Si@C/TiO₂@C/Hollow-C Nanocomposite as a Lithium-Ion Battery Anode Produced by Refining Silicon and Ti–6Al–4V Residuals

Abstract

TC4 (Ti–6Al–4V) nanoparticles (TC4NPs) and silicon nanoparticles (SiNPs) with a median size of 146 and 51 nm were prepared by sand milling from scrap produced by refining silicon and TC4. The SiNPs and TC4NPs are mixed, carbonized, and leached in different proportions to obtain Si@C/TiO2@C/Hollow-C anode materials. The special structure of the anode materials provided more space for the volume expansion of silicon. The anatase TiO2 in TC4NPs relieves the volume expansion and reduces the transfer impedance, and the lithiated TiO2 can promote the electrical conductivity of the Si@C/TiO2@C/Hollow-C anode during the charge/discharge process. Furthermore, the Si@C/TiO2@C/Hollow-C (SiNPs/TC4NPs = 2:1) electrode delivers excellent rate performance; after cycling at a series of higher current densities, 92% of the original level of the reversible capacity can be maintained. The Si@C/TiO2@C/Hollow-C (SiNPs/TC4NPs = 2:1) anode retains 558 mA h·g–1 after 400 cycles with a large current density of 1000 mA·g–1. The synthesis method of the Si@C/TiO2@C/Hollow-C anode is a low-cost, facile, and nontoxic process, endowing it with the potential for application as energy materials for mass production.

Synthetic Strategy of Si@void@C Nanoparticles for High-Performance Lithium-Ion Battery Anodes

“…Pore size distribution of Si@void@C is concentrated at 0–5 nm. Abundant pore structures and high specific surface area of material are conducive to the transmission of Li + and also alleviate the volume change of silicon. − …”

Three-Dimensional Porous Si@SiOx/Ag/CN Anode Derived from Deposition Silicon Waste toward High-Performance Li-Ion Batteries

“…15,17 The above issues bring about the crack and disintegration of the electrode and the formation of an unstable solid electrolyte interface (SEI), resulting in rapid attenuation of specific capacity. 18,19 In the last few years, many scientific researchers were committed to solving the inherent bottleneck of silicon anodes to successfully apply silicon waste to high-performance lithiumion batteries. The relevant studies have shown that grinding silicon waste to the nanoscale can availably enhance the cycle stability of electrodes.…”

“…Silicon is deemed to be the most prospective anode material for lithium-ion batteries and has attracted widespread attention. Nevertheless, the practical application of silicon anodes is greatly hindered by the huge volume expansion during insertion/extraction of lithium ions (300%) and the poor intrinsic electronic conductivity (4 × 10 –4 S cm –1 ). , The above issues bring about the crack and disintegration of the electrode and the formation of an unstable solid electrolyte interface (SEI), resulting in rapid attenuation of specific capacity. , …”