Solar battery

When the first solar cell was made by Bell Labs they called it a solar battery.

This because when the sun was shining it acted like a battery and provided current.

Ironically people are now trying to store solar energy in real batteries.

I wonder how sustainable battery technology is in this context?

Assuming that the energy to make, deploy and recycle the batteries is all renewable the key question is whether the materials used to make the batteries are fully recyclable.

This requirement should constrain battery research efforts.