In Situ Monitoring of Thermally Induced Effects in Nickel-Rich Layered Oxide Cathode Materials at the Atomic Level

• DOI: 10.1021/acsami.0c16685
• Publication Date: 2020-12-09T19:50:39Z
• Authors: Anuj Pokle; Shamail Ahmed; Simon Schweidler; Matteo Bianchini; Torsten Brezesinski; Andreas Beyer; Jürgen Janek; Kerstin Volz
• Keywords: Atomic units; Nanopore

The thermal stability of cathode active materials (CAMs) is major importance for the safety lithium-ion batteries (LIBs). A thorough understanding how commercially viable layered oxide CAMs behave at atomic length scale upon heating indispensable further development LIBs. Here, structural changes Li(Ni0.85Co0.15Mn0.05)O2 (NCM851005) elevated temperatures are studied by in situ aberration-corrected scanning transmission electron microscopy (AC-STEM). Heating NCM851005 inside microscope under vacuum conditions enables us to observe phase transitions and other high spatial resolutions. This has been primarily possible establishing low-dose beam STEM. Specific focus put on evolution inherent nanopore defects found primary grains, which believed play an important role LIB degradation. onset temperature be ∼175 °C, resulting transformation from a rock-salt-like structure, especially internal interfaces, increasing intragrain inhomogeneity. reducing environment heat application lead formation subsequent densification {003}- {014}-type facets. In light these results, postsynthesis electrode drying processes applied heat, example, preparation solid-state batteries, should re-examined carefully.