The increasing number of functions in portable electronic devices requires more and more energy and power within a limited space. Li-ion thin film or so-called micro-batteries are the current solution for power supply. Drawbacks of these storage elements are poor power performance with limited life-span and temperature range. Carbon-based micro-supercapacitors, on the other hand, are able to deliver energy in short time, thus offering high power capability, to work at low temperature and they present an unlimited life-span. This thesis proposes several carbon-based micro-supercapacitors, to be integrated on a silicon substrate together with other electronics components or sensors. They are foreseen as a potential replacement or complement of Li-ion micro-batteries to enhance the total performance of the whole power source system. The thesis work is mainly focused on adapted materials and technologies for enabling micro-supercapacitors realization.
Two types of on-chip micro-supercapacitors with planar interdigitated electrodes configuration were developed: one prepared from electrophoretic deposition (EPD) and its combination of different carbon materials and different types of electrolytes, the other from patterned titanium or silicon carbide derived carbon film (TiC-CDC or SiC-CDC) on Si chip with different microfabrication techniques. Onion like carbon-based micro-supercapacitor by EPD shows high power delivery (scan rate up to 100V/s) in organic electrolyte, and high temperature range (-50 °C – 80 °C) in a eutectic mixture of ionic liquids. Different techniques for patterning carbide films have been developed to fabricate a CDC based micro-supercapacitor: reactive ion etching (RIE) or focused ion beam (FIB). TiC-CDC film based micro-supercapacitors show promising preliminary results. The developed technologies pave the way to a full and effective integration of micro-size energy storage devices on-chip. |