Silicon-Encapsulating Spherical Carbon Microbeads for Lithium ion Batteries

Abstract

Recently, remarkable improvements in the electrochemical performance of Si materials have been achieved through several strategies including the use of a buffer matrix such as Si/carbon composites and control of the morphology. However, the inherent volume change of Si still induces electrode expansion and external cell deformation, although the electrical contact loss is strongly inhibited. The cell deformation is the critical factor limiting the commercialization of Si-based anode materials, and is as important as electrochemical performance from a practical point of view. An acceptable degree of volume change for the electrodes is about 10 %, similar to that of commercialized graphite electrodes. A few approaches have been taken to alleviate cell deformation, including control of electrode porosity and the use of functional binders. In this paper, Silicon-Encapsulating Spherical Carbon Microbeads are synthesized not only to inhibit the electrode degradation caused by electrode thickness change during cycling, but also to increase tap density of electrodes