Scientists have figured out why lithium sulfur batteries are slow. In this respect informs Berlin Material and Energy Center named after Helmholtz.
Solid-state lithium sulfur batteries are considered a promising replacement for modern lithium-ion batteries, as they store energy at a higher density and are not prone to ignition and explosion. However, for reasons that were inexplicable until recently, the experimental batteries produced very little power – that is, they gradually discharged.
Robert Bradbury and colleagues observed this battery in action and monitored the transport of lithium ions between the anode and cathode in a solid-state lithium-sulfur battery. Because lithium was difficult to detect with X-ray methods, the battery instead “flashed” with a stream of neutrons.
“From the neutron radiography data, we see that there is a reaction front of lithium ions running across the entire composite cathode. This confirms the negative impact on the process of low ionic conductivity of the material,” the authors write. In other words, charge carriers (ions) move very slowly through the material. It was also possible to see condensed lithium next to the current collector during charging. This causes a reduction in capacity because only some of the lithium is carried back when the battery is charged.
The study reveals a previously overlooked bottleneck in solid-state battery development, showing limitations in cathode composites due to slow ion transport. The task now is to make the ions move faster through the cathode composition.
previous experiment showedThe disappearing balloon trick can’t fool the monkeys.