Microstructure and Li alloy formation of nano-structured amorphous Si and Si/TiN composite thin film electrodes

摘要

Nano-structured silicon-based thin films have been successfully fabricated in amorphous Si and Si/TiN nano-composite forms by pulsed laser deposition method. A direct comparison of the lithium alloying behavior with the microstructure of these two thin films was investigated by measuring the X-ray diffraction, transmission electron microscopy, selected area electron diffraction, X-ray photoelectron spectrometry and electrochemical galvanostatic cycling. The as-deposited Si and Si/TiN composite thin films fabricated at a laser fluence of 2 J/cm~2 were found to be amorphous. The amorphous Si/TiN nano-composite film used as negative electrode exhibited higher capacity and better capacity retention than that of amorphous Si film electrode, which could be attributed to the dispersed Si particles in the nanometer range, forming an amorphous structure of the composite film and the presence of an inactive matrix of TiN.