Lithium titanate batteries

These batteries are safer than other Lithium batteries, have a slightly lower power density but last about 10x as much as LFP batteries batteries (20.000 versus 2.000). Another advantage is that they can be charged at much higher rates due to the nano-electrodes.

Given that currently well-managed LFP-batteries last as long as solar panels and the progress in battery technology advances quickly, it might be wiser to stick with batteries that need to be replaced together with solar panels so that a much high net renewable production may be achieved.

http://www.ev-power.eu/LTO-Tech/

https://en.wikipedia.org/wiki/Lithium%E2%80%93titanate_battery