A Research On Electrochemical Reduction Of Tetrachlorosilane With Cyclic Voltammetry And Feature Of Polysilicon

Because of the global energy shortage, solar energy which is more and more global attention regard as a sustainable development. The world's photovoltaic industry is in a period of vigorous development. As the demand for polymer silicon and organic silicon output increased year by year, by-product silicon tetrachloride gives prominence to safety environmental problem. Untreated recovery silicon tetrachloride is a kind of toxic or corrosive liquids. Large backlog of silicon tetrachloride by-product has affected the economic efficiency of enterprises and has seriously polluted the environment.The electrochemical reduction of silicon tetrachloride can carry through at room temperature and under atmospheric pressure. Ti-Nb-Ni and nickel were used as working electrode, graphite was used as the reference electrode, saturated calomel was used as reference electrode, propylene carbonate was used as solvent, Tetrabutylammonium chloride was added to the electrolyte solution as a supporting electrolyte, silicon was successfully electrodeposited potentiostatic.Cyclic voltammetry of Ni (Φ18mm) base is in 30ml PC solution (0.5mol/LSiCl4 +0.1 mol / L TBACl), scanning potential range is -5v ~ 5v, scanning speed is 20mv / s, peak potential is -2.627v; scanning speed is 2mv / s, peak potential is -2.17.The faster scan rate is, the more negative peak potential shifts to.Scan speed is 50mv / s, scan potential range is -4v ~ 4v. Cyclic voltammetry of Ni (Φ18mm) base is in 30ml PC solution (0.6mol/LSiCl4 +0.1 mol / L TBACl), the peak potential is -2.569v, peak current density is -5.283mA/cm~2; Cyclic voltammetry of Ni (Φ18mm) base is in 30ml PC solution (0.8mol/LSiCl4 +0.4 mol / L TBACl), the peak potential is -2.568v, peak current density is -15.205mA/cm~2. The larger solute concentration is, the larger peak current density is. Cyclic voltammetry of Nickel niobium titanium alloy (40:30:30, wt%;Φ10mm) is in 15mlPC solution (including 5gTBACl) +20 mlSiCl4.Scanning speed is 20mv/s, peak current density is -6.600mA/cm~2; scanning speed 50mv/s, current density is -6.807mA/cm~2. When the solution is constant, the peak current is proportional to the square root of that scanning speed.As the longer electrodeposition time, the deeper deposition of silicon film thickness. Nickel was used as working electrode. It was possible to electrochemical reduction of silicon chloride at -2.5V. Time of electrodeposition is 4h,2h,1h respectively, the silicon film thickness is 0.4μm, 0.1μm, less than 0.1μm respectively. Ti-Nb-Ni was used as working electrode. It was possible to electrochemical reduction of silicon chloride at -2.398V. Time of electrodeposition is 4h,2h respectively, the silicon film thickness is 2.4μm, 0.5μm.