Porous nanocomposite anodes of silicon/iron silicide/3D carbon network for lithium-ion batteries

Abstract

Silicon/iron silicide/three-dimensional (3D) carbon nanocomposite anodes with tunable pore structures have been prepared by a simple and environmentally benign method, which can be used to control not only the internal porosity of agglomerated anode particles, but also the density of their 3D network-like carbon coatings by varying the volume fraction of NaCl pore template. As the amount of NaCl increases, the total particle porosity and density of the carbon coating increase as well. The presence of pores in the agglomerated particles and carbon network mitigate the structural damage caused by the volume expansion during the lithiation and delithiation of active silicon inside the nanocomposite aggregates. Consequently, the electrodes fabricated from the nanocomposites with high NaCl contents exhibit enhanced electrochemical performance. After increasing the NaCl volume fraction to 46%, the capacity retention of the electrode after 100 cycles increases by more than 25% with respect to the value obtained for the composite without added NaCl. In addition, increasing the NaCl content also improves the Coulombic efficiency and rate capability of the anode. (C) 2018 Elsevier B.V. All rights reserved.