Johanna Nelson uses powerful X-ray imaging to study lithium-sulfur batteries, a promising technology that could some day power electric vehicles. Working with scientists at SLAC and Stanford University, Nelson took microscope snapshots of individual sulfur particles -- the first real-time imaging of a lithium-sulfur battery in operation. Previous studies using standard electron microscopes showed that large amounts of sulfur disappears from the cathode after cycling, causing the battery to die. But Nelson's team showed that sulfur particles mostly remain intact. Their results could could help scientists develop commercially viable lithium-sulfur batteries for electric cars.