Accelerated Degradation in a Quasi-Single-Crystalline Layered Oxide Cathode for Lithium-Ion Batteries Caused by Residual Grain Boundaries

• Published in: Nano letters Vol. 22; no. 9; pp. 3818 - 3824
• Main Authors: Zhang, Rui, Wang, Chunyang, Ge, Mingyuan, Xin, Huolin L.
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 11.05.2022
• Subjects: ADVANCED PROPULSION SYSTEMS; degradation; ENERGY STORAGE; grain boundary; layered oxide; lithium-ion battery; MATERIALS SCIENCE; Single-crystalline cathode; single-crystalline cathode; degradation; lithium-ion battery; layered oxide; grain boundary
• ISSN: 1530-6984; 1530-6992; 1530-6992
• DOI: 10.1021/acs.nanolett.2c01103

The rapidly growing demand of electrical vehicles (EVs) requires high-energy-density lithium-ion batteries (LIBs) with excellent cycling stability and safety performance. However, conventional polycrystalline high-Ni cathodes severely suffer from intrinsic chemomechanical degradation and fast capacity fade. The emerging single-crystallization strategy offers a promising pathway to improve the cathode’s chemomechanical stability; however, the single-crystallinity of the cathode is not always guaranteed, and residual grain boundaries (GBs) could persist in nonideal synthesis conditions, leading to the formation of “quasi-single-crystalline” (QSC) cathodes. So far, there has been a lack of understanding of the influence of these residual GBs on the electrochemical performance and structural stability. Herein, we investigate the degradation pathway of a QSC high-Ni cathode through transmission electron microscopy and X-ray techniques. The residual GBs caused by insufficient calcination time dramatically exacerbate the cathode’s chemomechanical instability and cycling performance. Our work offers important guidance for next-generation cathodes for long-life LIBs.