Temperature Difference Triboelectric Nanogenerator

In recent years,triboelectric nanogenerators(TENG)have shown great application value in fields of energy harvesting,self-powered sensing systems,and contact electrification(CE)mechanism study.Being an energy supply unit,TENG is used to harvest the widely existing mechanical energy in the ambient environment and convert it into electricity to power electronic devices such as sensors applied to various scenarios.The electrical performance of TENG is the key factor to its in-depth application.The construction of appropriate temperature difference between the two sides of the friction layers is one of the ways to enhance the electrical performance of TENG,which will facilitate the charge transfer and storage processes between the friction layers.Hence,this work focuses on the effect of temperature difference on TENG and its application.The details are as follows:1.The electron-cloud-potential-well model is adopted to analyze the charge transfer process of the friction layers of the TENG at room temperature,the ideal temperature difference and the actual temperature difference,respectively.Then,the change of surface charge density and surface potential of the friction layer caused by temperature difference is simulated by COMSOL software and calculated based on corresponding formulas.From the results of analysis and calculations,it can be seen that the charge transfer quantity,charge density and surface potential of the friction layer increase first and then decrease as the temperature difference increases,respectively.2.The temperature difference triboelectric nanogenerator(TDNG)based on Al-Kapton friction layer is fabricated,and the influence of temperature difference on its performance is studied.The results show that the electrical output of TDNG increases first and then decreases as the temperature difference continuously becomes larger.At the optimal temperature difference(?T=145 K),the output voltage,output current and charge quantity of the TDNG are respectively 858 V,20?A and 147 nC,which are 2.7,2.2 and 3.0 times that of no temperature difference.In addition,the results obtained from thermally stimulated discharge(TSD)current test,surface potential test,output test with varied contact duration of the hot and cold terminals and the repeated test of the TDNG can further prove the role of the temperature difference.3.Applications of the TDNG are conducted by adopting the effect of temperature difference on TENG:(1)The maximum output power of Al-Kapton based TDNG is206.7?W by applying appropriate temperature difference,which is 4.9 times that of no temperature difference applying,showing great improvement of the utilization efficiency of mechanical energy.(2)By constructing the temperature difference,the maximum current density can reach 396?A/cm~2 in the Al-PTFE based TDNG,which is 1.13 times that of the highest reported value(350?A/cm~2)among the contact-separation mode TENGs.(3)A demonstration of wind-driven TDNG is shown which simulates the generators on the exhaust pipe walls of automobiles,achieving the powering of a temperature and humidity sensor.