Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



Home > Press > Graphene may be key to leap in supercapacitor performance

Abstract:
By Dr Peter Harrop, Chairman, IDTechEx

Graphene electrodes are one of the best prospects for enabling supercapacitors and superbatteries to take up to half of the lithium-ion battery market in 15 years - amounting to tens of billions of dollars yearly. They may also be key to supercapacitors taking much of the multibillion dollar aluminium electrolytic capacitor business. That would make supercapacitors and supercabatteries (notably in the form of lithium-ion capacitors) one of the largest applications for graphene.

Graphene may be key to leap in supercapacitor performance

Cambridge, UK | Posted on August 20th, 2014

Heirarchical to exohedral?

Today's supercapacitor electrodes usually have hierarchical electrode structures with large pores progressing to small pores letting appropriate electrolyte ions into monolithic masses of carbon. In research, this is often giving way to better results from exohedral structures - where the large functional area is created by allotropes of carbon often only one atom thick. Examples are graphene, carbon nanotubes and nano-onions (spheres within spheres). Add to that the newer aerogels with uniform particles a few nanometers across.

It is not simply an area game. The exohedral structure must also be optimally matched to the electrolyte, then the pair assessed not just for specific capacitance (capacitance density) but voltage increase, because that also increases the commercially-important energy density when competing with batteries.

Nothing guaranteed

It is not a done deal. Graphene is expensive when good purity and structural integrity are required. Exohedral structures like graphene, with the greatest theoretical area, tend to improve gravimetric but not volumetric energy density. Poor volumetric energy density will cut off many applications unless structural supercapacitors prove feasible. Here the supercapacitor would replace dumb structures like car bodies, taking effectively no volume, regardless of measured volumetric energy density. Some of these formulations increase the already superb power density but that is not very exciting commercially.

Other parameters matter

Of course cost, stability, temperature performance and many other parameters must also be appropriate in all potential applications of graphene in supercapacitors and supercabatteries. Indeed for replacing electrolytic capacitors, working at 120Hz is key. In other applications, increased power density may be valuable when combined with other improvements. Nevertheless, energy density improvement is the big one for sharply increasing the addressable market - probably around 2025 or later.

Highest energy density by leveraging new generation electrolytes

Graphene gives some of the highest energy densities in the laboratory and it is particularly effective in exhibiting high specific capacitance with the new electrolytes. That means aqueous electrolytes with desirably low cost and non-flammability, and ionic electrolytes with desirably simplified manufacturing, high voltage, non-flammability, low toxicity and now exceptional temperature range.

Ionic graphene

With ionic electrolytes, graphene works despite the high viscosity that makes them ineffective in hierarchical electrode structures. On the other hand, graphene does not exhibit good specific capacitance with the old acetonitrile and propylene carbonate organic solvent electrolytes. It is advantageous that there is no solvent or solute with ionic electrolytes, though sometimes they are added to tailor the ionic supercapacitor to obtain certain performance in experiments.

Aqueous graphene

With aqueous electrolytes, graphene's accessible area is large and this offsets the low voltage to give good energy density in some experiments. Curved graphene is often used. Under a microscope it looks like crushed paper so further optimisation is possible. In the laboratory, the energy density of lead-acid and nickel cadmium batteries and even lithium-ion batteries has been achieved with various formulations involving graphene so it is likely that one of them will prove commercial in due course.

Supercabattery graphene

Recent developments by industrial companies demonstrate that graphene lithium-ion capacitor supercabattery systems can operate up to 3.7 V. They have a very good cycle life and excellent power performance.

AC graphene supercapacitors

Potentially, inverters in electric vehicles can be made smaller, lighter and have lower installed cost thanks to planned graphene supercapacitors replacing their large aluminium electrolytic capacitors. So far, it is only with vertically stacked graphene that the necessary time constant of 200 microseconds has been demonstrated suitable for such 120Hz filtering.

For more see the brand new IDTechEx report Functional Materials for Supercapacitors / Ultracapacitors / EDLC 2015-2025 and also Graphene Markets, Technologies and Opportunities 2014-2024. In addition, attend IDTechEx's events Supercapacitors LIVE! USA 2014 and Graphene & 2D Materials LIVE! USA 2014 taking place in November.

####

For more information, please click here

Contacts:

UK: +44 (0)1223 812300
US: +1 617 577 7890

Copyright © IDTechEx

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Researchers develop artificial building blocks of life March 8th, 2024

How surface roughness influences the adhesion of soft materials: Research team discovers universal mechanism that leads to adhesion hysteresis in soft materials March 8th, 2024

Two-dimensional bimetallic selenium-containing metal-organic frameworks and their calcinated derivatives as electrocatalysts for overall water splitting March 8th, 2024

Curcumin nanoemulsion is tested for treatment of intestinal inflammation: A formulation developed by Brazilian researchers proved effective in tests involving mice March 8th, 2024

Graphene/ Graphite

First human trial shows ‘wonder’ material can be developed safely: A revolutionary nanomaterial with huge potential to tackle multiple global challenges could be developed further without acute risk to human health, research suggests February 16th, 2024

NRL discovers two-dimensional waveguides February 16th, 2024

$900,000 awarded to optimize graphene energy harvesting devices: The WoodNext Foundation's commitment to U of A physicist Paul Thibado will be used to develop sensor systems compatible with six different power sources January 12th, 2024

First direct imaging of small noble gas clusters at room temperature: Novel opportunities in quantum technology and condensed matter physics opened by noble gas atoms confined between graphene layers January 12th, 2024

Announcements

What heat can tell us about battery chemistry: using the Peltier effect to study lithium-ion cells March 8th, 2024

Curcumin nanoemulsion is tested for treatment of intestinal inflammation: A formulation developed by Brazilian researchers proved effective in tests involving mice March 8th, 2024

The Access to Advanced Health Institute receives up to $12.7 million to develop novel nanoalum adjuvant formulation for better protection against tuberculosis and pandemic influenza March 8th, 2024

Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024

Battery Technology/Capacitors/Generators/Piezoelectrics/Thermoelectrics/Energy storage

What heat can tell us about battery chemistry: using the Peltier effect to study lithium-ion cells March 8th, 2024

Two-dimensional bimetallic selenium-containing metal-organic frameworks and their calcinated derivatives as electrocatalysts for overall water splitting March 8th, 2024

Discovery of new Li ion conductor unlocks new direction for sustainable batteries: University of Liverpool researchers have discovered a new solid material that rapidly conducts lithium ions February 16th, 2024

A battery’s hopping ions remember where they’ve been: Seen in atomic detail, the seemingly smooth flow of ions through a battery’s electrolyte is surprisingly complicated February 16th, 2024

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project