UC Irvine

Carbon-MicroElectroMechanical systems (C-MEMS) use patterning and nanofabrication techniques developed for integrated circuits (ICs) in combination with traditional carbon pyrolysis to create intricate 3-D carbon materials and electrodes from organic precursors. The fabrication of specialized, pyrolytic carbon microfeatures and geometries, such as carbon micro-post arrays or interdigitated electrode arrays (IDEAs), significantly enhances carbon’s electrical, chemical and mechanical properties to create high performance sensors and energy storage devices.

However, C-MEMS is generally limited to using amorphous or glassy carbons since most inexpensive carbon microfabrication processes require cross-linking a non-graphitizing polymer precursor. The inability to change the microstructure of a polymer precursor to a configuration that yields graphitic carbon inhibits the performance of the resulting material. Furthermore, traditional processes for functionalizing carbon using surface modifications are typically too harsh for its small microfeatures. The ideal solution is to develop a fabrication process that allows for the structural and surface modification of pyrolytic carbons without sacrificing cost or scalability. The results of this work present a novel method for electromechanically modifying the microstructure and surface properties of carbon to significantly enhance its electrochemical activity. Specifically, the results of a comprehensive materials and electrochemical characterization of the structurally modified carbon reveals a new class of stress-activated pyrolytic carbon (SAPC). The SAPC showed a remarkable improvement in graphitization and demonstrated an inherently high and enduring electrocatalysis that has yet to be seen with any other pyrolytic carbon to date. Furthermore, the SAPCs simple and scalable synthesis process is compatible with common C-MEMS fabrication processes, creating a new tool for C-MEMS operators to tune the properties of their carbon electrodes.