利用Y₂O₃稳定的ZrO₂固体电解质(YSZ)管集成构建Pt, O₂(air)|YSZ作为参比、辅助电极的三电极新型电化学池,在完全无碳和1323 K条件下采用Ir丝作工作电极对Na₃AlF₆-5%SiO₂ (质量分数)熔盐体系进行循环伏安(CV)及恒电位电解测试,并结合热力学理论计算、SEM观察及EDS分析,研究了熔盐中有关金属在阴极上的析出电位及电沉积规律。结果表明,Si单质在Ir电极上可一步沉积得到,其在CV曲线上的峰电位在-1.65 V,而Al、Na (Zr)等合金化沉积电位负于-1.8 V,且沉积电位依次负向增大。在-1.8 V或-2.0 V电位下电解,还发现有Zr₅Si₄金属化合物颗粒生成,其生成电位在-1.7~-1.8 V之间。沉积的Si、Al、Na金属(合金)主要来源于Na₃AlF₆-SiO₂熔盐本身产生的含氧化合物,而沉积的Zr源于Na₃AlF₆基熔盐对YSZ管的侵蚀产生的ZrO₂。有关金属(或金属化合物)相对于Pt, O₂(air)|YSZ参比电极的析出电位与热力学计算较为吻合。

Electrodeposition of silicon from a cryolite-based melt is a possible solution for the mass production of silicon with high purity. Currently, deposition of Si from dissolved SiO₂ in cryolite-based melts occurs primarily in a graphite crucible using graphite and quasi-reference electrodes, resulting in series of problems, such as CO _x emissions due to carbon participation, non-significant peak positions on cyclic voltammetry (CV) curves due to melt electronic conduction, various reference standards of metal deposition potential, and insufficient investigations on electrode reaction mechanism due to melt composition complexity. In this work, a novel three-electrode electrochemical cell with Pt, O₂(air)|YSZ reference (RE), and counter electrodes (CE) was constructed using a Y₂O₃ stabilized ZrO₂ solid electrolyte (YSZ) tube, CV and potentiostat electrolysis tests were performed on Ir wire working electrode in Na₃AlF₆-5%SiO₂ (mass fraction) melt under the conditions of a complete carbon-free and 1323 K. The precipitation potentials of related metals on the cathode in the melt were investigated, and the electrodeposition law in the melt at different potentials was analyzed, using a combination of thermodynamic theoretical calculations, SEM observation, and EDS analysis. The results show that Si can be deposited on the Ir wire in a single step, and its peak potential is about -1.65 V on the CV curve, while the deposition potentials of Al, Na (Zr) are all negative than -1.8 V and increase negatively in turn. During potentiostatic electrolysis, intermetallic compound particles of Zr₅Si₄ are observed to generate at -1.8 V or -2.0 V, with a generation potential of -1.7 V to -1.8 V. The deposited Si, Al, and Na metals are mainly derived from oxygen-containing compounds produced by the Na₃AlF₆-SiO₂ melt itself but Zr metal from the ZrO₂ of the corrosion of YSZ tubes by the melt. The precipitation potentials of related metals (or intermetallic compounds) relative to Pt, O₂(air)∣YSZ RE agree well with thermodynamic calculations.