Ohta R, Gerile N, Kaga M, Kambara M
Department of Materials Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo 113-8656, Japan.
Nanotechnology. 2021 Apr 7;32(26). doi: 10.1088/1361-6528/abef2b.
Si-Ni composite nanoparticles have been produced by a single and continuous plasma spray physical vapor deposition (PS-PVD) from Si and Ni powder feedstocks and their electrochemical performances as anode in lithium-ion batteries (LiB) are investigated. Si nanoparticles with 20-40 nm on which Ni is directly attached with Si/NiSiepitaxial interface are formed spontaneously through co-condensation of high temperature elemental gas mixtures during PS-PVD. When only a little amount of Ni is added to Si, the effect of the epitaxial Ni attachment on the Si nanoparticles becomes evident; the cycle capacity is appreciably improved to reach a 1.6 times higher capacity than that of the Si only cell after 50 cycles, due to reduced charge-transfer resistance and nanosized Si particle. In contrast, excessive Ni addition to Si feedstock leads to formation of various silicides as a result of the accelerated silicidation during PS-PVD, which results in a significant decrease in the cycle capacity due to reduction of the active Si phase amount despite reduced charge-transfer resistance.
通过单步连续等离子体喷雾物理气相沉积（PS-PVD）法，以硅粉和镍粉为原料制备了硅-镍复合纳米颗粒，并研究了其作为锂离子电池（LiB）负极的电化学性能。在PS-PVD过程中，通过高温元素气体混合物的共冷凝，自发形成了直径为20-40nm的硅纳米颗粒，镍直接附着在硅颗粒上，形成了Si/NiSi外延界面。当仅向硅中添加少量镍时，镍在外延硅纳米颗粒上的附着效果变得明显；由于电荷转移电阻降低和硅纳米颗粒尺寸减小，50次循环后，循环容量显著提高，比仅含硅的电池高出1.6倍。相比之下，向硅原料中过量添加镍会导致在PS-PVD过程中硅化加速，形成各种硅化物，尽管电荷转移电阻降低，但由于活性硅相含量减少，循环容量显著下降。
