why graphene is more conductive than graphite

Question

anonymous · Answer

First, welcome to OpenStudy :-) Second, there's a number of factors as to why... Primarily, graphene is artificially prepared, and thus has a higher purity than most graphite (or rather graphite commonly has impurities). Often times these impurities are intentional in order to make graphite harder (for pencil leads, the lower H#, the more pure it is, the higher the H# the more clay is added in to maker it harder; i.e. HB2 is your standard pencil lead). These impurities do decrease conductivity, notably. Then if you really want to get into the quantum-level details of why, you'll need to understand electron orbitals and wave numbers and start by taking a look at this: http://en.wikipedia.org/wiki/Anomalous_quantum_Hall_effect#Pseudo-relativistic_theory

chmvijay · Answer

simple answer is graphene is one layer as result flow of electrons is in only one direction where as that of graphite is lots of layers flow of electrons will have some indifference during the flow

anonymous · Answer

@chmvijay that's not quite correct, sorry...  Multi-layer graphene does exist, it has been produced, and it exhibits very similar properties to graphite electrically except that it's working with a resonance structure (giving it electron flow velocity properties close to what you'd see in metallic lattice bonding) instead of just being suspended 0.335 nm apart.   The reason why has to do with wave number in how each of the planar "crystal" plates are constructed.

Again the driving factor here is purity, followed by how the layers are stacking together.

chmvijay · Answer

along with that vector direction of electron play important role in this

anonymous · Answer

Purity, that's all.  By definition graphene is a single extended network, while graphite consists of many stacks of flakes of graphene crammed together higgledy-piggledy.  Lattice defects reduce the delocalization length of quasielectrons -- meaning, electrons traveling in the conduction band can go less distance before they crash into something, roughly.