Solid electrolyte interphases on model Si electrodes studied by electrochemical impedance spectroscopy
Jonas Grill, Jelena Popovic-Neuber
University of Stavanger
Silicon is a promising anode material for lithium batteries due to its high theoretical specific capacity of 4,200 mAh g–1 which is about ten times higher than today’s graphite anodes.(1) In the last years, it has been broadly used in the form of carbon/Si composite material, where this high theoretical capacity has been linked with the high stability of the graphite electrode.(2) The electrochemical behavior of silicon, especially its high volume expansion under current application has received a lot of attention. It is believed that fracture and regrowth of solid electrolyte interphase (SEI) are directly responsible for the accelerated capacity fade.(3-5) Other crucial aspects such as ion transport and SEI growth under open circuit voltage (OCV) and different current/voltage conditions, as well as the influence of native oxide layer on Si, are less known.(6) Previously, we have shown that electrochemical impedance spectroscopy (EIS) is a powerful tool for studies of ion transport and growth of SEI on planar electrodes, including alkali and alkaline earth metals.(7-9) In this work, using similar methodology, we show for the first time that amorphous silicon electrodes cannot be considered inert under near-OCV conditions and in contact with various liquid battery electrolytes. We give a detailed investigation of their behavior, including EIS equivalent circuit models, depending on time, temperature, and the electrolyte chemistry.
- Cui, Nat. Energy 2021, 6, 10, 995-996
- Li et al., Energy Storage Mater. 2021, 35, 550-576
- Je et al., Acc. Chem. Res. 2023, 56, 16, 2213-2224
- Cheng et al., Adv. Funct. Mater. 2023, 33, 26, 2301109
- Kolzenberg et al., Batter. Supercaps 2022, 5, 2, e202100216
- Cao et al., Joule 2019, 3, 3, 762-781
- Popovic, Energy Technol. 2021, 9, 4, 2001056
- Lim et al., J. Mater. Chem. A 2023, 11, 11, 5725-5733
- Lim et al., ACS Appl. Mater. Interfaces 2021,13, 43, 51767-51774