Open AccessMicrostructural Observations of “Single Crystal” Positive Electrode Materials Before and After Long Term Cycling by Cross-section Scanning Electron Microscopy
Author(s) -
Yulong Liu,
Jessie Harlow,
J. R. Dahn
Publication year - 2020
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/ab6288
Subject(s) - scanning electron microscope , electrode , materials science , crystallite , single crystal , crystal (programming language) , lithium (medication) , microscopy , chemical engineering , analytical chemistry (journal) , composite material , crystallography , metallurgy , chemistry , optics , physics , medicine , engineering , chromatography , computer science , programming language , endocrinology
Single crystal LiNi 0.5 Mn 0.3 Co 0.2 O 2 (SC532), LiNi 0.6 Mn 0.2 Co 0.2 O 2 (SC622) and LiNi 0.8 Mn 0.1 Co 0.1 O 2 (SC811) electrodes were retrieved from heavily cycled commercial-grade pouch cells at 4.3 V for cross-section scanning electron microscopy (SEM). SEM images indicated the single crystals showed very little microcracking, thought by many researchers to be one of the main reasons for cell degradation when polycrystalline materials are used. SEM images of electrodes from heavily cycled cells were compared to those from fresh cells which showed little visual difference. Parallel microcracks within very few single crystal particles were observed for both fresh and heavily cycled materials and are thought to be caused during the electrode calendaring process. It is believed by the authors that single crystal materials are highly promising positive electrode materials for high energy density and long cycle life lithium-ion cells.