From the article:

> We’ve always wanted our customers to be able to use their iPhones as long as possible. We’re proud that Apple products are known for their durability, and for holding their value longer than our competitors’ devices.

From their website, linked from the product page: https://www.apple.com/batteries/why-lithium-ion/

Your Apple lithium-ion battery uses fast charging to quickly reach 80% of its capacity, then switches to slower trickle charging. [...] This combined process not only lets you get out and about sooner, it also extends the lifespan of your battery. [...] Apple lithium-ion batteries are designed to hold at least 80% of their original capacity for a high number of charge cycles, which varies depending on the product.