3D tomography of porous battery electrodes with in-situ contrast enhancement

• Contrast-enhanced FIB-SEM tomography of porous battery electrodes was achieved via in-situ pore filling • 3D Monte Carlo simulations estimated the in-situ deposited contrast agent depth within the electrode pores • Accurate 3D reconstructions of all electrode constituents were obtained from contrast-enhanced tomography data Lithium-ion batteries have emerged as the most common energy storage technology. Yet, the characterization and optimization of battery electrode’s morphology is still an underdeveloped route for improving their performance. Particularly, the electrode’s porous microstructural arrangement defines electron and ion transport, as well as electrochemical processes which ultimately determine the battery performance. In this respect, three-dimensional (3D) Focused Ion Beam - Scanning Electron Microscope (FIB-SEM) tomography allows to reconstruct the electrode internal 3D morphology down to ∼10 nm resolution. However, low contrast between electrode constituents, especially the carbon-binder and pores, hinders reliable 3D electrode volume reconstruction. To overcome this issue, we demonstrate contrast-enhanced FIB-SEM tomography of porous battery electrodes via in-situ pore filling at µm depths with platinum, using Gas-Injection System (GIS) electron-induced deposition. This contrast enhancement strategy improved the confidence for pore identification and derived volume fractions, opening the door to precise 3D characterization of battery electrodes, towards their optimization.