In-situ observation of volume expansion behavior of a silicon particle in various electrolytes

The understanding of volume change behavior of a silicon particle is necessary to design a new negative electrode using silicon active materials. Here, the drastic volume expansion behavior of a silicon particle with μm-size was in-situ observed in order to find apparent volume expansion ratio during the first lithiation in several kinds of electrolytes by using single particle measurement technique. This technique is very useful not only to find the intrinsic electrochemical properties but also to observe the volume change behavior of one electrode active materials particle. The apparent volume expansion ratio of a silicon particle was larger than theoretical expectation because the measured silicon particles were secondary particles which contained some space between the primary particles. In addition, the volume expansion behavior during the first charging was independent on the Li salt, solvents and the applied charging current density.