Enhancing conductivity of Si anode enabled by selecting Si particle size for interface stabilized all-solid-state batteries

Silicon (Si) particle with small size used as anode material has been recognized for its ability to reduce the damage caused by volume expansion in liquid lithium-ion batteries. However, whether the same mechanism still exists for different particle sizes of Si in all-solid-state batteries (ASSBs), these have not been systematically investigated. In this work, Si particles with various sizes ranging from 30 to 1000 nm are investigated as regards the effect of Si particle size. It is revealed that the performance of Si particles in ASSBs is influenced by a combination of factors, including uniformity of the Si oxide layer, tap density, and expansion degree, which are all related to size of the Si particles. In order to investigate the effect of different particle sizes of Si, micron, sub-micron, and nano-silicon are set up in this work for electrochemical performance testing of all-solid-state batteries. Among all, sub-micron Si exhibits smaller impedance increase due to its tight contact and fewer voids and cracks after cycle. Such a structure demonstrates excellent conductive network and achieve the high initial Coulombic efficiency (ICE) of Si (78.37