Direct In Situ Determination of the Surface Area and Structure of Deposited Metallic Lithium within Lithium Metal Batteries Using Ultra Small and Small Angle Neutron Scattering

Despite being the major cause of safety and performance issues in lithium metal batteries, experimental difficulties in quantifying directly the morphology of lithium deposited at electrode surfaces have meant that the mechanism of metallic lithium growth within batteries remains elusive. This study demonstrates that quantitative detail about the morphology of metallic lithium within batteries can be derived non-destructively and directly using in situ ultra-small and small-angle neutron scattering. This information is obtained over a large electrode area in cells where lithium deposition processes are typical of real-world applications. Complex variations of surface area and interfacial distances 1-10 mu m and 100-300 nm are revealed in size that are influenced by current density and cell cycling history, providing valuable insight into the growth of metallic lithium features detrimental to battery performance. Such quantitative insight into the process of lithium growth is required for the development of safer high-performance lithium metal batteries. Small and ultra-small angle neutron scattering is used to quantitatively reveal the microstructure and surface area of deposited metallic lithium in batteries. The in situ study captures changes in morphology and surface area and reveals variations that depend on cell cycling history, necessary to understand the mechanism of metallic lithium growth in real-world applications.image

Automated summary

This study quantitatively investigates the morphology of lithium metal deposition in batteries using in situ ultra-small and small-angle neutron scattering. The research reveals the complex variations of surface area and interfacial distances influenced by current density and cell cycling history, providing valuable insights into the growth of metallic lithium features detrimental to battery performance. The findings are crucial for the development of safer and high-performance lithium metal batteries.