| Lithium metal has the advantages of high theoretical specific capacity(3860 m Ah g-1),low density(0.534 g cm-3)and extremely low reduction potential（-3.040 V）,which make it recognized as one of the most suitable anode materials in the world since this century.However,Lithium metal anode is easy to form Lithium dendrites,which will lead to low columbic efficiency,poor stability and reversibility.In order to inhibit the formation of Lithium dendrite,in this paper,we use carbon nanotube（CNT）and graphene to construct three-dimensional conductive structures,and prepare carbon nanotube/graphene macro films（CNT@Gr GO）with high conductivity and low defects by adjusting the degree of reduction then introduce it into the Lithium metal anode as a high conductivity and low defect intercalation layer.By improving the ion diffusion rate and electron transmission rate,uniform Lithium deposition/stripping can be achieved,so that the Lithium metal anode can maintain high columbic efficiency and high capacity retention in application.（1）By regulating the concentration of graphene oxide（GO）solution and the mass ratio of CNT to GO,a three-dimensional conductive platform is built,which can not only effectively control the interlayer spacing of graphene composite films and prevent graphene lamellar agglomeration,but also increase a large number of active contact sites in the longitudinal direction,improve the high electron mobility of graphene films confined to the plane,and improve the longitudinal and overall conductivity.（2）By adjusting the reduction degree of graphene composite film,the oxygen-containing functional groups of CNT@GO are removed and the lattice defects are repaired,which make the crystal plane structure of graphene more complete and the degree of graphitization higher.Through the Raman and FTIR tests of graphene composite films with different reduction degrees,it is found that the lower the number of functional groups retained on graphene composite films and the higher the C/O ratio,the higher the conductivity and electromagnetic shielding properties of graphene composite films.In graphitized CNT@Gr GO,more C=C bonds are formed,so the tensile strength of the composite film is also improved.（3）Li/CNT@Gr GO shows excellent stability in the battery,the characteristic of electrophilic electrolyte of CNT@Gr GO can make the electrolyte quickly infiltrate the battery components,and the diffusion speed of ions in the battery will be faster,so it also shows lower ion transfer impedance and electron transfer impedance.At the same time,the high conductivity and low diffusion barrier of CNT@Gr GO make the nucleation barrier of Lithium on the anode surface significantly lower than that of Bare Li,which is conducive to the diffusion of Li+between active substances on anode surface,the highly graphitized and low defect structure is also beneficial for Lithium to evenly plate/strip,so that Li/CNT@Gr GO can maintain a low hysteresis voltage（～20 m V）throughout the long cycle,and even changing the current density will not affect the stable cycle of the battery,showing excellent multiplier performance.During130 cycles,the average coulombic efficiency is 99.7%. |
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