Graphene foam is a solid, open-cell foam made of single-layer sheets of graphene.[1][2] It is a candidate substrate for the electrode of lithium-ion batteries.

Schematic of the synthesis of graphene foam using a Ni template (top) and photographs of the products (bottom)
Electron micrographs of the graphene foam prepared using a Ni template

Synthesis

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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.[1]

Applications

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Electrode

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A physically flexible battery was created using the foam for electrodes. The anode was made by coating the foam with a lithium-titanium compound (Li
4
Ti
5
O
12
) and the cathode by coating the foam with LiFePO
4
. Both electrodes were lightweight and their large surface area provided high energy density of 110 Wh/kg, comparable to commercial batteries.[1]

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.[1]

Support

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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.[3]

See also

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References

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  1. ^ a b c d Li, Na; Chen, Zongping; Ren, Wencai; Li, Feng; Cheng, Hui-Ming (23 October 2012). "Flexible graphene-based lithium ion batteries with ultrafast charge and discharge rates". Proceedings of the National Academy of Sciences. 109 (43): 17360–17365. Bibcode:2012PNAS..10917360L. doi:10.1073/pnas.1210072109. PMC 3491507. PMID 23045691. + Supplement.
  2. ^ Timmer, John (2012). "The fast and the flexible: Graphene foam batteries charge quickly". Ars Technica.
  3. ^ Irving, Michael (2017-02-13). ""Rebar graphene" foam supports 3,000 times its own weight". newatlas.com. Retrieved 2017-02-15.

Further reading

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