Method of and Printable Compositions for Manufacturing a Multilayer Carbon Nanotube Capacitor

Abstract

Multilayer carbon nanotube capacitors, and methods and printable compositions for manufacturing multilayer carbon nanotubes (CNTs) are disclosed. A first capacitor embodiment comprises: a first conductor; a plurality of fixed CNTs in an ionic liquid, each fixed CNT comprising a magnetic catalyst nanoparticle coupled to a carbon nanotube and further coupled to the first conductor; and a first plurality of free CNTs dispersed and moveable in the ionic liquid. Another capacitor embodiment comprises: a first conductor; a conductive nanomesh coupled to the first conductor; a first plurality of fixed CNTs in an ionic liquid and further coupled to the conductive nanomesh; and a plurality of free CNTs dispersed and moveable in the ionic liquid. Various methods of printing the CNTs and other structures, and methods of aligning and moving the CNTs using applied electric and magnetic fields, are also disclosed.

Description

FIELD OF THE INVENTIONThe present invention in general is related to energy storage technology and, in particular, is related to a multilayer carbon nanotube-based capacitor and methods of and printable compositions for manufacturing a multilayer carbon nanotube-based capacitor.BACKGROUND OF THE INVENTIONCurrent research into electrochemical supercapacitors (also referred to as ultracapacitors or electric double layer capacitors (“EDLCs”)), has revealed that these devices may be promising local energy storage devices. Other available energy storage technologies such as the Faradaic battery and conventional dielectric capacitors have drawbacks. Batteries are characterized by high energy density, low power density, and short cycle life, while dielectric capacitors are low energy density, high power density and have a long cycle life. In contrast, supercapacitors potentially may be characterized by mid-range energy storage capability, high power density and long cycle life.Three genera...

AI Technical Summary

Benefits of technology

The exemplary capacitor embodiments have a structure different from the structures of prior art capacitors, a different fabrication method, and different compositions of matter. Various exemplary capacitor embodiments have an additional layer, namely, free CNTs which are translationally and/or rotationally moveable in an ionic liquid 140. Many of the exemplary capacitor embodiments have a secondary support structure for the fixed CNTs, which provides a second support to the fixed CNTs at a second location which is separate and spaced apart from a first support location, such as the substrate. The fixed CNTs and the free CNTs are uncapped at least at one end, and have an interior diameter matched to be slightly greater than the ion size of a selected ionic liquid. The fixed CNTs have not been grown on an electrode or transferred directly from a growth plate, but have been dispersed in an ionic liquid and deposited with an i...

Problems solved by technology

Other available energy storage technologies such as the Faradaic battery and conventional dielectric capacitors have drawbacks.

Other attempts to use carbon nanotubes have included use of aligned CNTs having either a closed (capped) or an open (or uncapped) end, but have proved extraordinarily difficult to manufacture and scale up to commercial quantities.

While theoretically feasible, such alignment methods based on the growth of the CNTs are not practical beyond a laboratory environment.

Further, such complicated CNT and capacitor fabrication processes are prohibitively expensive, are not scalable and have not been able to achieve commercial production.

Such capacitor structures have not fully exploited the interior surfaces of the CNTs and the potential pore sizes of CNTs, have not addressed other methods of producing CNTs and the post-growth alignment of CNTs, and have not addressed specific energy density limitations of the resulting capacitors.

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