Multipath conduction and large capacity silicon-based anodes for high stabilizing lithium-ion batteries

Ultrahigh specific capacity silicon is considered as a potential anode candidate for lithium-ion batteries (LIBs). In order to reduce the influence of the large volume expansion and poor conductivity of silicon, a few silicon nanoparticles are now used in commercial anodes, which increases costs and weakens the overall specific capacity. Here, we used low-cost aluminum-silicon alloys as raw materials to obtain porous silicon (pSi) particles by simple chemical etching. Then, Ag doped porous silicon/graphite (Ag-pSi/G) composite was prepared by depositing ultrafine Ag nanoparticles and mixing low-quality graphite. The large specific surface area, Ag nanoparticles and graphite provide multiple electron transport pathways in Ag-pSi/G, so they greatly increase the conductivity of the Ag-pSi/G and effectively reduce its volume expansion. The Ag-pSi/G composite shows high initial charging capacity (3313 mAh g(-1) at 0.1 A g(-1)) and initial coulombic efficiency (82.2%), and stable reversible specific capacity of 770 mAh g(-1) over 300 cycles at 1 A g(-1). This simple and scalable preparation process provides a new thought for the broad application of micron silicon materials in the high-performance LIBs.

Automated summary

Low-cost aluminum-silicon alloys were used to obtain porous silicon particles, which were then combined with ultrafine Ag nanoparticles and low-quality graphite to prepare Ag-doped porous silicon/graphite composite. This composite showed improved conductivity and reduced volume expansion, leading to high initial charging capacity and stable reversible specific capacity over multiple cycles.