In-situ nanoscale insights into the evolution of solid electrolyte interphase shells – EurekAlert

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IMAGE: The SEI shells evolution processes and degradation mechanism at the electrode/electrolyte interface. view more 

Credit: ┬ęScience China Press

The interfacial decomposition products forming the so-called solid-electrolyte interphase (SEI) during the first charging/discharging significantly determine the electrochemical performances of lithium (Li) batteries. To date, the dynamic evolutions, chemical compositions, stabilities and the influencing factors of the SEI films have been captured tremendous attentions.

It’s noted that, in contrast to the SEI film formation at the surface of electrodes, a kind of SEI shells usually conformally forms at the outmost layer of the on-site deposited Li once the freshly deposited Li contacts with the electrolyte, which could directly influence Li nucleation, growth behaviors and electrochemical properties at the electrode/electrolyte interface.

Furthermore, the chemical/morphological instabilities of the on-site formed SEI shell pose challenges for the in-situ characterizations. Directly capturing the dynamic evolution of the SEI shells is crucial to interprete their impacts on the anode/elelctrolyte interface and battery performances.

The electrochemical atomic force microscopy (EC-AFM) enables the real-time characterization of the morphology change, mechanical modulus and potential/current distribution at the electrode/electrolyte interface under working conditions, providing an important in-situ analysis method with high spatial resolution for exploring the dynamic evolution of the on-site formed SEI shell on the
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