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Department and Staff News

2018-07-27
PolyU ME staff advance energy harvesting technology

A wind-driven hybrid triboelectric-electromagnetic nanogenerator was recently developed and tested by PolyU ME staff led by Dr Xingjian Jing. The work will be reported by Nano Energy, which is a high-impact and well-recognized journal in the area, with an impact factor 13.12 (2017 Journal Citation Report; Rank 7/146 in Applied Physics, 15/285 in Materials Sciences Multidisciplinary, 7/92 in Nanoscience & Nanotechnology).  Learn more on ELSEVIER

 

 

 Fig 1. Graphical abstract of the new invention

 

 The frequent occurrence of natural disasters is a major threat to the property and casualties of human beings in recent decades. Disaster prone points can be very closely monitored by augmenting the distribution of wireless sensor networks. However, regularly replacing the battery of electronics remains a significant challenge especially in a remote area. To this aim, a wind-driven hybridized energy harvester is invented, which can harvest rotation energy and can be integrated with WSN technology to construct a self-powered natural disaster monitoring system. In this novel harvester, the rotator is directly driven by external rotational motion thus can easily hybridize the TENNG with eighteen EMGs. Consequently, the fully packaged WH-EH device combining with the water-proof flexible solar cell can be completely isolated from the harsh wilderness environment. The output feature of TENG of high voltage but low current that perfectly compensate for the differing performance of EMG to achieve an excellent output power of the hybrid device with a broad frequency range. Moreover, the WH-EH is capable of lighting hundreds of LEDs and powering small electronics. The quick-acting charging ability of a capacitor by the WH-EH was conducted effectively in experimental tests. Three self-powered sensor systems enabled by a single WH-EH are systematically investigated and demonstrated, including a temperature sensor for forest fire detection, vibration sensor for earthquake monitoring and a wireless transceiver for alarm information spreading. Obviously, the invention of the hybridized generator will be of great importance to promote the development of self-powered wireless sensor networks and provide a sustainable power-supply solution to long-term natural disaster monitoring stations in residential or remote areas.

 

 

Fig. 2. Structural design of the WH-EH for wireless natural disaster monitoring. (a, b) Schematic illustration of the functional components of a typical WH-EH, which mainly consists of one TENG,18 EMGs and a commercial W-SC. (c) Enlarged view of the detailed structure of TENG unit. (d) An optical image of fabricated WH-EH device. The device dimension was compared with a commercial battery. (e) Schematic diagram of working principle of TENG in half cycle. Three process illustrate the charge distribution and electricity generation in short-circuit condition. (f) The cross-sectional diagrams illustrate the current direction and magnetic flux of EMG in a different moving condition.