On-Chip Integrated Electrochemical Energy Storage Devices Based on Photopatternable Solid Electrolytes
The rapid proliferation of wireless sensor networks in the era of the Internet of Things provides a unique opportunity for the next wave of technological innovations, ranging from wearable biosensors in the healthcare sector to cloud computing. However, conventional tools available to power these networks and miniaturized electronics are severely limited due to the stringent size constraints. Three fundamental research objectives addressing this challenge are the development of advanced electrode material systems, device designs that significantly improve power and energy density of traditional thin-film microbatteries and the demonstration of solid electrolytes, which can facilitate miniaturization and integration without the inherent risk of leakage. The research of this dissertation is directed towards the latter effort by creating microscale, on-chip solid electrolyte systems capable of being integrated at the point of load. A key feature here is to develop photopatternable solid electrolytes that can be processed directly on electrodes.In this dissertation, novel photopatternable electrolyte materials and processing methods are introduced and characterized. A basis for the material development is to chemically modify SU-8 negative photoresist without compromising its photopatterning functionality. The synthesized photopatternable solid electrolytes demonstrate excellent mechanical integrity and electrochemical properties with the ability to be integrated in lithium-ion batteries, electric double-layer capacitors, and pseudocapacitive energy storage systems. The outcome of this research is to extend the miniaturized batteries and supercapacitors into the important direction of high-energy and high-power solid-state electrochemical energy storage devices.