Electrochemical lithiation and delithiation properties of ceria–coated silicon electrodes

Abstract

The effect of a ceria (CeO2) coating on the electrochemical performance of a Si negative electrode for use in lithium–ion batteries was investigated. The results of X–ray diffraction analysis, field–emission scanning electron microscopy, and energy–dispersive X–ray spectroscopy showed that CeO2 uniformly coated the entire surface of Si particles. The CeO2–coated Si electrode showed better cyclability than a Si electrode, and the cycle performance of CeO2–coated Si electrode improved with an increase in the coating amount of CeO2. The CeO2/Si (15:85 wt%) electrode maintained a greater discharge capacity at around the 400th cycle, whereas the capacity of the Si electrode began to decay under capacity limitation. While Si–alone and CeO2–coated electrodes had almost the same surface roughness before cycling, the surface roughness of the Si electrode was about 1.6 times greater than that of the CeO2/Si (15:85 wt%) electrode after the 30th cycle; disintegration of the Si–alone electrode was suppressed by CeO2–coating.