Preparation And Application Of Graphene

Graphene has a two-dimensional network structure in which a single layer of carbon atoms exists in a honeycomb-shaped carbon network structure.Theoretically,the graphene monolayer thickness is 0.335 nm.The superior performance of grapheme makes it possess a very broad application prospect in many fields.In order to realize the low cost,high quality preparation of graphene and explore the basic application of graphene,this paper mainly carried out the following work:（1）The graphite was intercalated with metal chloride.The first-order graphite intercalation compounds（GICs）and the second-order graphite intercalation compounds were successfully prepared.The GICs was processed by high temperature stripping and ultrasonic dispersion to obtain few-layer graphene,graphene had a higher quality by Raman analysis.The first-order GICs was stripped off better.（2）The expansible graphite was prepared by high temperature treatment to obtain worm-like expanded graphite,and the graphite sheet layer was peeled off once.The graphite flakes was obtained by grinding the expanded graphite,the size of the graphite sheet also decreased with the increasing of grinding time.In order to further peel off the graphite sheet,the sample grinded for 15 minutes was selected for subsequent experiments.,of which the size was mainly distributed around 10 microns.The graphite flakes were intercalated with anhydrous ferric chloride as intercalation agent,and the first-order GICs and second-order GICs were successfully prepared.The GICs was processed by high temperature stripping and ultrasonic dispersion to obtain few-layer graphene with high quality.The analysis showed that the first-order GICs possessed better stripping effect.Compared with stripping GICs directly,secondary stripping greatly increased the concentration of graphene dispersion.Stripping of GICs by hydrogen peroxide reaction and ultrasonic stripping of GICs by N-methylpyrrolidone were not effective and the graphite sheet was not stripped off sufficiently.However,the above two ways provide a new idea for stripping graphite sheets and have theoretical significance.（3）In this paper,a series of conductive adhesives were prepared by using silver powder and graphene as conductive fillers.The effects of fillers on the resistivity and thermal conductivity of conductive adhesives were investigated.The results showed that the resistivity of the conductive adhesive decreased with the increasing of the mass fraction of silver powder.When the mass fraction of silver powder was 80%,the resistivity of the conductive adhesive was the lowest,approximately 6.12×10^-4Ω·cm.The thermal conductivity of the conductive adhesive increased firstly and then decreaseed with the increasing of the mass fraction of silver powder.When the mass fraction of silver powder was 75%,the thermal conductivity of the conductive adhesive was the highest,approximately 1.854 W/m·K.When the mass fraction of silver powder was 80%,the resistivity of conductive adhesive decreased firstly and then increased with the increasing of graphene content.When the graphene content was 0.02%,the resistivity of conductive adhesive was the lowest,approximately 3.35×10^-4Ω·cm,which reduced resistivity by45%compared to conductive adhesive not doped with graphene.The thermal conductivity of the conductive adhesive increased with the increasing of graphene content.When the graphene content was 0.04%,the thermal conductivity of the conductive adhesive was the highest,approximately 1.744 W/m·K,up to 127%higher than conductive adhesive not doped with graphene.After the addition of graphene prepared by different preparation methods,the electrical resistivity and thermal conductivity of the conductive adhesive were different.