Abstract:

A non-faradaic junction can form between an ionic conductor and an electronic conductor in the absence of electrochemical reaction. The junction couples ions and electrons through chemistry, electricity, and entropy, and functions like a capacitor. Its voltage-charge curve is sensitive to various environmental signals (e.g., pressure, sound, temperature, and chemicals), so that the junction can be used as a sensor. Here, we illustrate the principle of non-faradaic junction sensing using temperature sensing and chemical sensing. The sensor is self-powered because the junction capacitor is pre-charged. The sensor is sensitive because the junction capacitance is large, ~0.1 F/m2. The sensor is rapid because the junction thickness is small, ~1-10 m-9. The sensor is stable because no electrochemical reaction takes place. The flexibility in choosing ionic and electronic conductors enables non-faradaic junction sensors to meet unusual requirements, such as softness, transparency, stretchability, and degradability, for emerging applications. We demonstrate applications of non-faradaic junction sensors in stretchable electronics and soft robots. Non-faradaic junction can be a platform for ubiquitous sensing to connect everyone and everything in new and useful ways.

Biography:

Yecheng Wang is an associate professor at Sun Yat-sen University. He earned his B.S. degree in Applied Physics from Xi’an Jiaotong University, M.S. degree in Engineering Mechanics from Tsinghua University, and Ph.D. degree in Engineering Sciences from Harvard University. Afterwards, he worked as a Postdoctoral Fellow at Harvard University. He is a recipient of the NSFC Excellent Young Scientists Fund. His research centers on solid mechanics, soft materials, and stretchable ionotronics.

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