The electrochemical and compositional changes of a solid electrolyte interphase (SEI) layer formed on the surface of silicon thin film are investigated in order to determine the effect of the content of fluoroethylene carbonate (FEC) additive in the electrolyte. Comparisons are made with FEC-free electrolyte, in which the major components are (CH2OCO 2Li)2 and Li2CO3. The (CH 2OCO2Li)2 and Li2CO3 of the SEI layer in the FEC-containing electrolyte decreases, and polycarbonate and LiF increase relatively with the repression of -OCO2Li groups. The additive affects the composition of the SEI layer, which leads to lower resistance. The electrochemical performance regarding cycle retention, coulombic efficiency, rate capability, and discharge capacity in the FEC-containing cell are significantly enhanced compared to that of the FEC-free electrolyte. The observed optimum FEC concentration in the electrolyte is 1.5%, due to the reduced charge transfer and SEI resistance in our experimental range.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea Grant funded by the Korean Government (MEST) ( NRF-2010-C1AAA001-2010-0028958 ).
- Amorphous materials
- Chemical vapor deposition
- Thin films
ASJC Scopus subject areas
- Materials Science(all)
- Physics and Astronomy(all)