Synthesis of Porous Si/C Composite Nanosheets from Vermiculite with a Hierarchical Structure as a High-Performance Anode for Lithium-Ion Battery

Abstract

Silicon nanosheets are fascinating anode materials for lithium-ion batteries because of their high specific capacities, structural stability, and fast kinetics in alloying/dealloying with Li. The nanosheets can be synthesized through chemical vapor deposition (CVD), topochemical reaction, and templating method. After coating with a carbon nanolayer, they exhibit enhanced electrochemical performance. However, it is challenging to synthesize ultrathin carbon-coated silicon nanosheets. In this work, porous silicon/carbon (pSi/C) composite nanosheets are synthesized by reducing the carbon-coated expanded vermiculite with metallic Al in the molten salts. The as-prepared pSi/C nanosheets retain the layered nanostructure of vermiculite, with a thickness of less than 50 nm. The carbon nanolayer serves as the diffusion barrier and mechanical support for the growth of mesoporous silicon nanosheets. The anode of pSi/C nanosheets achieves remarkable electrochemical performance, exhibiting a reversible capacity of 1837 mA h g −1 at 4 A g −1 and retaining 71.5% of the initial capacity after 500 cycles. The process can be extended to the synthesis of the pSi/C composite nanotube by using other carbon-coated silicate templates such as halloysite.

Advanced Materials Prepared via Metallic Reduction Reactions for Electrochemical Energy Storage

“…(c) Reproduced with permission. [ 93 ] Copyright 2019, American Chemical Society. (d) Reproduced with permission.…”

“…In addition, Zhang's group [ 92 ] prepared porous Si and porous Si@C at 210–220 °C by adopting the eutectic mixture of AlCl 3 and ZnCl 2 as mediator in Al reduction system (Figure 14b). Bao and co‐workers [ 93 ] obtained porous Si/C (pSi/C) nanosheets using vermiculite as precursor for low temperature molten salt Al reduction at 300 °C (Figure 14c). Zhu et al [ 94 ] also introduced a low temperature molten salt Mg reduction method to produce Si/SiO x @C material (Figure 14d).…”

Facile and Scalable Synthesis of Si@void@C Embedded in Interconnected 3D Porous Carbon Architecture for High Performance Lithium‐Ion Batteries

“…Chen et al. has reported multilayered Si nanoparticles/reduced graphene oxide hybrid, which shows an outstanding lithium storage performance with high reversible capacity of 2300 mA h g −1 at 0.05 C. [ 19 ] Although these Si/C hybrid electrodes have good electrochemical cycling life, the synthesis processes have a series of shortcomings, such as expensiveness for large scale production, use of sophisticated equipment, low production yield, and long synthesis time. [ 20–22 ] Realization of easy and scalable production of Si@void@C/C composites with the decent performance is a crucial step toward practical applications.…”

Phenolic Resin-coated Porous Silicon/carbon Microspheres Anode Materials for Lithium-ion Batteries

“…Porous silicon can shorten the lithium-ion diffusion path，alleviate the bulk expansion effect and improve the electrochemical performance [22,23] because of its 3D pore structure. The coated carbon layer on the porous silicon not only provides buffer for the volume expansion of silicon, but also enhances the electrical conductivity of the material [24][25][26][27][28][29][30].…”