Shoring Up the Lithium Ion Batteries with Multi-Component Silicon Yolk-Shell Anodes for Grid-Scale Storage Systems: Experimental and Computational Mechanical Studies

The focus of the current study is to investigate the role of different carbon materials on the mechanical integrity and electrochemical stability of silicon anodes during cycling tests. Because, the electrochemical performance of the lithium ion batteries (LIBs) strongly depends on the mechanical integrity of Si during the lithium insertion process with huge volume change of silicon (similar to 300%) causes undesirable mechanical pulverization of electrodes that results in electrical disconnection between the active materials and the current collector, and eventual fast capacity fading. To this aim, multi- component anode materials were designed with various combinations of Si, Amorphous Carbon (C), reduced Graphene Oxide (rGO), and Carbon Nanofibers (CNFs) for high capacity and long stability LIBs. The stress generations in Si/rGO and Si/C/rGO were calculated after full lithiation of silicon and comparison of the contribution of the carbon shell to the deformation and stress in silicon was evaluated using finite element method in ANSYS design modeler. According to the experimental findings, Si/C/rGO/CNFs electrode has exhibited the highest reversible capacity of about 1750 mAhg(-1) after 200 cycles and the fairly good integral stability against lithium insertion- induced expansion of a silicon. (C) 2017 The Electrochemical Society. All rights reserved.