farm monitoring system. The practical realization of nanogenerators for realistic applications of scavenging sustainable energy is still challenging due to their limited output performance and mechanical durability. Herein, a contactless mode triggering-based ultra-robust rotary hybridized nanogenerator (CMTUr-HNG) for efficiently harvesting wind- and water-flows in natural environments is reported. By implementing a soft magnetic-coupled triggering strategy, the hybrid electromagnetic-triboelectric nanogenerator shows high output performance under a broad range of rotational motions (50–1000 rpm) with excellent robustness. The electrospun nanofibers materials greatly improve the triboelectric performance while the electromagnetic structure is optimized by finite element method simulations. Therefore, the as-fabricated CMTUr-HNG delivers a maximum hybrid power of 40.65 mW at a matching load resistance, while triboelectric and electromagnetic generators show a high output power density of 1568 mW/kg and 386 mW/kg at 500 rpm, respectively. The robustness of CMTUr-HNG is confirmed by a durability test for 8.5 h (≈2,000,000 cycles) at 1000 rpm. As a feasible application, a self-powered wireless smart-farm monitoring system has been successfully implemented using the CMTUr-HNG, thereby demonstrating the immense potential of harvesting rotational energy for future autonomous sensing technologies.