| Lithium-ion batteries have been widely used in various fields,such as portable electronic devices,new energy vehicles and energy storage power stations.The negative electrode is one of the important components of the battery,and its performance directly affects the energy density and power density of the battery.Compared with traditional graphite anode materials,graphene materials have many advantages,such as high specific surface area,excellent electrical conductivity,chemical and electrochemical stability,etc.In addition,its morphology,surface chemical state,layer number and size have certain tunability,so it is a good cathode material.However,two-dimensional（2D）graphene is prone to stacking,which reduces its specific surface area and fails to give full play to its el ectrochemical properties.Modification of two-dimensional graphene morphology and self-assembly of crimped graphene can give full play to the advantages of graphene electrode materials.In this paper,a large temperature difference between liquid nitrogen and GO solution was used to prepare crimp GO by freezing it instantaneously to crimp it.Crimp reduced GO was obtained after reduction at high temperature.The influences of the concentration of GO dispersion(0.4 mg·m L-1,0.5 mg·m L-1,1 mg·m L-1 and 2 mg·m L-1),the adding style of the dispersion（dropping in,pouring in and putting in）and the te mperature of the dispersion（20℃,50℃ and 80℃）on GO crimp were studied.The results of SEM and TEM showed that go was transformed from a two-dimensional sheet to a vinami-line,and a three-dimensional network structure was formed by crossing each other.XRD characterization results showed that the material image structure did not change significantly,indicating that the instantaneous freezing did not have a great impact on the phase structure although it changed the morphology.Raman spectrum showed that the surface of 0.5 mg·m L-1 go dispersion had the most active sites.The electrochemical properties of crimp reduced GO obtained under different preparation conditions were tested.Compared with two-dimensional（2D）flake graphene,the cyclic stability and multiplier properties of crimp graphene were improved.0.4 mg·m L-1,0.5mg·m L-1,1 mg·m L-1 and 2 mg·m L-1 concentrations of crimped reduced GO were prepared.After circulating for 1000 cycles at the current density of 10000 m A·g-1,the specific discharge capacity was 187 m Ah·g-1,404 m Ah·g-1,313 m Ah·g-1 and 121 m Ah·g-1respectively.The crimped reduced GO was prepared by dropping,pouring,and putting in three ways.After circulating for 1000 cycles at the current density of 10000 m A·g-1,the specific discharge capacity was 187 m Ah·g-1,157 m Ah·g-1,and 421 m Ah·g-1 respectively.The crimped reduced GO was prepared by 20℃,50℃,80℃ three temperature.After circulating for 1000 cycles at the current density of 10000 m A·g-1,the specific discharge capacity was 187 m Ah·g-1,86 m Ah·g-1,94 m Ah·g-1.According to the comprehensive comparison and analysis,the crimp r GO prepared by dropping liquid nitrogen with 0.5mg·m L-1 GO dispersion solution（at 20℃）has good electrochemical performance and is simple to make.The r GO prepared under these conditions presents linear and sp herical mixed morphology.0.5 mg·m L-1 GO dispersion（at 20℃）was dropped into liquid nitrogen to prepare curly r GO.The morphology of the curly r GO increased the effective adsorption of lithium ions,expanded the lithium storage capacity,and the increased space also enhanced the lithium storage capacity.The special morphology also avoided the stacking and agglomeration of graphene sheets,which made its excellent physical and chemical properties prominent. |
