In Situ Formation of Nickel Nanoparticles from Nickel Formate for Preparation of Straight Silicon Nanowires by Molten Salt Electrolysis

摘要

Water-soluble nickel formate(Ni(HCOO)2),which can be dispersed uniformly in silica(SiO2),was used as the catalyst precursor for producing silicon nanowires(SiNWs)by molten salt electrolysis in this work.Ni(HCOO)2/SiO2 pellets were decomposed into Ni/SiO2 and NiO/SiO2 pellets in N2 and air atmosphere,respectively.The NiO particles could retain the initial size in molten salt due to their high melting point,while the Ni particles were always aggregated.Thus the NiO particles possessed a larger catalytic surface area than the Ni particles.After long time electrolysis of NiO/SiO2 pellets in a pilot-plant,the obtained silicon presented a smooth and straight nanowire morphology and offered a delithiation capacity of 1995.5 mAh/g after 100 cycles when used as negative electrode material.These findings may have an important significance in mass production of straight SiNWs for lithium ion batteries.