Solid

In particular, they make it very difficult to use pure lithium metal anodes safely because metallic lithium tends to form dendrites, those tiny needle-like structures that can grow through the separator and potentially short circuit the cell.

Solid state batteries are attractive because, in theory at least, a solid electrolyte could dramatically reduce the fire risk while also enabling the use of lithium metal anodes with much higher energy densities.

In simple terms, more energy storage in less space.

And that's why automakers got so excited.

What it won't do yet, though, is actually mass-produce solid-state batteries that can be bolted to an electric vehicle.

So, you know, still waiting on that one.

Solid Power is another well publicised manufacturer.

They're working closely with BMW and Ford to develop a solid sulphide electrolyte battery that they claim will have a gravimetric energy density of 390 watt hours per kilogram and a volumetric energy density of 930 watt hours per litre.