Fully enclosed hybrid electromagnetic–triboelectric nanogenerator to scavenge vibrational energy

We propose a fully enclosed hybrid nanogenerator consisting of five electromagnetic generators (EMGs) and four triboelectric nanogenerators (TENGs). Under a vibration frequency of 15.5 Hz, one TENG can deliver a high output voltage of approximately 24 V and a low output current of approximately 24 μA, whereas one EMG can deliver a low output voltage of approximately 0.8 V and a high output current of approximately 0.5 mA. By integrating five rectified EMGs in series and four rectified TENGs in parallel, the hybrid nanogenerator can be used to charge a home-made Li-ion battery from 1 to 1.9 V in 6.3 h. By using the hybrid nanogenerator to scavenge the vibrational energy produced by human hands, a temperature–humidity sensor can be sustainably powered by the nanogenerator, which is capable of charging the 200 μF system power capacitor from 0 to 2 V in 15 s, and sustainably power the sensor in 29 s.