Polyanionic cathode

Example

Use in Lemonergy

Do not carry lithium-ion assumptions into every chemistry.

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

Connected concepts

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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.

LFP

A positive electrode material, LiFePO₄, giving cells a nominal voltage around 3.2 V, long cycle life and good thermal stability, but less energy per kilogram than nickel-rich oxides. Its flat voltage curve makes state of charge hard to read from voltage alone.

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.

Prussian blue analogue

An open-framework compound, AₓM[Fe(CN)₆], in which iron–cyanide units and another metal form a cubic cage with wide channels for large ions. Made at low temperature from cheap elements, its sodium-rich form, Prussian white, is a leading sodium-ion cathode. Water trapped in the lattice degrades cells, and the cyanide groups raise questions in thermal runaway.

Sodium-ion battery

A cell built like a lithium-ion cell but shuttling sodium ions, usually between a hard-carbon negative electrode and a layered oxide or Prussian-blue positive. It uses no lithium, cobalt or copper, at the cost of lower energy density.

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. Promise and reality of post-lithium-ion batteries with high energy densities

   Jang Wook Choi, Doron Aurbach · Nature Reviews Materials · 2016

   Topic background · Post-lithium-ion materials and battery concepts, including practical cell-level limitations; historical 2016 perspective.

2. DOE/EPRI 2013 Electricity Storage Handbook in Collaboration with NRECA

   Sandia National Laboratories · 2013

   Topic background · Storage technologies and grid services. The publisher notes that its historical cost and deployment figures are outdated.