- SEI layer on anode grows thicker over time (a. k. a. passivation)
- Lithium plating
- Crystal formation, dendritic growth (preconditioned by lithium plating)
- Metals from cathode can dissolve into electrolyte, reducing the number of sites for Lithium ions to intercalate
- Corrosion (e. g. formation of Lithium oxide when overdischarging the cell, or corrosion of other metals dissolved from the cathode material)
- Metal oxides have high resistance (not very conductive)
- Over-discharge creates latent short-circuit risk: Corrosion of copper current collector, releasing positive Cu+ ions into the electrolyte, when a cell is severely discharged (to about 1.5V), at least locally.