What causes a lithium ion battery to degrade?

Figure 2 outlines the range of causes of degradation in a LIB, which include physical, chemical, mechanical and electrochemical failure modes. The common unifier is the continual loss of lithium (the charge currency of a LIB). 3 The amount of energy stored by the battery in a given weight or volume.

How does lithium loss affect battery capacity?

Both modes of lithium loss reduce the charge “currency” or lithium inventory, and thus the battery’s capacity, because there will be a diminished amount of lithium freely available to convey charge between the positive and negative electrodes.

Why do batteries lose energy?

The electrolyte is supposed to move only lithium ions, but hydrogen protons and electrons break off of molecules in the electrolyte and leak into the outer layers of the cathode, triggering a cascade of unwanted reactions that reduce battery life. Past explanations of energy loss in batteries focused on the movement of lithium ions.

What happens if a lithium battery fails?

(ii) In a worst-case scenario, the metallic lithium can grow into branch-like structures called dendrites, which can protrude through the insulating separator and short-circuit the battery. This can cause a catastrophic failure mode, as has been seen in high-profile EV fires covered in the media.

Why do lithium AA batteries lose power?

Lithium AA batteries, despite sharing a nominal voltage of 1.5V, maintain their voltage almost consistently until the very end, where the drop-off is sudden and abrupt. This sharp decline explains why devices relying on lithium AA batteries might indicate a nearly full charge one moment, only to lose power entirely moments later.

Can lithium ions damage a battery?

Lithium ions must be able to move freely and reversibly between and within the battery’s electrodes. Several factors can impede this free movement and can cause a battery to prematurely age and degrade its state-of-health (SoH). Over time, successive charging and discharging causes damage to the battery’s materials.