# What's the chemistry behind only charging a Lithium-ion battery to 80% capacity at most, to increase its lifespan?

What's the chemistry behind only charging a Lithium-ion battery to 80% capacity at most, to increase its lifespan?

Over on the Skeptics StackExchange, a question has come up about charging Lithium-ion cells to just 80% of their maximum, in order to extend their lifetime.

Is there a sound basis in chemistry for such a recommendation, and if so, what is it?

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Actually, the chemistry is just the same as chemistry of charging, it's the physics - mechanics of the microstructures collapsing. –  SF. May 22 '13 at 7:52

Most commercially-available lithium-ion batteries use graphite as the anode (negative electrode, where the lithium ions go when the battery is charged) and $Li Co O_2$ as the cathode (positive electrode, where the lithium ions go when the battery is discharged). Both graphite and lithium cobalt oxide have a structure composed of layers stacked on top of one another; the lithium ions fit in between these layers in a process called intercalation.