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Toward Optimal Performance and In‐Depth Understanding of Spinel Li 4 Ti 5 O 12 Electrodes through Phase Field Modeling
Author(s) -
Vasileiadis Alexandros,
de Klerk Niek J. J.,
Smith Raymond B.,
Ganapathy Swapna,
Harks Peter Paul R. M. L.,
Bazant Martin Z.,
Wagemaker Marnix
Publication year - 2018
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201705992
Subject(s) - materials science , spinel , mesoscopic physics , electrode , phase (matter) , ion , nanoscopic scale , chemical physics , nanotechnology , condensed matter physics , chemistry , physics , quantum mechanics , metallurgy
Computational modeling is vital for the fundamental understanding of processes in Li‐ion batteries. However, capturing nanoscopic to mesoscopic phase thermodynamics and kinetics in the solid electrode particles embedded in realistic electrode morphologies is challenging. In particular for electrode materials displaying a first order phase transition, such as LiFePO 4 , graphite, and spinel Li 4 Ti 5 O 12 , predicting the macroscopic electrochemical behavior requires an accurate physical model. Herein, a thermodynamic phase field model is presented for Li‐ion insertion in spinel Li 4 Ti 5 O 12 which captures the performance limitations presented in literature as a function of all relevant electrode parameters. The phase stability in the model is based on ab initio density functional theory calculations and the Li‐ion diffusion parameters on nanoscopic nuclear magnetic resonance (NMR) measurements of Li‐ion mobility, resulting in a parameter free model. The direct comparison with prepared electrodes shows good agreement over three orders of magnitude in the discharge current. Overpotentials associated with the various charge transport processes, as well as the active particle fraction relevant for local hotspots in batteries, are analyzed. It is demonstrated which process limits the electrode performance under a variety of realistic conditions, providing comprehensive understanding of the nanoscopic to microscopic properties. These results provide concrete directions toward the design of optimally performing Li 4 Ti 5 O 12 electrodes.