The high cycling performance of ultra-thin Si nanowires fabricated by metal-assisted chemical etching method as lithium-ion batteries anode

Abstract

Abstract The main method for the fabrication of Si nanowires (SiNWs) includes chemical vapor deposition (CVD) and metal-assisted chemical etching (MCE). In the conventional MCE method, Ag catalysts are generated in a Ag+ solution. Because of the anisotropic growth of crystalline Ag, the size of the SiNWs is limited. To etch thinner SiNWs, compact and porous catalysts have been fabricated by fast-ion sputtering on Si substrates. Then, ultra-thin SiNWs (approximately 10 nm) can be etched by HF and H2O2 solution. The SiNWs fabricated by the two different methods above are assembled in a CR2025 coin cell. The 2nd discharge capacity of ultra-thin SiNWs and conventional SiNWs is 2483 and 2187 mAh/g, respectively. After 100 cycles, the discharge capacity is 1823 and 1156 mAh/g, that means the conventional SiNWs decays about 47% and ultra-thin SiNWs decays about 27%. It shows that the ultra-thin SiNWs exhibit higher cycling performance and electrochemical activity.