Posted on 04/30/2013 11:41:25 AM PDT by neverdem
A graphene inspired electrode material that could help batteries hold more power has been developed by Chinese scientists. The large surface area of these cobalt oxide nanosheets is key to their electrochemical performance.
Batteries are a cornerstone of modern life with most smartphones and laptops using rechargeable lithium ion batteries. As technology advances, the search is on for batteries that can pack more energy into the same space.
Graphitic electrodes are commonly used in lithium ion batteries but suffer from low theoretical capacity. A viable alternative is to use metal oxides which have significantly higher theoretical capacities but in practice are limited by their inability to hold more lithium ions. Recently nanostructures have been developed that can hold more lithium ions but the swelling and shrinking from charge–discharge cycles damages the electrode and greatly reduces its capacity, a problem known as pulverisation.
Yi Xie and her team from the University of Science and Technology of China, Hefei, have bypassed these issues using an inorganic analogue of graphene. They fabricated atom-thick sheets of cobalt oxide via a topochemical method. Xie says the structure of the analogue allows for ‘huge surface areas, facile lithium ion diffusion and electron transport, as well as open channels that buffer large volume variation during cycling processes’. All of these factors contribute to its significant electrochemical performance and high cyclability in comparison with previous Co3O4 nanostructures.
‘Exploiting nearly the full outstanding capacity of conversion anodes for lithium batteries at good capacity retention has been a longstanding goal for which this work offers an interesting approach,’ comments Stefan Freunberger, an expert in electrochemical energy storage materials at Graz University of Technology, Austria. However, he warns that translating such performance into a device remains a tough challenge.
Xie also says that the technology is still in the early stages of development. Next, she plans to experiment with other inorganic graphene analogues using other materials to achieve even better energy storage properties.
J Zhu et al, Nanoscale, 2013, DOI: 10.1039/c3nr01178j
I tried an inorganic nanosheet but my wife said it made her legs itch. So we went back to cotton.
Watch out for that stuff ~ even your CFLs are doing element transmutation and it’s just a question of time and somebody’s going to interleave a bunch of graphene nanosheets with a bunch of electroconductive porous metals (just full of proton holes) and blow up the neighborhood!
The neatest applications for these new high energy density materials is for bombs.
When you start the storing of any form of potential energy with an energy density on par with fossil fuels or greater, they can burn or explode- just like those other forms of energy.
And they can be more unstable.
Just ask Boeing about their Lithium Ion Batteries on 787.
I don’t know. Thanks for the link. I’ll check it later.
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FReepmail me if you want on or off my health and science ping list. Anyone can post any unposted link as they see fit. That last link, while some cool chemistry, looks like chat bait.
That link was about the recharging time. This one is about electrode durability.
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