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Title: Kinetic phase evolution of spinel cobalt oxide during lithiation

Spinel cobalt oxide has been proposed to undergo a multiple-step reaction during the electrochemical lithiation process. Understanding the kinetics of the lithiation process in this compound is crucial to optimize its performance and cyclability. In this work, we have utilized a low-angle annular dark-field scanning transmission electron microscopy method to visualize the dynamic reaction process in real time and study the reaction kinetics at different rates. We show that the particles undergo a two-step reaction at the single-particle level, which includes an initial intercalation reaction followed by a conversion reaction. At low rates, the conversion reaction starts after the intercalation reaction has fully finished, consistent with the prediction of density functional theoretical calculations. At high rates, the intercalation reaction is overwhelmed by the subsequently nucleated conversion reaction, and the reaction speeds of both the intercalation and conversion reactions are increased. Phase-field simulations show the crucial role of surface diffusion rates of lithium ions in controlling this process. Furthermore, this work provides microscopic insights into the reaction dynamics in non-equilibrium conditions and highlights the effect of lithium diffusion rates on the overall reaction homogeneity as well as the performance.
 [1] ;  [2] ;  [2] ;  [3] ;  [4] ;  [2] ;  [2] ;  [2] ;  [2] ;  [4] ;  [2] ;  [2]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States); Stony Brook Univ., Stony Brook, NY (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)
  3. Harvard Univ., Cambridge, MA (United States)
  4. Univ. of Maryland, College Park, MD (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 1936-0851; KC0403020
Grant/Contract Number:
Accepted Manuscript
Journal Name:
ACS Nano
Additional Journal Information:
Journal Name: ACS Nano; Journal ID: ISSN 1936-0851
American Chemical Society
Research Org:
Brookhaven National Lab. (BNL), Upton, NY (United States). Center for Functional Nanomaterials (CFN)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
29 ENERGY PLANNING, POLICY, AND ECONOMY; Co3O4 nanoparticles; lithium ion battery; in situ TEM; Center for Functional Nanomaterials
OSTI Identifier: