Levelized Electrode Utilization of Silicon-Enriched Pouch-Type Lithium-Ion Batteries from External Stress-Induced...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Silicon (Si) negative electrodes offer high capacity for lithium-ion batteries but suffer from inhomogeneous utilization in large pouch cells.
• Localized high electrical resistance near current collector tabs leads to uneven lithiation and degradation.

Purpose of the Study:

• To investigate the effect of external pressure on Si negative electrode utilization in pouch cells.
• To mitigate sectional failure and improve electrochemical performance.

Main Methods:

• Analysis of electrical resistance distribution in pouch cells.
• Investigating the impact of external pressure on Si electrode overpotential and volumetric expansion.
• Evaluating electrochemical performance and degradation mechanisms.

Main Results:

• Uneven Si utilization and polarization growth were observed in large pouch cells due to resistance gradients.
• External pressure constrained volumetric expansion, increasing overpotential for near-tab materials.
• External pressure application equalized Si utilization across the electrode footprint.

Conclusions:

• External pressure effectively modulates overpotential, promoting uniform Si utilization.
• This method mitigates sectional failure in Si negative electrodes, enhancing battery cycle life and performance.