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

Pilot-Plant Production of High-Performance Silicon Nanowires by Molten Salt Electrolysis of Silica

“…The curved SiNWs were prepared with single silica and the straight nanowires were prepared with silica plus Ni catalysts (shown in Figure a,b). The formation mechanisms of the curved and straight SiNWs were reported in our previous papers. − , The SiNWs can also be clearly identified by TEM as shown in Figure c. A d -spacing value of 0.31 nm of the obtained SiNWs is confirmed by Figure d, which corresponds to the (111) plane of cubic Si.…”

“…However, their purities and structures of the products are usually unsatisfactory for application in LIBs. − There are few reports about the achievements in large-scale production of nano-sized silicon by the molten salt electrolysis method. According to our previous studies, − thin plates were preferred for electrolysis because of the insulativity of SiO 2 , while thick plates might result in incomplete reduction in the inner region of the SiO 2 plates and lower the electrolysis efficiency. − In this paper, we report a pilot-plant to prepare SiNWs by molten salt electrolysis for the first time. The pilot-scale electrolysis cell of the plant was successfully operated for 14 months and consistently kept in the designed working conditions.…”

“…However, this method has hardly been scaled-up because of the low solubility of SiO 2 in molten salt. It is reported that the nanowire structure could easily be controlled by reducing nanosized silica powders, especially with the addition of metal catalysts. − The nanosized silica powders can be pressed into many shapes, such as plates, rings, and granules. All these shapes are beneficial for large-scale production of SiNWs.…”

Preparation of high-purity straight silicon nanowires by molten salt electrolysis

“…In order to assist material processing, Nishimura et al developed elongated SiNWs during the electrolysis of a block of Au/SiO 2 and tetrapod-like microstructured silica powder, which indicates Au nanoparticles worked as catalysts for longitudinal nanowire growth in the electrolytic process [17] . Fang et al [30] added 8.91 wt% Ni (2.2-2.8 μm) to prepare straight SiNWs with diameter ranging from 80 to 350 nm. When prepared SiNWs were used as a negative electrode material, the obtained specific capacity was 1254 mAh/g, which is much lower than that of pure SiNWs material because of the large amount of catalyst content.…”

Continuous electrodeposition of silicon and germanium micro⁄nanowires from their oxides precursors in molten salt

“…However, continuous production of Si and Ge nanostructures still remains a challenge. In recent years, molten salt electrochemical process has been intensively developed for various micro/nanostructured materials syntheses [12][13][14][15][16][17][18][19][20][21][22][23][24][25] . In particular, molten salt electrochemical process shows promising potential for the direct synthesis of Si and Ge nanostructures from their oxides precursors [ 13-16 , 19-23 ].…”