Real-time imaging shows electrolyte flow in lithium-sulfur batteries

A research team at Helmholtz-Zentrum Berlin (HZB) has pioneered the use of operando neutron tomography to observe, in real time, how liquid electrolytes move within practical lithium-sulfur (Li-S) pouch cells containing lean electrolyte. This breakthrough imaging technique allowed the team to visualize electrolyte distribution changes during battery operation without damaging the cells, providing critical insights into the wetting behavior that affects battery performance and longevity. Li-S batteries, known for their potential to deliver over 700 Wh/kg—more than twice the energy density of conventional lithium-ion batteries—are promising for applications in aerospace, robotics, and electric vehicles, partly due to sulfur’s abundance and low cost. The study revealed that incomplete electrolyte wetting, especially during rest phases, leads to unwetted areas that can accelerate battery degradation. However, charging and discharging cycles improved electrolyte homogeneity and sulfur activation, enhancing capacity. The researchers also identified unique “breath in” and “breath out” wetting patterns corresponding