Effect of the substrate material on kinetics and mechanism of silicon electrodeposition from the KCl–KF–K2SiF6 melt

S. I. Zhuk, T. A. Gevel, Yu. P. Zaikov. 

ABSTRACT

    In this work, the influence of the substrate material on the kinetics and mechanism of silicon electrodeposition from the (mol %) 66.51KF-33.26KCl-0.23K₂SiF₆ melt at a temperature of 750°C was studied by means of cyclic chronovoltammetry. It was shown that silicon electrodeposition on glassy carbon, silver, and silicon electrodes occurs in the potential region from -0.05 to -0.20 V relative to the potential of the silicon quasi-reference electrode. Silicon electrodeposition is accompanied with the cathode current peak formation. Based on the analysis of the i_p(ν^1/2) and E_p(lnν) dependences, it was found that the process under study is proceeds in one electrochemically irreversible step. On the nickel electrode, silicon electrodeposition occurs at a potential more negative than 0.20 V relative to the potential of the silicon quasi-reference electrode. Such depolarization associated with the formation of the Ni₂Si compound.

     According to the Matsuda-Ayabe equation for an electrochemically irreversible process, the diffusion coefficients of electroactive ions was estimated, which ranged from 2.8 to 5.8·10^-5 cm²/s, depending on the material of the cathode substrate.

    On the basis of electrochemical measurements, the parameters of silicon electrodeposition on different cathode substrates were determined.

KEY WORDS:

silicon, KCl-KF-K₂SiF₆, electrodeposition, chrono voltammetry, alloying

DOI: 10.31857/S0235010621040101