Detrimental electrochemical behavior caused by excessive high pressure on Li-ion pouch-type full cell

Abstract

Pressure on electrodes in cells is crucial for improving their active material density and electronic conductivity. A single-layer pouch cell (60 mAh) was fabricated to study the electrochemical effects of external pressures ranging from 0 to 3 MPa. The high-pressure cell at 3 MPa presented poor capacity retention owing to Li plating and pore-clogging on the graphite electrode. However, the optimized pressed cell did not hinder Li-ion transport in the graphite anode and underwent 200 cycles with 82 % capacity retention. External pressure impacts the contact between the electrodes and electrolyte; however, excessive pressure makes it difficult to supplement Li ions from the electrolyte into the graphite anode, resulting in increased polarization, electrolyte side reactions, and Li-metal deposition.

Keywords

• Li-ion battery
• External pressure
• Capacity-fading
• Li plating
• Pouch cell