Electrochemical lithiation and delithiation properties of ceriaecoated silicon electrodes

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.