Study On Modified Reduced Graphene Oxide As Binder For Lithium-Ion Batteries

Lithium-ion batteries are one of the most promising energy storage devices.The research and development of lithium-ion batteries with high energy,high stability,safety and long life is a hot topic at present.Reduced graphene oxide（rGO）is a functionalized graphene with the advantages of high electrical conductivity and excellent mechanical properties of graphene,and it has become a popular research material in the field of lithium-ion batteries because of its low manufacturing cost and various preparation methods.In this paper,we use L-ascorbyl palmitate（LAP）to reduce graphene oxide（GO）to obtain modified rGO（L-rGO）.Then we use it as a binder for lithium-ion batteries,and explore the properties and test the performance of the period.L-rGO has a special lamellar shape with a curled periphery,which enables a tight connection between the electrode slurry and the collector fluid and enhances the force between the slurry components.The slurry does not agglomerate and crystallize at 98%moisture content,and can be used for normal coating.The specific capacity of LTO/L-rGO half-cell at 5 C at 60°C is 155 m A·h·g^-1.The test shows that the L-rGO binder is resistant to moisture and temperature,and the lower high shear viscosity and higher low shear viscosity of the L-rGO binder slurry indicate better ductile coating.The conductivity of L-rGO binder in lithium iron phosphate（LFP）slurry is more than 1-2 times that of PVDF binder,and the slurry of L-rGO binder exhibits higher conductivity.Next,the electrochemical performance of the battery assembled with L-rGO binder was tested using LFP and lithium nickel cobalt manganate（NCM）cathode materials.The L-rGO binder has significantly improved the specific capacity and other properties of the battery,as well as the energy density and mass density of the battery,which cannot be achieved by polymer binders such as PVDF.In addition,L-rGO material can also improve the first turn Coulomb efficiency of the cell and reduce the irreversible capacity of the cell.Finally,the electrochemical performance of the cells assembled with L-rGO binder was tested using two anode materials:lithium titanate（LTO）and graphite.The Graphite/L-rGO half-cell has a specific capacity of 460 m A·h·g^-1 at 2 C with 92%Graphite mass and no degradation after 500 cycles.The CV and EIS tests show that the L-rGO binder has electrochemical stability and high conductivity.In conclusion,the L-rGO binder has excellent properties in all aspects,and the electrochemical performance of the assembled battery is significantly improved,which provides a new research direction for the application of graphene and the development and application of the binder,and the method has a broad practical application prospect.