Hosted by IDTechEx
Printed Electronics World
Posted on April 2, 2009 by Dr Peter Harrop

Nanotecture develops asymmetric electrochemical supercapacitors

IDTechEx recently visited Nanotecture, a 2003 spinoff from Southampton University in the UK that is located at Southampton Science Park. It has raised £7-10 million so far and it is well placed to ride out the recession. Its business model is to both license and manufacture.
Nanotecture develops asymmetric electrochemical supercapacitors not to be confused with the traditional electrolytic capacitor which also has an electrolyte and has to be connected the right way around (it is "polar"). AEDLCs have many names because that term does not exactly trip off the tongue and they perform in a manner that is intermediate between supercapacitors that are symmetric electrochemical double layer capacitors EDLCs, and batteries.
Supercapacitors are otherwise known as ultracapacitors and they were first commercialised as recently as 1978 by NEC in Japan. Nanotecture has something even smaller than symmetric supercapacitors it has higher energy density (energy per unit of volume or mass eg 16-18 mWh/cm3). So far, so confusing but the uses could include those where rechargeable batteries and supercapacitors are used today such as energy harvesting.
Register that supercapacitors pack one thousand times more capacitance even than electrolytic capacitors because their insulating layer is only nanometers thick. This is because it is formed within and electrolyte, not by electrochemically growing a dielectric compound as with electrolytic capacitors or extruding a ceramic or plastic film as with an electrostatic capacitor. There is no dielectric. Assymetric versions of the supercapacitor take half of its symmetric structure and build something like half a battery on the other side.
See the picture below for a comparison of an electrostatic capacitor, an electrolytic capacitor and an EDLC.
Source: NREL
See below for a comparison of an EDLC with an asymmetric supercapacitor sometimes painfully called a bacitor or supercabattery.
Source: ELIT
Nanotecture calls its small paper thin versions for electronics microbatteries - a generic term with a high value perception that is used for many small batteries. It calls its large versions supercapacitors.
The small devices will be aimed at markets such as boosting the flash in mobile phone cameras to take pictures farther away, audio buffering in mobile phones etc for higher quality sound and powered smart cards. It seems to us that they could be made at high speed reel to reel in due course and they will be useful in disposable e-labels, e-packaging, medical testers and drug delivery systems such as electronic skin patches.
After all, we are talking of something potentially much thinner than a smart card - indeed paper thin, though it needs protection and cells are built on top of each other to gain higher voltage or energy storage.
The large Nanotecture devices can tackle energy harvesting, perhaps taking on Maxwell Technologies with its $30 million business in supercapacitors for wind turbines or those serving the electric vehicle market with supercapacitors. The supercapacitor business may be a few hundred million dollars yearly.
The small Nanotecture devices can be coin shaped but much thinner and the cleverest part is nanoporous nickel hydroxide on one electrode. Activated carbon is on the other electrode as in a conventional supercapacitor . A big plus is the electrolyte being water based and therefore more environmental. This is potentially a printed or partially printed device in the opinion of IDTechEx and sampling will take place in a few months as the remaining challenges of durability and miniaturisation are solved.
Technical Manager Dr Phil Nelson told us that he expects his device to replace many supercapacitors on size and price. The company does not see it replacing batteries.
IDTechEx can see how this may indeed happen and it will be put in places where there is no room for a supercapacitor but there is currently a limitation with it withstanding no more than thousands of recharges - like a battery - rather than millions like a supercapacitor and being polar.
Will it have the life of a conventional supercapacitor? Either way, we feel that there is a huge market for very small load balancing devices like these for energy harvesting in wireless sensor nodes and many other applications where small electric and electronic equipment needs to be made self-sufficient. For more see External Link.
Learn more at the next leading event on the topic: Business and Technology Insight Forums - Tokyo, September 2019 External Link on 18 - 19 Sep 2019 at Tokyo, Japan hosted by IDTechEx.

Authored By: Dr Peter Harrop


Posted on: April 2, 2009

More IDTechEx Journals