Development of silicon/carbon nanocomposite anodes from simple precursors for lithium-ion batteries

Official URL: https://risc01.sabanciuniv.edu/record=b2708487_(Table of contents)

Silicon is an attractive material for the anode in lithium-ion batteries due to its low delithiation potential (0.4 V), high gravimetric and volumetric capacity, and abundance in nature. However, the use of siliconbased anode imposes challenges in the performance of lithium-ion batteries that can lead to their poor capacity retention. These challenges include (1) pulverization of silicon under significant volume expansion and contraction during alloying and dealloying with lithium, (2) instability of the interphase formed between silicon and electrolyte, and (3) low electrical conductivity of silicon. Reducing the size of silicon particles to the nanoscale has been proven to prevent particle pulverization. However, the other issues can be addressed by making composites of silicon nanoparticles and carbon. Nevertheless, it is still challenging to produce nanoscale silicon and its well-dispersed nanocomposites in carbon using a cost-effective and scalable method. In this dissertation, we focus our research on fabricating nanoscale silicon materials from simple precursors. First, the synthesis of silicon nanoparticles from a silicon dioxide mineral through saltmediated magnesiothermic reduction was investigated. Then, electrospinning of a hybrid solution prepared by mixing various silicon precursors and polyacrylonitrile as a carbon source was explored. Finally, lowtemperature aluminothermic reduction of silicon dioxide-carbon nanocomposite fibers was investigated. The electrochemical performance of the developed silicon nanostructures and silicon-carbon nanocomposite fibers was validated.