| Lithium ion battery, which is a sort of unpolluted and high-powered reverisble energy, is becoming more and more popular. In the first cycle of lithium ion battery, solvent decomposition reaction on the surface of electrode will lead to the formation of a passivating layer, commonly named solid electrolyte interphase film (short as SEI film), it has great impact on the electrochemical capacity, security, reversibility, self-discharge and has important significance in developing new material and improving the capability of lithium ion battery.Carbon species materials are still the dominating commercial anode materials in lithium ion battery. For these materials absorb visible light severely, the Raman signal is quite poor when measured by visible laser. Man-made diamond powder that nearly not absorbs visible light is choosed as the anode materal in this paper although it isn't practical material. And after coated with nano-silver paticle, the enhanced factor of diamond powder is lager.As a new anode material of lithium ion battery, in the discharge and recharge process, the volume of Li4Ti5O12 only change 0.1-0.3 % which is quite smaller than common carbon materials. Though the working voltage of Li4Ti5O12 is high, but the good reversibility, low price and security are prior, of which made Li4Ti5O12 the best choice in dynamical type of lithium ion battery. The enhanced factor of Li4Ti5O12 is also quite lager after coated with nano-silver paticles.In this paper Surface-enhanced Raman scattering (SERS) and related investigation techenology were adopted to in-situ study the components, adsorption-modes and evolvement course of the species of surface passivating film on anode materials—diamond powder and Li4Ti5O12. We analyzed the reaction on the surface of the electrodes and describe various evolvement processes of the species by chemical equations.We have mainly studied the contents as follows:1. We calculated the nomal Raman spectra and SERS spectra of 4-mercaptopyridine (4mpy) moleculer.Comparing the calculated assignments with experience assignments of experimental results, we get that analyzing the components of SEI film through theoretical calculated results is feasible.2. Soaked the nano-silver particles coated diamond powder in the electrolyte (EC:DMC/ 1M LiPF6) for different time, and according to the experiment results, we get that: SEI Film can create just be soaked in the electrolyte not only by electrochemistry process; the signals we measured of soaked for 180 minutes are less than soaked for 100 minutes, the reasons of this may be the enhanced factor weakened for the increasing of the thickness of SEI film. The difference of observation probability minished along with the time of soaking.3. Soaked the nano-silver particles coated diamond powder in solvent (EC: DMC), the electrolyte (EC:DMC/ 1M LiClO4 and EC:DMC/ 1M LiPF6), the species of the SEI film are different, and SEI film can create by soaking in the solvent (EC:DMC).4. The in-situ Raman spectra of SEI film were studied of Ag deposited diamond powder, and the signals were rich. On the first cycle, the SEI film on the surface of the material changed greatly, and the components were diffreent with the SEI film which were formed by soaking in the electrolyte. When the voltage declined to nearly 0.6V, the signal was strongest, and which suggested; with descending of the voltage, the signal became weaker. The Raman peaks were rich at low voltage than at high voltage, which were accorded with the SEM results.5. The in-situ Raman spectra of SEI film of Ag deposited Li4Ti5O12 powder were also studied. Combine with SEM and EIS, we analyzed the evolvement and conponents of the SEI film. On the stage of discharge and recharge, there was no signal of SEI film and the SEI film was formed at very low voltage, which was nearly 0V.
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