I believe this is approximately how modern rechargeable devices work in order to get so much life out of lithium ion batteries.

Maximum charge state is some percentage below the batteries physical maximum, and maximum discharge is state is above the batteries physical minimum.

There's a bit in this Wikipedia article[1] that state charging Li-ion batteries beyond 80% can drastically accelerate battery degradation.

1. https://en.wikipedia.org/wiki/Lithium-ion_battery#Charge_and...