A recyclable and green triboelectronic nanogenerator (TENG) is developed based on triboelectrification and designed cascade reactions. Once triggered by water, the TENG can fully dissolve and degrade into environmentally benign end products. With features of rapid dissolution, reproductivity, and green electronic, the TENG has potential of serving as clearable energy harvester and nanosensor for health monitoring and motion sensing.

Nowadays, mankind faces increasingly energy crisis and electromagnetic radiation pollution. An energy harvester with function of protecting human health from electromagnetic radiation is a desirable solution to this problem. Here, a stretchable electromagnetic shielding hybrid nanogenerator (ES-HNG) is reported which can not only scavenge thermal and mechanical energy from living environment but also protect and monitor human health. The ES-HNG is capable of transforming mechanical and thermal energy to electricity based on triboelectric, piezoelectric, and pyroelectric effects. To be devised as a computer keyboard cover, ES-HNG takes about 200 s to charge a capacitor to 3 V by typing. The stored energy can drive the portable devices successfully. Besides, the ES-HNG eliminates electromagnetic radiation of computer completely due to its unique electromagnetic shielding property. A large range of electromagnetic wave (frequency is between 0 and 1.5 GHz) is shielded more than 99.9978% by the ES-HNG. Moreover, the ES-HNG is able to monitor human health by attaching it on human abdomen to be a self-powered sensor. This work opens up a new prospect of harvesting energy effectively as well as protecting/monitoring human health from electromagnetic radiation surroundings. as human motions, which plays an important role with respect to wearable electronics. [3][4][5][6][7][8][9] However, the power output from the TENG is not enough to actuate most of wearable electronics. Therefore, hybrid nanogenerators (HNGs) which integrate TENGs with other nanogenerators were developed to solve the problem of low output. The developed HNGs can simultaneously/individually scavenge the mechanical and thermal energy from the living environment efficiently. [10][11][12][13][14] As a crucial candidate to a part of HNG, pyroelectric-piezoelectric nanogenerator (PPENG) which based on poly(vinylidene fluoride) (PVDF) scavenges thermal energy with a temperature gradient and mechanical energy from environment efficiently. [15][16][17] Occasionally, the HNG serves as a self-powered monitor by utilizing the triboelectric, piezoelectric, and pyroelectric effects. [18][19][20] However, the simple stacking of the PPENG with the TENG seriously restricted application of HNG. On the other hand, electromagnetic radiation has become a serious pollution issue which threatens human health. [21,22] Epidemiological surveys have proved that excessive amounts of electromagnetic radiation can cause extensive biological damage effects especially for the pregnant women. [23][24][25] However, most conventional antielectromagnetic radiation equipments are cumbersome and cannot function well in the GHz range. A good solution for the problem is developing electronics which are wearable and portable to be antielectromagnetic. Above all, a new type wearable and portable HNG is much desired, which includes wide electromagnetic shielding range. DOIHere in this work, we developed a stretchable, portable, and wearable electromagnetic shielding HNG (ES-HNG) which composed...

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Raindrop falling, which is one kind of water motions, contains large amount of mechanical energy. However, harvesting energy from the falling raindrop to drive electronics continuously is not commonly investigated. Therefore, a self-cleaning/charging power system (SPS) is reported, which can be exploited to convert and store energy from falling raindrop directly for providing a stable and durable output. The SPS consists of a hydraulic triboelectric nanogenerator (H-TENG) and several embedded fiber supercapacitors. The surface of H-TENG is amphiphobic, enabling the SPS self-cleaning. The fiber supercapacitor which uses α-Fe 2 O 3 /reduced graphene oxide composite possesses remarkable specific capacitance, excellent electrical stability, and high flexibility. These properties of the fiber supercapacitor make it suitable for a wearable power system. A power raincoat based on the SPS is demonstrated as application. After showering by water flow, which simulates falling raindrops, for 100 s, the power raincoat achieves an open-circuit voltage of 4 V and lights a light-emitting diode for more than 300 s. With features of low cost, easy installation, and good flexibility, the SPS harvesting energy from the falling raindrop renders as a promising sustainable power source for wearable and portable electronics.

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