Photoacoustic Imaging of Lithium Metal Batteries

To better understand and overcome the lithium (Li) dendrite problem in Li metal batteries, great efforts have been made to reveal dendrite growth processes using various imaging modalities. However, because of being almost invisible to electrons and X-rays, directly imaging Li metal with the required contrast and spatial and temporal resolutions has always been the challenge. Here, we show that, by exploiting photoacoustic effect, microscale-resolution three-dimensional structure of Li protrusions inside the glass fiber separator of a Li/Li liquid electrolyte symmetric cell can be clearly visualized with high contrast within minutes by photoacoustic microscopy, demonstrating the potential for observing dendrite growth.