Low‐Cost Synthesis of Porous Silicon via Ferrite‐Assisted Chemical Etching and Their Application as Si‐Based Anodes for Li‐Ion Batteries

Abstract

orientation of Si nanostructures relative to the substrate, and the high surface-to-volume ratio structures, and all the experiments can be carried out in a chemical lab without expensive equipment. [ 28 ] However, because of the use of noble metal as the catalysts, the fabrication cost is still too high for practical applications. Recently, Jiang et al. developed a simple and inexpensive method to prepare porous Si powder by acid etching Al-Si alloy powder. [ 29 ] Qian's group reported a hydrothermal synthesis of porous Si anode materials using very cheap silica sol. [ 30 ] Our group developed a scalable method for synthesis of porous Si materials by using the Rochow reaction commonly used in the organosilane industry, in which the Si microparticles react with gas CH 3 Cl over Cu-based catalyst, and demonstrated their promising application as porous Si/C anode materials in Li-ion batteries (LIBs). [ 20 ] In recent years, there has been an increasing demand for portable electronics, electric vehicles, and energy storage devices/technologies, which has stimulated signifi cant interest in LIBs with both high energy density and power performance. [ 31,32 ] Comparing with graphite (372 mAh g −1 ), Si is considered to be the next generation anode materials for LIBs, because of its large theoretical capacity (4200 mAh g −1 ), relatively low discharge potential (≈0.5 V versus Li/Li + ), abundant resource, low cost, and safety. [ 33 ] Tremendous efforts have been made to synthesize Si-based anodes with porous structure and coated with a conductive carbon layer to improve the capacity and cycling performance, [ 34,35 ] include porous Si particles, [ 36,37 ] and porous Si/C composites. [ 38 ] This is because the porous Si structure can absorb the huge volume change of Si during Li insertion and extraction reactions and hinder the cracking or crumbling of the electrode, whereas the porous Si/C composites can possess the advantages of both C (long cycle life) and porous Si. [ 39 ] In addition, carbon coated porous metal oxides composites are also good anode materials for LIBs because of their larger lithium storage capacities and better safety than that of the commercially used graphite. [ 40,41 ] Inspired by above mentioned reported work about noble metal-assisted chemical etching method, [ 24,25 ] here, we developed another novel method to prepare porous Si materials using the low-cost ferrite catalyst by replacing the noble metals to catalyze the reaction between Si and liquid glycol. This new approach inherits the advantages of the noble metal-assisted chemical etching method but avoids its disadvantages and can be easily scaled up for porous Si materials production. Compared with recent other low cost synthesis porous Si strategies (such as acid etching Al-Si alloy powder [ 29 ] and hydrothermal synthesis using silica sol, [ 30 ] this strategy has advantages of Nanostructured porous Si materials have received great attention because of their numerous potential applications in electronics, [1][2][3] photonics, [4][5][6] ...

A Green and Facile Way to Prepare Granadilla‐Like Silicon‐Based Anode Materials for Li‐Ion Batteries

“…[ 12 ] Silicon nanoparticles (Si NPs) have been found to tolerate extreme changes in volume with cycling. [ 13 ] Hence, great efforts have been made to improve the cycling stability and electrical conductivity by using various Si-based nanostructures, including Si nanowires, [ 3,14,15 ] porous Si, [16][17][18][19] and conductive agent coated Si such as carbon, [ 18,20,21 ] Ag, [ 22,23 ] and conducting polymer. [ 24 ] Among them, a yolkshell-structured carbon@void@silicon (CVS) composite [ 25,26 ] is quite promising for practical applications, because the void space between the outer carbon shell and the inside Si NP allows the room for volume changes of Si NP without deforming the carbon shell and SEI fi lm, which in turn allows for the growth of a stable SEI on the surface of the outer carbon shell.…”

Glucose hydrothermal encapsulation of carbonized silicone polyester to prepare anode materials for lithium batteries with improved cycle stability

“…The necessity of introducing graphene has been verified, because the generation of holes is conducive to the lithiation and delithiation, so that it has better electrical performance. 45 The hydrothermally treated SiO x /C-rGO-2 is shown in Fig. 3d and e .…”

When Silicon Materials Meet Natural Sources: Opportunities and Challenges for Low‐Cost Lithium Storage

“…Such structure effectively alleviate volume expansion, that gives rise to the high reversible capacity and long cycle life. [ 102 ] Nanostructured Si has great benefits as LIBs anode material in enhancing both the capacity and cycle life. Metal‐assisted chemical etching is applied to produce multidimensional Si electrodes from the commercially available Si.…”