Battery death due to aging

Over the life time of the cell the morphology of the components will change, with effects that are detrimental to the functioning of the cell.

• The crystals in the cell grow larger, increasing the impedance,
  
• Metallic dendrites grow on the cells causing the electrodes to swell, forcing them closer together and increasing the self-discharge,
  
• The dendrites may penetrate the separator giving very high self discharge, or even a short circuit.

Eventually, the internal impedance and the self discharge will be so high that the battery is no longer usable.

Metallic dendrites (Click micrograph for details).