Much Faster EV (& Consumer Electronic) Charging from Graphene Intentionally Engineered with Defects

August 25th, 2012 by Joshua S Hill

In an effort to solve a problem in rechargeable lithium (Li)-ion batteries that prevents them from quickly accepting or discharging energy, engineering researchers at Rensselaer Polytechnic Institute intentionally engineered defects in a sheet of graphene, resulting in a graphene anode material that can be charged or discharged 10 times faster than conventional anodes used in current li-ion batteries.

“Li-ion battery technology is magnificent, but truly hampered by its limited power density and its inability to quickly accept or discharge large amounts of energy. By using our defect-engineered graphene paper in the battery architecture, I think we can help overcome this limitation,” said Nikhail Koratkar, the John A. Clark and Edward T. Crossan Professor of Engineering at Rensselaer.

“We believe this discovery is ripe for commercialization, and can make a significant impact on the development of new batteries and electrical systems for electric automobiles and portable electronics applications.”

According to Rensselaer:

“Rechargeable Li-ion batteries are the industry standard for mobile phones, laptop and tablet computers, electric cars, and a range of other devices. While Li-ion batteries have a high energy density and can store large amounts of energy, they suffer from a low power density and are unable to quickly accept or discharge energy. This low power density is why it takes about an hour to charge your mobile phone or laptop battery, and why electric automobile engines cannot rely on batteries alone and require a supercapacitor for high-power functions such as acceleration and braking.”

Koratkar and his team made a sheet of paper from the world’s thinnest material, graphene, which is essentially a single layer of the graphite found commonly in our pencils or the charcoal burnt on barbeques, and then zapped the paper with a laser or camera flash to blemish it.

The research team believe their new battery is a critical stepping stone on the path to realising the goal of simpler, better-performing automotive engines based solely on high-energy, high-power Li-ion batteries.

The process behind the creation of the battery is explained by Rensselaer below:

“In previous studies, Li-ion batteries with graphite anodes exhibited good energy density but low power density, meaning they could not charge or discharge quickly. This slow charging and discharging was because lithium ions could only physically enter or exit the battery’s graphite anode from the edges, and slowly work their way across the length of the individual layers of graphene.

“Koratkar’s solution was to use a known technique to create a large sheet of graphene oxide paper. This paper is about the thickness of a piece of everyday printer paper, and can be made nearly any size or shape. The research team then exposed some of the graphene oxide paper to a laser, and other samples of the paper were exposed to a simple flash from a digital camera. In both instances, the heat from the laser or photoflash literally caused mini-explosions throughout the paper, as the oxygen atoms in graphene oxide were violently expelled from the structure. The aftermath of this oxygen exodus was sheets of graphene pockmarked with countless cracks, pores, voids, and other blemishes. The pressure created by the escaping oxygen also prompted the graphene paper to expand five-fold in thickness, creating large voids between the individual graphene sheets.

The researchers quickly learned this damaged graphene paper performed remarkably well as an anode for a Li-ion battery. Whereas before the lithium ions slowly traversed the full length of graphene sheets to charge or discharge, the ions now used the cracks and pores as shortcuts to move quickly into or out of the graphene—greatly increasing the battery’s overall power density. Koratkar’s team demonstrated how their experimental anode material could charge or discharge 10 times faster than conventional anodes in Li-ion batteries without incurring a significant loss in its energy density. Despite the countless microscale pores, cracks, and voids that are ubiquitous throughout the structure, the graphene paper anode is remarkably robust, and continued to perform successfully even after more than 1,000 charge/discharge cycles. The high electrical conductivity of the graphene sheets also enabled efficient electron transport in the anode, which is another necessary property for high-power applications.

“Koratkar said the process of making these new graphene paper anodes for Li-ion batteries can easily be scaled up to suit the needs of industry. The graphene paper can be made in essentially any size and shape, and the photo-thermal exposure by laser or camera flashes is an easy and inexpensive process to replicate. The researchers have filed for patent protection for their discovery. The next step for this research project is to pair the graphene anode material with a high-power cathode material to construct a full battery.”

Source: Rensselaer Polytechnic Institute

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Tags: laptops, li-ion, lithium ion, mobile phones, new battery, phones, rechargeable batteries

About the Author

Joshua S Hill I'm a Christian, a nerd, a geek, and I believe that we're pretty quickly directing planet-Earth into hell in a handbasket! I also write for Fantasy Book Review (.co.uk), and can be found writing articles for a variety of other sites. Check me out at about.me for more.

Petar Posavec

This is already old and to be honest… rather miniscule improvement.
Carbon nanotubes were patented for usage in electronics along with means of integration and production back in 1992.
Same thing happened with synthetic diamonds in 1996.

Had we used those 2 materials alone from the get go, we would have already achieved and well surpassed current technology by orders of magnitude/

Technologically speaking, Capitalism spews out minor revisions that doesn’t bring real breakthroughs because its profitable.
In the long run, Capitalism brings out the WORST of what a given material is capable of (even though they already know how to do the BEST of what it can do) and brings out the ‘new’ once every 12 to 24 months.

Graphene’s band-gap issue was solved in 2009, and was already patented for industrial scale production before then.

We are toying in technological obscurity… its’ pitiful.
http://www.facebook.com/people/Stan-Stein/1756064509 Stan Stein

Well, I certainly can’t fault anyone who makes this much of an improvement in something having a giant caveat like charge time…..no job guys!
However….batteries are no answer to automobiles…..as the population of EVs grows, so will the earth’s small supply of lithium dwindle. Additionally, the mining and mfg. of the batteries as very carbon intensive.
As a scientist, I know that my mind can be “less than optimum” for figuring out the financial aspect of situations on it’s own power, so I decided to come up with a better economic solution as a
“science project” Hahaha…..hey, and you said we don’t have senses of humor! Here’s the “formula”
Take all the costs of making and having batteries for EVs, and put it in a pile. Next, Take the pile of money, each time someone would pay into it from the higher cost of an EV over a gasoline vehicle. Let’s call it about $5000, just for the battery (we’re only talking about batteries and power here, to be fair) Now, take that $5000, and multiply it by a million vehicles….that’s…..yes…5 BILLION dollars. Now….how many people can say: “Fuel cell membrane process cost subsidy” ?????Come ON people, batteries are for small devices……automobile size models are a gross waste of a natural and limited and valuable resource…..at $5000 or so of a subsidy paid up fron by the car purchase….the cost of making fuel cell power just got affordable, and, no more batteries to dispose of, or make from limited resources.
- Bob_Wallace
  
  The Earth has plenty lithium. Lithium is not at all a problem. Don’t confuse the amount currently extracted and refined with the occurrence of lithium in the Earth’s crust. A scientist should not make that mistake.
  
  Please document your charge that battery manufacturing is very carbon intensive. As a scientist you must have had that data on hand before making that statement.
  
  Hydrogen is an inefficient way to power vehicles. As a scientist you must have cranked your way through the numbers and come to understand that.
  
  And read some economics. Learn about economy of scale and why we are currently subsidizing EVs. If that doesn’t help, then look up a materials list for EV batteries and tell us what is in batteries that is so much more expensive than what is in an ICEV engine with its fuel, cooling and exhaust systems.