Electron Beam-Induced Effects on a Ni-Rich Layered Cathode Material: A Comprehensive Investigation Using STEM and EELS
Jong Hyeok Seo, Sungmin Na, Sang Jung Ahn, Kwangjin Park, Sooheyong Lee, Joohyun Lee, Ji‐Hwan Kwon
Abstract
Scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) are commonly used to study the structural properties of lithium-ion battery electrode materials. However, electron beam damage poses a challenge to the interpretation of data in electron beam-sensitive materials. In this study, we investigated electron beam effects on the cathode material Li 1.05 Ni 0.88 Co 0.08 Mn 0.04 O 2 (Ni-rich NCM) by varying the electron probe currents. Using a low electron probe current of 5 pA (equivalent to an electron dose of 4 × 10 5 e – /Å 2 ), no significant changes were detected in the STEM images or EELS spectra. In contrast, at higher currents above 70 pA (electron dose: 6 × 10 6 e – /Å 2 ), significant sputtering damage was observed, along with changes in the O K-edge and Ni L-edge structures. These electron beam effects, such as sputtering damage and phase transition, occur under the moderate electron probe beam condition (∼10 6 e – /Å 2 ) near the surface of the Ni-rich NCM. This study establishes a crucial experimental framework for investigating radiation-sensitive materials while emphasizing the importance of the radiation-induced effects in energy materials.