清华大学材料科学与工程研究院《材料科学论坛》

学术报告

报告题目：Advanced Thermal Energy Harvesting ?Devices for Low-Power Electronic Applications

报告人：Prof. Dongyan Xu（Department of ?Mechanical and Automation Engineering, The Chinese University of Hong Kong）

报告时间：2019年5月23日（周四） 上午10:00

报告地点：清华大学逸夫技术科学楼A205学术报告厅

联系人：李亮亮老师 62797162

欢迎广大师生踊跃参加！

Abstract
With the recent advance of ?wireless sensor network and wearable electronics, there is a strong ?motivation to develop low-cost energy harvesting devices that can ?scavenge energy from the ambient environment and convert it to ?electricity. In this talk, I will present our recent research efforts ?on developing two types of thermal energy harvesting devices: (1) ?thermoelectric generators; (2) thermogalvanic cells. High power ?density micro-thermoelectric generators were developed by integrating ?pulsed electroplating with microfabrication processes. Through ?systematic optimization of materials properties, a record high power ?density of 20.0 mW cm-2 is achieved at a temperature difference of ?36?C for flexible thermoelectric generators. The high power density ?can be attributed to enhanced thermoelectric properties of ?electroplated materials, low parasitic contact electrical resistance, ?and high packing density of thermoelectric pillars. Compared to ?traditional thermoelectric materials, redox couples could achieve a ?much larger Seebeck coefficient typically on the order of mV/K. ?Recently, we demonstrated that I-/I3- redox couple could be tuned from ?“p-type” to “n-type” by adding thermoresponsive polymer into the ?electrolyte. The Seebeck coefficient and p-n conversion temperature ?were further tuned by adding potassium chloride solutions with ?different concentrations. At optimal conditions, we are able to ?achieve Seebeck coefficients of 6.0 mV/K (p-type) and -8.06 mV/K ?(n-type) for I-/I3- redox couple, in sharp contrast to 0.8 mV/K for ?pure I-/I3- electrolyte.

Biography
Prof. Dongyan Xu is ?currently an Associate Professor in the Department of Mechanical and ?Automation Engineering, The Chinese University of Hong Kong (CUHK). ?Prof. Xu received her Bachelor, Master, and Ph.D. degrees from ?Tsinghua University and Vanderbilt University. After that, she worked ?as a Postdoc in the University of California, Berkeley and Lawrence ?Berkeley National Laboratory for two years. She joined CUHK in 2010 as ?an Assistant Professor and was promoted to Associate Professor in ?2016. Her current research interests include nanoscale heat transfer, ?thermoelectric materials and devices, thermal management, and boiling ?heat transfer.