Influence of the SEI Formation on the Stability and Lithium Diffusion in Si Electrodes

Baolin Wu; Chunguang Chen; Dmitri L Danilov; Ming Jiang; Luc H J Raijmakers; Rüdiger-A Eichel; Peter H L Notten

doi:10.1021/acsomega.2c04415

Influence of the SEI Formation on the Stability and Lithium Diffusion in Si Electrodes

ACS Omega. 2022 Aug 30;7(36):32740-32748. doi: 10.1021/acsomega.2c04415. eCollection 2022 Sep 13.

Authors

Baolin Wu^{1

2}, Chunguang Chen^{1

3}, Dmitri L Danilov^{1

4}, Ming Jiang^{1

4}, Luc H J Raijmakers¹, Rüdiger-A Eichel^{1

2}, Peter H L Notten^{1

4

5}

Affiliations

¹ Forschungszentrum Jülich (IEK-9), D-52425 Jülich, Germany.
² RWTH Aachen University, D-52074 Aachen, Germany.
³ LNM, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China.
⁴ Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
⁵ University of Technology Sydney, Broadway, Sydney, NSW 2007, Australia.

Abstract

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 LiClO₄-based electrolytes than in LiPF₆-based electrolytes. This behavior suggests that a denser and more conductive SEI layer is formed in LiClO₄-based electrolytes. In addition, a coating of a Li₃PO₄ 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 m²/s.