Tunable Porosity and Structural Properties of Carbon Aerogels: Adapting Packing Density and Morphology of Dry‐Film Cathodes

The increasing demand for high‐energy‐density storage systems to support green energy technologies has highlighted the limitations of lithium‐ion batteries and spurred interest in lithium‐sulfur solid‐state batteries (LS‐SSBs), as they offer significant advantages, such as high theoretical energy densities and improved safety. Despite intense research in the recent years, there is a lack of understanding regarding a favorable carbon structure as a sulfur host in LS‐SSBs. This study investigates the use of carbon aerogels (CAs) with adaptable porosity and mechanical properties as conductive matrices in LS‐SSB cathodes. Two different CAs are examined: a brittle, mesoporous aerogel (p‐CA) and a flexible, macro‐ and microporous aerogel (f‐CA). High sulfur utilization (∼1500 mAh g S −1 ) is achieved using p‐CA, but it suffers from low Coulombic efficiency and reversibility. Conversely, f‐CA exhibits lower sulfur utilization but improved cycling stability. The combination of both aerogels results in a higher packing density of the LS‐SSB cathode. High sulfur utilization and enhanced long‐term stability are realized for the mixed cathode. These results demonstrate the potential of CAs as a customizable, scalable host matrix for LS‐SSBs, enabling improved cathode morphology and electrochemical performance through controlled tuning of their structural and mechanical properties.