Hybrid Spring-Coupled Broadband Energy Harvester Integrated with CuSCN Functionalized Triboelectric Vibration Sensor for Self-Sustainable Vehicular IoTs.

Energy harvesting from low-acceleration, broadband vehicular vibrations remains challenging due to low-amplitude and random frequency nature of such excitations, often poorly matched to conventional narrowband spring-mass designs. Herein, a hybrid spring-coupled broadband vehicle vibration energy harvesting(VEH) and triboelectric vibration sensing(TVS) module is proposed that exploits coupled mechanical resonance and frequency disparity between spring elements to achieve vibration amplification under low-amplitude and wide-frequency excitations. VEH combines the motion dynamics of high stiffness 3D printed multiturn wave spring and low-stiffness metallic disc spring, enabling simultaneous vibration of coil and magnet for enhanced mechanoelectrical conversion over braoder frequency (1-30 Hz). Simulations and experiments confirmed that the dual-spring coupling yields superior mechanoelectrical conversion (above 50%) under 0.5 g with peak and average powers of 260 mW(5.72 mW/cm3) and 88 mW(1.89 mW/cm3). Furthermore, lightweight spiral spring-integration with PAN-CuSCN composite nanofiber provides self-powered vibration sensing through its pronounced tribonegative response as compared to the pristine nanofiber, enabling accurate road classification(>95%) and speed classification (84.1%) with minimum detection upto 0.075g. This dual-functional module combining broadband energy harvesting, self-powered vibration sensing with miniaturized PCB, integrated sensors and BLE allows continuous operation in realistic vehicular vibration environments, establishing a reliable framework for self-sustainable vehicular environmental monitoring systems.