Silicon (Si) is an attractive anode material for Li-ion
batteries
(LIBs) due to its high theoretical specific capacity. However, the
solid–electrolyte interphase (SEI) formation, caused by liquid
electrolyte decomposition, often befalls Si electrodes. The SEI layer
is less Li-ion conductive, which would significantly inhibit Li-ion
transport and delay the reaction kinetics. Understanding the interaction
between the SEI components and Li-ion diffusion is crucial for further
improving the cycling performance of Si. Herein, different liquid
electrolytes are applied to investigate the induced SEI components,
structures, and their role in Li-ion transport. It is found that Si
electrodes exhibit higher discharge capacities in LiClO
4
-based electrolytes than in LiPF
6
-based electrolytes.
This behavior suggests that a denser and more conductive SEI layer
is formed in LiClO
4
-based electrolytes. In addition, a
coating of a Li
3
PO
4
artificial SEI layer on
Si suppresses the formation of natural SEI formation, leading to higher
capacity retentions. Furthermore, galvanostatic intermittent titration
technique (GITT) measurements are applied to calculate Li-ion diffusion
coefficients, which are found in the range of 10
–23
–10
–19
m
2
/s.