Atomic Structural Features of Stacking Faults and Domain Connections in the Li- and Mn-Rich Cathode

作者：Peng Zuo, Pavan Badami, Subhadip Mallick, Jason R. Croy, Daniel P. Abraham, Chongmin Wang · 发表于：ACS Nano · 年份：2025 · DOI：10.1021/acsnano.5c02110 · 被引用次数：15 · 研究领域：Advancements in Battery Materials、Extraction and Separation Processes、Advanced Battery Technologies Research

Li- and Mn-rich layered oxides (LMRs), a class of earth-abundant materials for rechargeable Li-ion battery cathodes, crystallize into layered structures of two different symmetries: C 2/ m represented by Li 2 MnO 3 and R 3̅ m represented by LiMn 0.5 Ni 0.5 O 2 . Fundamental questions about how the C 2/ m and R 3̅ m domains spatially correlate within the same oxide grain and how the C 2/ m stacking faults arrange themselves when this happens still remain. Here, by using integrated differential phase contrast imaging in scanning transmission electron microscopy (STEM-iDPC), we probe the structural and compositional details of a prototypical, cobalt-free LMR material, 0.3Li 2 MnO 3 ·0.7LiMn 0.5 Ni 0.5 O 2 (Li 1.13 Mn 0.57 Ni 0.3 O 2 ). The connection between the C 2/ m and R 3̅ m domains is found to be abrupt, facilitated by the small lattice mismatch between the two structures. Stacking faults in the C 2/ m domains feature atomic plane shifting that accommodates stacking sequence changes, which explains why the stacking faults form in a random manner. Furthermore, a local disordering mechanism was identified to correlate with the C 2/ m stacking faults. Chemically, it is found that Ni coexists with Mn at the transition metal sites within the nominal Li 2 MnO 3 domain. This study demonstrates that STEM-iDPC is a very useful tool for capturing all the elements in a single image, revealing atomic details on domain connections and stacking faults in the LMRs.