Jahn–Teller distortion

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LMO

A manganese spinel positive material, LiMn₂O₄, that is cheap, safe and good at high power but suffers manganese dissolution and short life at elevated temperature. It is often blended with NMC rather than used alone.

Particle cracking

Fracture of active-material particles from the volume change of repeated lithium insertion and removal. New surfaces consume electrolyte to form fresh SEI, and fragments that lose contact no longer store lithium.

Phase transition

A change of crystal structure as lithium content varies, which fixes the potential while two phases coexist. Graphite fills in stages, LFP switches between two phases across almost its whole range, and these transitions make the peaks that aging diagnostics read.

Structural degradation

Changes in the crystal structure of a positive material as it cycles: layered oxides can rearrange into spinel or rock-salt phases at the surface, with nickel ions migrating into lithium sites. The new phases block lithium transport and raise resistance.

Transition-metal dissolution

Manganese, nickel or cobalt ions leaching from the positive electrode into the electrolyte, especially at high voltage and temperature or when HF is present. They migrate to the negative electrode and poison the SEI there, accelerating lithium loss.

References & further reading

Further reading on this topic

These sources provide broader context; they are not presented as citations for every statement in this entry.

1. Lithium ion battery degradation: what you need to know

   Physical Chemistry Chemical Physics · 2021

   Topic background · Degradation mechanisms, modes, operational effects and their interactions.