Placing supercapacitors in a chip

In-chip PS–TiN supercapacitor. (a) representation of the of the trenches separating the electrodes. (b) Schematic illustration of the cross-section of two opposite electrodes of a ready device (TiN coated PS layer and the aluminium contact pads on the back side are also present). (c) Higher magnification SEM picture of the porous regions. Credit: Kestutis Grigoras et al./Nano Energy

Supercapacitors are usually bulky devices that can store significant amount of energy, like a capacitor but with higher capacity... somewhere between 10 to 100 times more than a capacitor (but less than a chemical battery).

This capacity would turn out handy for powering chips (that require much less power than an electric car...) but the bulkiness of supercapacitors makes this impossible. Till now.

Researchers at VTT, Finland, one of the EIT Digital Core Partners, have developed a technology that can create micro-supercapacitors, so tiny that can actually fit onto a chip.

The crucial component is a nano-electrode, just a few nano-metre thick. It is made of porous silicon covered with titanium nitride. This solution provides a high (the highest so far) surface to volume conductivity, that makes possible to obtain hight power throughput even within the tiny dimension of a chip.

Tests show a one square cm of this supercapacitor can deliver 55 microwatts of power for one hour. Additionally, the design is such that on the same surface it is possible to place the electronic circuit for the sensor and microchip.

This result can find important application in the wearable domain where powering of chip is still one of the major hurdle to overcome.

Author - Roberto Saracco

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