Meaning
Structural failure or dissolution of the protective solid electrolyte interphase on battery electrodes occurs under conditions of high temperature or high cell voltage. Experiencing passivating layer breakdown exposes the highly reactive active material to the organic solvent, triggering further chemical reactions and electrolyte consumption. This degradation reduces the efficiency of the cell and accelerates the loss of active lithium.
Chemical Dissolution
Corrosive species and acid compounds in the electrolyte attack the protective barrier, causing it to dissolve. When passivating layer breakdown occurs, the underlying metal or carbon electrode is no longer insulated from direct chemical reduction, which increases the rate of side reactions. This dissolution is often driven by trace moisture contamination that generates hydrofluoric acid.
Thermal Instability
Elevated temperatures weaken the organic and inorganic compounds that hold the protective film together. Exposure to heat over fifty degrees Celsius triggers passivating layer breakdown, starting a series of self-heating reactions as the exposed electrode reacts exothermically with the electrolyte. If unchecked, this chemical reaction can lead to thermal issues and cell failure.
Capacity Decay
Reformulation of the broken barrier consumes lithium ions that would otherwise carry charge, causing irreversible capacity loss. This decay represents a major failure mode in high-energy lithium batteries.
