A Systematic Study Of Stabilization Methods For Mechanically Milled Silicon-Carbon Nanocomposite Anode Materials

Open Access
Author:
Howlett, Giles Ford
Graduate Program:
Mechanical Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
April 18, 2014
Committee Members:
  • Donghai Wang, Thesis Advisor
Keywords:
  • Silicon Anode
  • Silicon
  • Silicon Carbon Nanocomposite
  • Lithium Ion Battery
  • Anode
Abstract:
With a theoretical specific capacity of more than 4000 mAh/g, an order of magnitude improvement over the capacity of graphitic carbon, silicon has been examined as an improved anode material for lithium ion batteries. In this thesis, the performance of a silicon-carbon nanocomposite material produced via a simple mechanical milling process is examined and optimized through the systematic exploration of several important parameters. Commercially available silicon nanoparticles in a 1:1 ratio to conductive carbon are used to achieve a gravimetric energy density of almost 1000 mAh/g after 150 cycles following a study of silicon-carbon ratios, binder materials, electrolyte composition, and silicon nanoparticle size. Additionally, the effect of the electrolyte additive fluoroethylene carbonate on the silicon anode during cycling was studied utilizing high resolution SEM imagery of post cycling electrodes and the mechanical destruction of the silicon anode cycled without the FEC additive in the electrolyte is clearly contrasted with the nearly pristine structure of an electrode cycled in electrolyte containing 10% FEC.