Fabrication Of P-type Amorphous Silicon Thin Films Electrode And Effect Of Gas Hydrogenation On Structure And Electrochemical Hydrogen Storage Performance

As a mature secondary battery,nickel-metal hydride batteriey（Ni-MH）has been widely popularized in many fields.However,due to the low electrochemical capacity of traditional hydrogen storage alloy anode materials and the narrow electrochemical window of aqueous electrolyte,the energy density of Ni-MH battery is lower than lithium-ion battery,which puts it in a disadvantageous position in the highly competitive secondary battery.Therefore,it is necessary to explore anode materials with high-capacity hydrogen storage and find an electrolyte solution with a wide electrochemical window for improving the market co mpetitiveness of Ni-MH battery and promoting the long-term development of nickel metal hydride industry.This paper is based on the theoretical basis that amorphous silicon has high electrochemical hydrogen storage performance,and mainly focus on the P-type amorphous silicon thin films deposited by magnetron sputtering.Firstly,the magnetron sputtering process of P-type amorphous silicon thin films has been explored.Then,the films were hydrogenated at two conditions of gas hydrogenation treatment.The influences of gas hydrogenation treatment on the surface morphology,microstructure and electrochemical performance of amorphous silicon thin films were explored by SEM,XRD,TEM,FTIR,electrochemical tests and so on,aiming to analyze the key factors that affect the performance of electrochemical hydrogen storage after gas hydrogenation behavior.The main research results are as follows:（1）The film deposition rate increases with the increase of sputtering power during the magnetron sputtering process.The introduction of sputtering bias can improve the bonding strength between the film and the substrate.But if the bias is too large,the mass of deposited substrate will be reduce d,which will cause errors in determining the mass of active material in the silicon thin film electrode.Under the conditions of a bias voltage of 50 V,a power of 300 W,and a deposition time of 3 h,the sputtering bias has a negligible effect on the loss of substrate,and the uncertainty of film mass is about 0.01 mg,which means the mass loss of film is negligible.（2）The bonding strength between silicon film and substrate can be improve d by sandblasting pretreatment.According to FTIR analysis,it is found that there are three bonding modes of Si H,Si H₂ and（Si H₂）_n in the amorphous silicon film after hydrogenation.After gas hydrogenation treatment at 300℃,5 MPa,and 500℃,1MPa,the contact angles of amorphous silicon film reduced from 50.8-51.8°to42.6-45.3°and 33.5-35.2°,respectively.（3）The electrochemical hydrogen storage performance of amorphous silicon thin film anodes in proton-type ionic liquids were explored by using a mixture of1-ethyl-3-methylimidazole acetate（[EMIM][Ac]）and glacial acetic acid as the electrolyte.The results show that the maximum discharge capacity of the non-hydrogenated P-type amorphous silicon thin film is 180.6 m Ah·g^-1 at a charge current density of 2000 m A·g^-1and a discharge current density of 200 m A·g^-1.After hydrogenation treatment at 300℃,5 MPa and 500℃,1 MPa,the maximum discharge capacity of the film increased to 316.2 m Ah·g^-1 and 1827.2 m Ah·g^-1,respectively.With the increase of the charging current density,the discharge capacity of the thin film electrode shows an increasing trend.