Spinel structure

Example

Use in Lemonergy

Separate chemistry from form factor.

This is a reference concept. No executable Lemonergy block has been verified for this term.

Connected concepts

Related concepts from the knowledge graph. Connections show context, not cause and effect. Hover or focus a linked term for its definition.

Layered oxide

The crystal structure of LCO, NMC and NCA: close-packed oxygen layers with lithium and transition-metal ions in alternate layers of octahedral sites, so lithium moves in two-dimensional sheets. The structure offers high capacity and voltage but can distort or mix cations when deeply delithiated. Sodium versions are labelled O3 or P2 by their stacking.

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.

LNMO

A nickel-doped manganese spinel, LiNi₀.₅Mn₁.₅O₄, that works at about 4.7 V and contains no cobalt. Its high voltage stresses today’s electrolytes, which is the main obstacle to commercial use.

Lithium titanate

A negative active material, Li₄Ti₅O₁₂, that works at about 1.55 V above lithium, so it never plates lithium and forms almost no SEI. The price is a low cell voltage of about 2.4 V and low energy density, traded for very long life and fast charging.

Olivine structure

The orthorhombic structure of LiFePO₄ and its relatives, in which phosphate groups lock oxygen in place and lithium lies in one-dimensional channels. Strong phosphorus–oxygen bonds make the material thermally stable and long-lived, but one-dimensional diffusion and poor electronic conductivity call for small, carbon-coated particles. LMFP substitutes manganese to raise the voltage.

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

Technical references

1. A reflection on lithium-ion battery cathode chemistry

   Arumugam Manthiram · Nature Communications · 2020

   Technical reference · Layered oxides, spinels and polyanion cathodes; links between composition, structure and performance.