Researchers figuring out how lithium batteries really work

Rechargeable lithium ion batteries power many of today's electronics, from portable devices to cars. These batteries are termed "lithium ion" because they act to hold charges within the battery. Two main processes that are required for the battery to function: lithiation and delithiation during the charge and discharge cycles.

The discharge process, which allows the battery to transfer its electrical energy and power a device, takes place in a material known as lithium iron phosphate (LiFePO₄). Normally, lithium iron phosphate acts as an insulator, but existing ideas describe the discharge process as occurring by transitioning from a pure LiFePO₄ phase into a pure FePO₄ phase.

Now, nearly two decades after the discovery of lithium iron phosphate's utility for batteries, the mechanism through which this discharge takes place is being questioned. New research suggests that there can be a phase in between this transition—called a metastable state—in which the two phases (LiFePO₄ and FePO₄) coexist.