| With the rapid development of electronic devices and electric vehicle industry,lithium-ion battery has shown broad application prospects both in the daily consumption of electronic products and in the development and promotion of new energy sources.However,the current low theoretical specific capacity(<300 m Ah g-1)of commercial lithium batteries can not meet the needs of modern high energy density energy storage devices.The theoretical specific capacity and energy density of the lithium sulfur battery with sulfur as the positive electrode and lithium metal plate as the negative electrode can reach 1675 m Ah g-1and 2600wh kg-1,respectively.In addition,sulphur is abundant on the surface,cheap and environmentally friendly.However,the practical application of lithium-sulfur batteries faces a series of problems:the poor conductivity of the charge-discharge products results in slow chemical kinetics and large polarization,and the volume expansion of sulfur during the charge-discharge process will destroy the structure of the electrodes;The“shuttle effect”of polysulfides results in rapid capacity degradation.In order to solve these problems,the continuous carbon nanotube film was applied to the flexible interlayer between the cathode and the separator of lithium-sulfur battery.In addition,the continuous carbon nanotube films and metal sulfides were used to prepare the functional interlayer which can effectively adsorb polysulfides,thus improving the cycle stability of lithium-sulfur batteries,at the same time,the electrochemical performance is also excellent under the condition of high sulfur load and current density.（1）Using ethanol as carbon source and ferrocene as catalyst,a flexible carbon nanotube film（CNTF）interlayer containing a small amount of iron was prepared by floating chemical vapor deposition method,the dense carbon nanotube network of the middle layer has good conductivity,which can make up for the deficiency of sulfur conductivity,and the middle layer also has some physical obstruction to polysulfide,the Li-S battery with CNTF interlayer has good electrochemical performance.（2）VS2was grown in situ on carbon nanotube films by continuous thioacetamide,Trisodium vanadate and Polyethylene glycol as the functional interlayer（VS2-Fe@CNT）of lithium-sulfur batteries.The mass density of the interlayer was 1.18 mg cm-2.The“rattan”network structure of the middle layer has a good barrier effect on the diffusion of polysulfide,and the chemical adsorption of the polysulfide by the vanadium disulfide on the carbon tube film can further enhance the utilization rate of the active substance,and combine with the high conductivity of carbon nanotubes,the three show a synergistic effect.The experiments of physical hindrance and chemisorption of Li2S6and in Situ Tunku Abdul Rahman test at 0.5 C confirmed that VS2@CNTF inhibited the shuttle effect.In addition,the electrochemical test results also show that the performance of the interlayer,including cycling,magnification,and Lithium anode protection,has been significantly improved,and also shows excellent electrochemical performance at high loading and high magnification. |
