Chemistry
Applying the Principles of Electrochemistry to Design High-Performance Batteries
Quick fact
A single lithium-ion cell can deliver up to 4.2 volts—that's about 4.2 joules of energy per coulomb of charge, enough to power a device for hours with just a few grams of material.
Why this is interesting
Your smartphone's battery is a carefully engineered chemical reactor that turns your daily charge into power. But why does one battery die quickly, and another last days?