Kinetic Characteristics of Electrochemical Reduction of SiO₂Granules in Molten CaCl₂

Abstract

The kinetic characteristics of electrochemical reduction of SiO 2 granules in molten CaCl 2 were investigated to develop a new process for producing solar-grade silicon. The reduction rate was evaluated based on the time dependence of the reduction fractions measured from the growth of the reduced Si layer and the weight change of the samples during electrolysis. The samples were prepared by potentiostatic electrolysis of SiO 2 granules in molten CaCl 2 at 1123 K. The results indicated that the reduction was fast at the initial stage of electrolysis, and gradually slowed as the reaction progressed. The apparent current density reached 0.7 A cm −2 at the initial stage, which was comparable to the commercial Hall-Héroult process for aluminum production.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.210.126.199 Downloaded on 2015-06-03 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.210.126.199 Downloaded on 2015-06-03 to IP

High purity silicon materials prepared through wet-chemical and electrochemical approaches

“…In order to evaluate potential throughput of the process, we investigated the kinetic characteristics of the reduction process [22,23]. For this purpose, we used a small electrode consisted of a graphite crucible and an alumina tube [22] because it is convenient to conduct many experiments varying parameters, e.g.…”

Electrochemical preparation of silicon nanowires from porous NiO/SiO2 blocks in molten CaCl2

“…Preparation of solar-grade silicon by the electrochemical reduction of solid SiO 2 in molten CaCl 2 has been studied for many years [11][12][13][14]. The electrochemical reduction process of SiO 2 to Si was proposed to proceed through the dynamic conductor/insulator/electrolyte three-phase interline mechanism [15].…”

The Role of Granule Size on the Kinetics of Electrochemical Reduction of SiO2 Granules in Molten CaCl2

“…Electrochemical reduction of solid oxides in molten salt has been widely studied since it was firstly reported by Fray and his colleagues. [49][50][51][52][53][54][55][56][57] We originally demonstrated that solid silica (SiO 2 ) can be electrochemically reduced to solid Si in molten salts via the solid-to-solid reaction: [58][59][60][61][62][63][64][65][66][67][68][69][70][71] SiO 2 (s) + 4e -→ Si (s) + 2O 2-(1)…”