This blog is about the storage of Lithium in varies of Carbon based structures, starting from graphite, fullerene, nanotubes, diamond and graphene. Most of the contents come from "N. A. Kaskhedikar et.al, Adv. Mater. 2009, 21, 2664-2680".
From the finding of the intercalation mechanism of Li-ion in graphite, carbon base materials has been regarded as a potential materials for electrode in batteries taking place of metallic lithium. The storage of Li-ion varies in different kind of morphology. In a Fullerene structure, lithium are stored in two different interstitial, the maximum capacity of lithium is large than 20% under this mechanism. which is illustrated below. While in a carbon nanotube, the lithium capacity is large than in the traditional graphite. However, the inner mechanism is still unknown. For the newly developed graphene, they refer to not only single layer of graphene, but also about graphite with nano scale thickness. Due to its nanostructure, graphene based materials demonstrate greater potential for lithium storage because two sides of the graphene layer used to store Li-ion.
The basic mode of lithium storage is intercalation. However, partial graphitic and disordered carbon could will provide extra space for lithium storage. In the first place, the composition of Li2C6 could be found by some graphite prepared from poly, at a distance of about 4A. Secondly, there are cavities and nanopores which could contain extra amounts of lithium. What's more, the surface and interface of materials will attract more lithium than a perfect graphitic structure. Moreover, heteroatoms will also affect the storage volume of lithium in a carbon based structure. one of the shcematic of lithium storage in disordered carbon phases has been given below:
There are a already a few models concerning the storage of lithium in different kind of defects. Details could be found in the work done by N. A. Kaskhedikar et.al as I referred in the beginning. More novel structures are under research, such as ordered mesoporous carbon, Hierarchically Porous carbon , carbon Nanotube Encapsulated Carbon Nanofibers and Superfine Expanded Graphite(s-EG)Fibers might bring a new evolution of finding stable electrode materials with higher capacity.