Nucleation and Growth Mode of Solid Electrolyte Interphase in Li-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• The solid electrolyte interphase (SEI) is crucial for Li-ion battery performance but its formation mechanism is poorly understood.
• Understanding SEI nucleation and growth is essential for optimizing battery longevity and efficiency.

Purpose of the Study:

• To quantify the nucleation and growth modes of inorganic and organic SEI layers on carbonaceous anodes.
• To investigate the influence of overpotential on SEI growth dynamics.
• To explore strategies for enhancing SEI properties for improved battery capacity retention.

Main Methods:

• Utilized classical nucleation theories combined with in situ atomic force microscopy (AFM) imaging.
• Analyzed SEI formation on carbonaceous anodes under varying electrochemical conditions.
• Investigated the impact of large current pulses during battery formation.

Main Results:

• Inorganic SEI formation follows a mixed 2D/3D growth model, with higher overpotentials favoring 2D growth.
• Organic SEI formation strictly adheres to a 2D instantaneous nucleation and growth model, providing epitaxial passivation.
• Employing large current pulses during formation promotes 2D inorganic SEI growth, leading to enhanced capacity retention.

Conclusions:

• The study elucidates distinct growth mechanisms for inorganic and organic SEI layers.
• Tailoring overpotential and utilizing current pulses can control SEI morphology and improve Li-ion battery performance.
• These findings provide a nanoscale understanding to engineer interphases for advanced electrochemical devices.