Interface Study Of Silicon Anode Materials For Lithium Ion Batteries And Raman Spectra

Lithium-ion batteries have been widely applied to power up portable electronics,hybrid electric vehicles and even electric vehicles due to their high energy density,economic feasibility,less self-discharge and relative environmental friendliness.The traditional anode graphite is the industry standard in manufacturing.However,its theoretical capacity(372 mAh g-1)is relatively low,more attention has been devoted to the silicon anode material(4200 mAh g-1).Unfortunately,silicon anodes suffer from comparatively lower specific capacity due to the large volume difference of the charge and discharge states of the silicon electrodes.In our research,we have been focused on binder modification and coating silane outside silicon particles to improve the interface structure,and we studied the interface characteristics and the electrochemical performances.In addition,the Raman spectra were investigated to indicate the molecular behavior.The Raman spectra of solids in various matrices were obtained using a universal substrate we developed,having a laminate film containing silver nano-particles.It is expected to fulfill its promising application potential and be mass produced.This thesis mainly includes the following contents(1)The cross-linked network were formed via an esterification reaction mixing sodium alginate and polyacrylic acid.The three dimensional network can buffer the volume variation in the charge-discharge and influence the interface reaction.Consequently,it can form a thinner solid electrolyte interphase and obtain a stable interface.(2)Nano-silicon was modified by hydrolysis of silane on the surface,then calcined in nitrogen to form silica oxide on the surface of silicon.The silica oxide on the surface of silicon was the soft layer to stabilize the interface and exhibited better specific capacity.(3)The silver film was obtained by transferring silver nano-particles into the silicone rubber.Then it was used to detect the molecules on the surface.The data indicate the silver nanoparticles in the film can generate the surface enhanced Raman phenomenon.Therefore the fabricated silver films can be applied to detect the solid substance and research the behavior of the molecules on the surface.