Single-layer hard carbons

Strueturally, the materials are grouped into two main classes, those (soft carbons) with predominantly staeked layers (CRO, KS and PVC) and those (hard earbons) which have significant amounts of single layer sheets (OXY and ENR). All the samples show similar values of L when heated to a given temperature. 

F ig. 29. Schematic graph showing the definition of the parameter, R, used to empirically estimate the fraction of single graphene layers in hard carbon samples. 

Material Shell carbon steel with 4-5 in. (10-12 cm) thick heavy weight, single-layer, cast-vibrated refractory with needles. Internals 304H stainless steel for temperature >1.200°F (650°C) and Grade H, % chrome for < ,200°F. Internal components exposed to catalyst should be refractory-lined for erosion resistance. Sliding surfaces should be hard-faced, minimum thickness in. (3 mm). 

In conclusion, a high proportion of single-layer sheets and nanopores is beneficial for the hthium storage capabilities of hard carbons. On the other hand, heat treatment, above 1000 °C, leads to drastically increased irreversible specific charges of hard carbons [249, 275]. This may be related to the bum-off of material, which causes the opening of the nanopores. Electrolyte can penetrate in, and the sites... 

MultiwaUed carbon nanotubes (MWNT) consist of a concentric arrangement of single-walled nanotubes with a usually constant distance of layers. There are examples with just two nanotubes fit one into another (sodouble-walled nanotubes, DWNTs) as well as species with many shells (more than 50). The latter measure many nanometers in diameter and may be so hard to distinguish from classical carbon fibers that only electron microscopy can reveal the difference. Common MWNTs, however, possess a smaller number of concentric tubes. The nomenclature of MWNT indicates the intercalation of the inner tubes by the notation (wi,mi) (n2,m2i (n3,m3) ...,starting from the central tube. 

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