Lithium-ion batteries are ubiquitous—as is their gradual degradation over the lifetime of a gadget. Now, using a new imaging technique, a team of researchers shows what happens deep within li-on cells as they charge and discharge.

The team, from the Department of Energy's Joint Center for Energy Storage Research, has created what they call an operando electrochemical stage. Using this—as well as a cutting-edge electron microscope—they're able to record at nanoscale-resolution what happens inside li-on cells as lithium ions are deposited on to an electrode and then dissolve back off.

You can see how, over time, lithium becomes irreversibly deposited to the electrodes. These build ups are called dendrites and they're what causes the batteries to degrade and ultimately fail over time. By being able to image electrodes in this way, researchers will be able to more quickly assess new battery technologies, to establish what works and what doesn't. And, hopefully, make us some batteries that last a little longer. [Nano Letters via PhysOrg]