Bulk oxygen release inducing cyclic strain domains in Ni-rich ternary cathode materials

Tong Zhou, Xinrun Yu, Fan Li, Jianwei Zhang, Bowen Liu, Longlong Wang, Yuan Yang, Zhiwei Hu, Jun Ma, Chao Li, Guanglei Cui

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Nickel-rich layered transition metal oxide is limited by the poor structural stability during cycling as cathode materials for next-generation lithium-based automotive batteries. In the past, the poor electrochemical performance was mainly attributed to cracks and formation of rock-salt phase on the particle surface at high potentials. Rarely is the effect of bulk phase structure evolution on properties discussed. Here, we report a bulk oxygen release induced dynamic accumulative electrochemical–mechanical coupling failure mechanism. Domain-like rock salt phases are generated due to the oxygen release and transition metals migration in the bulk region of LiNi0.6Co0.2Mn0.2O2 (NCM622) particles at the first cycle high cutoff voltage. Then, reversible compressive/tensile lattice strain alternately dominate around the domain boundary and accumulate with cycling, leading to capacity fading and becoming the origin of intracrystalline cracks. The results suggest that, in addition to the side effects from the surface, the structural transformation of the bulk plays an important role in the capacity fading. The stabilization of lattice oxygen in bulk region is a feasible solution to suppress the structural transition and the inhomogeneous stress distribution.

Original languageEnglish
Pages (from-to)691-697
Number of pages7
JournalEnergy Storage Materials
Volume55
DOIs
StatePublished - Jan 2023
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2022 Elsevier B.V.

Keywords

  • Bulk oxygen release
  • Intracrystalline crack
  • NCM622
  • STEM
  • Strain domain

Fingerprint

Dive into the research topics of 'Bulk oxygen release inducing cyclic strain domains in Ni-rich ternary cathode materials'. Together they form a unique fingerprint.

Cite this