Performance improvement of cathode materials represent one of the most critical technological challenges for lithium ion batteries (LIBs), as existing cathode materials exhibit underachieved thermal stability and severe capacity loss. Lithium transition metal (TM) oxides, in particular, Li(NixMnyCoz)O2 (NMC, x+y+z = 1) are the most promising candidates as cathode materials with the potential to increase energy densities and lifetime, reduce costs, and improve safety. In order to further boost Li storage capacity, a great deal of attention has been directed toward developing Ni-rich layered TM oxides. However, high Ni content introduces some critical issues into layered oxide materials, including poor thermal stability, structural disorder (Li/Ni mixing), microcracks and transition metal dissolution. In this talk I will discuss our recent mechanistic studies of layered oxide cathodes. Through advanced X-ray techniques (including XRD, XAS, and XRF) and electron microscopy, we systemically investigated the thermal stability and Li/Ni disorder of layered oxide cathode. Further, well-defined model system was employed to compare the electrochemical performance and structural stability of Co-rich and Co-free materials. Finally, we revealed that an unequivocal relationship between capacity fade and both dynamic phase stability and surface chemical stability of the cathode with spinel LiMn2O4 as a model system.

Rational composition and morphology designs stabilizing Ni-rich NMC cathodes

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.