Nano-Structured Silicon Derived from Silica Precursors as Anode Material for Lithium Ion Batteries

Wednesday, 8 October 2014
Expo Center, 1st Floor, Center and Right Foyers (Moon Palace Resort)
M. Schrandt (South Dakota School of Mines and Technology), P. Kolla (SDSM&T), W. Rhine (Aspen Aerogels, Northborough, MA), R. T. Koodali (University of South Dakota), J. Wu, V. Lvovich (NASA Glenn Research Center), R. Cook (Zyvex Technologies, Rapid City, SD 57701), and A. Smirnova (South Dakota School of Mines and Technology)
Silicon is valuable as a high energy density anode material for Li-ion battery applications. However, the high lithium storage capacity leads to extreme volume expansion during lithiation and delithiation that can lead to mechanical deterioration and poor cycle life. To improve cyclability, nano-structured materials can be used to facilitate the volume change without deterioration. By using structured SiO2 precursors, the goal is to reduce SiO2 to Si while maintaining the structure and porosity of SiO2 and thus, mitigating degradation effects during cycling.

Nanostructured Si has been synthesized by Mg vapor reduction from SiO2 precursors [1] (e.g. SiO2 microspheres from 3M, SiO2 aerogel, and mesoporous SiO2 [2]). Following the reduction to Si, the materials were chemically treated in HCl and HF to remove remaining MgO and SiO2 respectively. Figures 1 and 2 confirm the presence of Si in reduced samples and successful removal of MgO and SiO2. TGA/DSC has been used to optimize the reduction time and temperature.  

CV data (Figure 3) and cyclability tests (Figure 4) demonstrate a specific capacity of up to 2065 mAh/g with a low charge transfer resistance (Figure 3, inset).

SEM, TEM, BET, EDS, XRD, and Raman spectroscopy data will be presented for SiO2 and reduced Si to describe chemical composition and morphology. Structure dependent electrochemical properties such as impedance spectroscopy, cyclic voltammetry, galvanostatic discharge, and cycle stability will be presented and discussed.


[1] R. Cook, M. Schrandt, P. Kolla, W. Rhine, R. Koodali, A. Smirnova, MRS Online Proceedings Library,1643 (2014).

[2] D. Zhao, A. Rodriguez, N. M. Dimitrijevic, T. Rajh and R. T. Koodali, J. Physical Chemistry C, 114, 15728 (2010)