PhD - Leuven | More than two weeks ago
Develop integrated printed thin-film micro-supercapacitors to assist the energy management of autonomous multi-sensor platforms based on flexible hybrid electronics for the internet of things.
Sensing/actuating nodes at the edge of internet of things (IoT) are crucial in connecting physical objects to the digital platform across a wide range of application domains such as transportation/logistics, environment, industrial, health, etc. Energy management of these IoT nodes is a great challenge since they may need to be battery-less due to cost and use-case constraints, or because battery replacement may not be a viable option due to cost and logistics overhead for such large amount of distributed systems. Moreover, batteries utilize materials and processes that are altogether not always compatible with the low-cost production of the IoT sensing nodes. For this reason, it is desirable to use power-autonomous systems capable of harvesting their own energy from their surroundings, without any need for battery recharging or replacement. The Thin Film Electronics group at IMEC is developing flexible hybrid (thin-film/Si chips) electronics based sensors platform that requires energy harvesting to eliminate the need of batteries. However, energy harvesting (wireless electromagnetic energy, photovoltaic, etc.) is not always sufficient to power the large number of sensors and electronics required for such IoT sensing platforms. Moreover, harvested energy may suffer from supply interruptions too. To address these issues, we propose in this research a tight collaboration between the Thin Film Electronics group at IMEC and the Department of Materials Engineering at KU Leuven in the development of an autonomous multi-sensor platform with an integrated micro-supercapacitor and related components that can assist its power and energy management.
Supercapacitors are energy storage devices typically composed of two large-area electrodes and an electrolyte in between. The electrolyte possesses mobile ions that move towards the interface of the electrodes generating a high charge-storage situation: an electrical double layer (EDL), a redox reaction, atoms intercalation, etc. Supercapacitors lie in between batteries and standard dielectric capacitors: they can store few times more energy than standard capacitors, but charge and discharge faster than batteries (on the other hand, they store less energy than batteries and charge/discharge slower than capacitors). Therefore, the electrical properties of supercapacitors are suitable to fill the gaps of energy harvesting, since these devices can quickly store any excess of available energy, and deliver it to the system during the energy shortages.
The PhD candidate will evaluate different electrolyte materials for supercapacitors and study the charge storage working principle. Moreover, he/she will investigate multi-scale nanostructuring strategies that combines nanopatterning and the use of nanomaterials, to increase the electrode surface area to enhance further the capacitance value. Because the supercapacitor needs to meet the requirements for operation and integration in the sensing platform, we will take a holistic approach from the beginning to guide the selection of materials, device design and processes. For instance, only materials and processes compatible with the already-established fabrication of the sensing platforms can be used, the device should have a thin film structure, its cost must be viable, and its electrical specifications (input/output voltage and charging/discharging time) must meet the requirements of the sensing platform. Those requirements will be derived based on one or two selected applications. To tackle these limitations, we propose the use of nanoimprint lithography (NIL) and printing methods. On one hand, NIL allows nanopatterning on flexible substrates. On the other hand, additive and non-contact printing techniques like inkjet or dispensing allow the simultaneous deposition and patterning of a myriad of materials on the same substrate that the rest of the system, but with minimal disturbance to the components already present in the system. The digital character of those techniques permits also quick prototyping by adapting the layout of the device to the needs of the system. Throughout the project, the candidate will first fabricate and test a standalone micro-supercapacitor that meets the mentioned compatibility requirement. Then, the fabrication steps of the device will be included in the process flow of the sensing platform fabrication. Finally, the operation of the whole system will be tested. The success of this project will pave the way towards truly autonomous and performing smart systems with increased sensing functionalities for the IoT.
Required background: Engineering Science with specialization in Material Science, Physics, Electronics or Equivalent.
Type of work: 20% Design, 70% Experimental, 10% Literature
Supervisor: Jan Genoe
Daily advisor: Cedric Rolin
The reference code for this position is 2021-106. Mention this reference code on your application form.