Rechargeable lithium ion are ubiquitous in modern mobile electronic gadgets but despite claims that they do not suffer from the debilitating "memory effects" of their nickel-cadmium predecessors, they do wear out with repeated charge cycles. Now, researchers at Pacific Northwest National Laboratory (PNNL) in Richland, Washington, USA, have demonstrated using powerful microscopy techniques that eruptions of lithium at the tip of a battery's electrode, cracks in the electrode's body, and a coat forming on the electrode's surface reveal how recharging a battery many times ultimately leads to its demise and an inability to recharge it again. "This work is the first visual evidence of what leads to the formation of lithium dendrites, nanoparticles and fibers commonly found in rechargeable lithium batteries that build up over time and lead to battery failure," explains lead scientist Nigel Browning. "Once you can image this," he says, "why cycle a battery for days and days and days when you know how quickly the battery decays? Now we can cut down on cycling and move on to testing individual characteristics of new battery chemistries."