Graphene foam
File:Graphene foam Ni prep.jpg
Graphene foam is a solid, open-cell foam made of single-layer sheets of graphene.{{cite journal |last1=Li |first1=Na |last2=Chen |first2=Zongping |last3=Ren |first3=Wencai |last4=Li |first4=Feng |last5=Cheng |first5=Hui-Ming |title=Flexible graphene-based lithium ion batteries with ultrafast charge and discharge rates |journal=Proceedings of the National Academy of Sciences |date=23 October 2012 |volume=109 |issue=43 |pages=17360–17365 |doi=10.1073/pnas.1210072109 |pmid=23045691 |pmc=3491507 |bibcode=2012PNAS..10917360L |doi-access=free }} + [https://www.pnas.org/content/suppl/2012/10/08/1210072109.DCSupplemental Supplement].{{Cite web |last=Timmer |first=John | url=https://arstechnica.com/science/2012/10/the-fast-and-the-flexible-graphene-foam-batteries-charge-quickly/ | title=The fast and the flexible: Graphene foam batteries charge quickly| year=2012 |website=Ars Technica}} It is a candidate substrate for the electrode of lithium-ion batteries.
Synthesis
The foam can be manufactured using vapor deposition to coat a metal foam, a three-dimensional mesh of metal filaments. The metal is then removed.
Applications
= Electrode =
A physically flexible battery was created using the foam for electrodes. The anode was made by coating the foam with a lithium-titanium compound ({{chem|Li|4|Ti|5|O|12}}) and the cathode by coating the foam with {{chem|LiFePO|4}}. Both electrodes were lightweight and their large surface area provided high energy density of 110 Wh/kg, comparable to commercial batteries.
Power density was much greater than a typical battery. At a rate that completely discharged the material in 18 seconds, power delivered was 80 percent of what it produced during an hour-long discharge. Performance remained stable through 500 charge/discharge cycles.
= Support =
In 2017 researchers used carbon nanotubes to reinforce a foam. The latter material supports 3,000 times its own weight and can return to its original shape when unweighted. Nanotubes, a powdered nickel catalyst and sugar were mixed. Dried pellets of the substance were then compressed in a steel die in the shape of a screw. The nickel was removed, leaving a screw-shaped piece of foam. The nanotubes' outer layers split and bonded with the graphene.{{Cite web|url=http://newatlas.com/graphene-reinforced-carbon-nanotube-3000-times-weight/47895|title="Rebar graphene" foam supports 3,000 times its own weight|last=Irving|first=Michael|date=2017-02-13|website=newatlas.com|access-date=2017-02-15}}
See also
References
{{Commons category|Graphene foam}}
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Further reading
- {{cite journal |last1=Paronyan |first1=Tereza M. |last2=Thapa |first2=Arjun Kumar |last3=Sherehiy |first3=Andriy |last4=Jasinski |first4=Jacek B. |last5=Jangam |first5=John Samuel Dilip |title=Incommensurate Graphene Foam as a High Capacity Lithium Intercalation Anode |journal=Scientific Reports |date=6 January 2017 |volume=7 |issue=1 |pages=39944 |doi=10.1038/srep39944 |pmid=28059110 |pmc=5216342 |bibcode=2017NatSR...739944P }}
Category:Lithium-ion batteries
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