High-resolution on-chip supercapacitors with ultra-high scan rate ability
Résumé
A simple approach for the fabrication of high-resolution on-chip supercapacitors with increased performances is demonstrated. The resulting micro-devices display high specific cell capacitance (3 mF cm-2 using hydrous ruthenium oxide electrode) and impressive scan rate abilities, up to 10 000 V s-1 for multi-walled carbon nanotubes based micro-supercapacitors, which is five orders of magnitude higher than conventional supercapacitors. The tremendous push towards systems on chip (SoC) approach together with the decrease of their dimensions has enabled the development of new applications such as wireless sensors network or wearable devices that can be integrated into everyday-use objects. As microelectronic devices get smaller and smaller, it has become critical to power them with micro-power sources of appropriate size, fulfilling specific requirements for self-powered applications such as long lifetime and high-rate charge/discharge capabilities. Electrochemical capacitors (also called supercapacitors) show very interesting characteristics when it comes to these applications, because of their extended lifetimes and high power densities. Supercapacitors store electrical energy using the electrochemical double layer formed at the electrode/electrolyte interface (electrochemical double layer capacitance) or the very fast and reversible electrochemical reaction of some materials deposited at the surface of an electrode (pseudocapacitance).
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