Synthesis Of Graphene-based Materials And Studies On Electrochemical Properties

In recent years,with the development of the electric equipments,especially the emergence of new energy vehicles,it requires higher energy density and power density of lithium ion batteries.Besides,anode material is one of the decisive factors for improving the performance of lithium ion batteries.The traditional commercial anode material is graphite with unfortunately low Li intercalation capacity(372mAh g^-1 ideally)and poor rate capability,which hinders the improvement of ion battery electrochemistry performance,so developing anode materials with high performance is the key factor to promote the rapid development of lithium ion batteries to electric equipments.Graphene,a new carbon material,has attracted intensive research interests for energy-related applications due to its atomically thin 2D geometrical structure,prominent intrinsic physical and chemical features.In this paper,the grapheme-based porous materials is used as the research object and the graphene-based multihole anode materials with high performance are designed and prepared to improve the electrochemical properties of lithium ion batteries.Graphene-based nitrogen doped porous carbon?GNC?was prepared by Template-free,in the preparation process,sodium citrate is used as carbon source,urea is used as nitrogen source.The research results show that the GNC has well electrochemical performance and large specific surface area(743.5 m² g^-1)by heat treatment temperature of 700?;The conductivity and electrochemical activity of GNC were improved by nitrogen doping,which promoted the rate capability and cycle performance of GNC.The honeycomb graphene-based porous carbon anode material was prepared by hard-template.It is found that iron nitrate nonahydrate is beneficial to the formation of suitable pore structure that can provide high specific surface areas and more active sites and is advantageous to the lithium ion storage of HGPC,so as to improve the rate capability and cycle performance of HGPC.An initial discharge specific capacity of3184.8 mAh g^-1 was achieved at a current density of 100 mA g^-1,and after 250 cycles,the reversible specific capacity was 724 mAh g^-1 at a current density of 1000 mA g^-1,meanwhile the coulomb efficiency was close to 100%.