Electrochemically anodized porous silicon: Towards simple and affordable anode material for Li-ion batteries

Abstract

Silicon is being increasingly studied as the next-generation anode material for Li-ion batteries because of its ten times higher gravimetric capacity compared with the widely-used graphite. While nanoparticles and other nanostructured silicon materials often exhibit good cyclability, their volumetric capacity tends to be worse or similar than that of graphite. Furthermore, these materials are commonly complicated and expensive to produce. An effortless way to produce nanostructured silicon is electrochemical anodization. However, there is no systematic study how various material properties affect its performance in LIBs. In the present study, the effects of particle size, surface passivation and boron doping degree were evaluated for the mesoporous silicon with relatively low porosity of 50%. This porosity value was estimated to be the lowest value for the silicon material that still can accommodate the substantial volume change during the charge/discharge cycling. The optimal particle size was between 10–20 µm, the carbide layer enhanced the rate capability by improving the lithiation kinetics, and higher levels of boron doping were beneficial for obtaining higher specific capacity at lower rates. Comparison of pristine and cycled electrodes revealed the loss of electrical contact and electrolyte decay to be the major contributors to the capacity decay.

Conjugation with carbon nanotubes improves the performance of mesoporous silicon as Li-ion battery anode

“…preparation and modification of pSi particles and cnts. PSi microparticles were prepared in a similar fashion as reported previously 16 and their pore size distribution was confirmed with gas adsorption (Micromeritics Tristar II 3020). The particles were sieved between 10 µm and 25 µm sieves (Precision Eforming) and their size was confirmed with laser diffraction (Malvern Mastersizer 2000 with Hydro 2000S accessory).…”

“…Some studies have managed to successfully employ micrometer sized silicon with reasonable mass loadings 13,14 . Another viable option is to utilize mesoporous silicon (PSi) material that can accommodate most of the volumetric changes and make the anode more robust 15,16 .…”

Scalable 2D Mesoporous Silicon Nanosheets for High‐Performance Lithium‐Ion Battery Anode

“…An alternative and effective approach to enhance electrochemical performance of Si anode is to construct mesoporous structure with high specific surface area, which can effectively accommodate the volume expansion and buffer the structural stress during repeated cycling . In addition, this mesoporous architecture provides large electrode–electrolyte interface, accelerating the electrolyte permeation and promoting the transport of lithium ions.…”

Nanostructured Silicon as Potential Anode Material for Li-Ion Batteries

“…The first is combining Si with different kinds of carbon materials such as amorphous carbon [25][26][27], conductive carbon black [28], carbon nanotubes [29,30], and graphene [31][32][33], and the second is by designing nanoscale silicon with different structures. Currently, extensive research has been carried out to develop nanostructures of silicon i.e., silicon nanoparticles [27,34,35], silicon nanowires/nanotubes [36][37][38], nanosheets [38,39], and 3D porous structures [40,41]. The porous structure can provide a large space to accommodate volume expansion and provide a large surface area for lithium-ion transport from electrolyte to silicon [42].…”