Nanotube defects equal better energy and storage systems

Nov 19, 2009
Carbon nanotubes could serve as supercapacitor electrodes with enhanced charge and energy storage capacity (inset: a magnified view of a single carbon nanotube). Credit: UC San Diego

(PhysOrg.com) -- Most people would like to be able to charge their cell phones and other personal electronics quickly and not too often. A recent discovery made by UC San Diego engineers could lead to carbon nanotube-based supercapacitors that could do just this.

In recent research, published in , Prabhakar Bandaru, a professor in the UCSD Department of Mechanical and Aerospace Engineering, along with graduate student Mark Hoefer, have found that artificially introduced defects in nanotubes can aid the development of supercapacitors.

"While batteries have large , they take a long time to charge; while electrostatic capacitors can charge quickly but typically have limited capacity. However, supercapacitors/electrochemical capacitors incorporate the advantages of both," Bandaru said.

Carbon nanotubes (CNTs) have been generally hailed as one of the wonder materials of the 21st century and have been widely recognized as ushering in the revolution. They are cylindrical structures, with diameters of 1 to 100 nanometers, that have been suggested to have outstanding structural, chemical, and electrical, characteristics based on their atomically perfect structures with a large surface area-to-volume ratio. However, defects are inevitable in such a practical structure, an aspect that was first investigated by UCSD engineering graduate student Jeff Nichols and then substantially extended by Hoefer in Bandaru's lab.

"We first realized that defective CNTs could be used for when we were investigating their use as electrodes for chemical sensors," Hoefer said. "During our initial tests we noticed that we were able to create charged defects that could be used to increase CNT charge storage capabilities."

Specifically, defects on nanotubes create additional charge sites enhancing the stored charge. The researchers have also discovered methods which could increase or decrease the charge associated with the defects by bombarding the CNTs with argon or hydrogen.

"It is important to control this process carefully as too many defects can deteriorate the electrical conductivity, which is the reason for the use of CNTs in the first place. Good conductivity helps in efficient charge transport and increases the power density of these devices," Bandaru added.

"At the very outset, it is interesting that CNTs, which are nominally considered perfect, could be useful with so many incorporated defects," he added.

The researchers think that the energy density and power density obtained through their work could be practically higher than existing capacitor configurations which suffer from problems associated with poor reliability, cost, and poor electrical characteristics.

Bandaru and Hoefer hope that their research could have major implications in the area of energy storage, a pertinent topic of today. "We hope that our research will spark future interest in utilizing CNTs as electrodes in charge storage devices with greater energy and power densities," Hoefer said.

While more research still needs to be done to figure out potential applications from this discovery, the engineers suggest that this research could lead to wide variety of commercial applications, and hope that more scientists and engineers will be compelled to work in this area, Bandaru said.

Meanwhile, Hoefer said this type of research will help fuel his future engineering career.

"It is remarkable how current tools and devices are becoming increasing more efficient and yet smaller due to discoveries made at the nanoscale," he said. "My time spent investigating CNTs and their potential uses at the Jacobs School will prepare me for my career, since future research will continue the trend of miniaturization while increasing efficiency."

More information: “Determination and enhancement of the capacitance contributions in carbon nanotube based electrode systems,” Applied Physics Letters. M. Hoefer and P.R. Bandaru.

Source: University of California - San Diego (news : web)

Explore further: Researchers use oxides to flip graphene conductivity

add to favorites email to friend print save as pdf

Related Stories

Nanoscale pasta: Toward nanoscale electronics

May 18, 2007

Pasta tastes like pasta – with or without a spiral. But when you jump to the nanoscale, everything changes: carbon nanotubes and nanofibers that look like nanoscale spiral pasta have completely different ...

Customized Y-shaped carbon nanotubes can compute

Aug 15, 2005

Researchers at UCSD and Clemson University have discovered that specially synthesized carbon nanotube structures exhibit electronic properties that are improved over conventional transistors used in computers. ...

High Power Supercapacitors From Carbon Nanotubes

Feb 15, 2005

Supercapacitors that can deliver a strong surge of electrical power could be manufactured from carbon nanotubes using a technique developed by researchers at UC Davis. Supercapacitors are electrical storage devices that c ...

Nano World: Carbon nanotube capacitors

Feb 03, 2006

Carbon nanotubes could help release and hold electrical energy, for potential use in everything from microchips to hybrid cars, experts told UPI's Nano World.

Recommended for you

Researchers use oxides to flip graphene conductivity

13 hours ago

Graphene, a one-atom thick lattice of carbon atoms, is often touted as a revolutionary material that will take the place of silicon at the heart of electronics. The unmatched speed at which it can move electrons, ...

Researchers make magnetic graphene

19 hours ago

Graphene, a one-atom thick sheet of carbon atoms arranged in a hexagonal lattice, has many desirable properties. Magnetism alas is not one of them. Magnetism can be induced in graphene by doping it with magnetic ...

The latest fashion: Graphene edges can be tailor-made

Jan 23, 2015

Theoretical physicists at Rice University are living on the edge as they study the astounding properties of graphene. In a new study, they figure out how researchers can fracture graphene nanoribbons to get ...

Nanotechnology changes behavior of materials

Jan 23, 2015

One of the reasons solar cells are not used more widely is cost—the materials used to make them most efficient are expensive. Engineers are exploring ways to print solar cells from inks, but the devices ...

Gold 'nano-drills'

Jan 22, 2015

Spherical gold particles are able to 'drill' a nano-diameter tunnel in ceramic material when heated. This is an easy and attractive way to equip chips with nanopores for DNA analysis, for example. Nanotechnologists ...

The importance of building small things

Jan 22, 2015

Strong materials, such as concrete, are usually heavy, and lightweight materials, such as rubber (for latex gloves) and paper, are usually weak and susceptible to tearing and damage. Julia R. Greer, professor ...

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

dirk_bruere
not rated yet Nov 19, 2009
Numbers?
sender
not rated yet Nov 20, 2009
i think nanowool suspended in electrolytes encased in closed cells will be the future of 'air' batteries, just waiting on the statistics

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.