The kinetics and uniformity of ion insertion reactions at the solid-liquid interface govern the rate capability and lifetime, respectively, of electrochemical devices such as Li-ion batteries. Using an operando x-ray microscopy platform that maps the dynamics of the Li composition and insertion rate in LixFePO4, we found that nanoscale spatial variations in rate and in composition control the lithiation pathway at the subparticle length scale. Specifically, spatial variations in the insertion rate constant lead to the formation of nonuniform domains, and the composition dependence of the rate constant amplifies nonuniformities during delithiation but suppresses them during lithiation, and moreover stabilizes the solid solution during lithiation. This coupling of lithium composition and surface reaction rates controls the kinetics and uniformity during electrochemical ion insertion.
|Original language||English (US)|
|Number of pages||6|
|State||Published - Aug 5 2016|
Bibliographical noteKAUST Repository Item: Exported on 2022-06-08
Acknowledgements: The x-ray component of this work was supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences, Division of Materials Sciences and Engineering (contract DE-AC02-76SF00515). The battery component of this work was supported by the Ford-Stanford Alliance. The Advanced Light Source is supported by the DOE Office of Basic Energy Sciences under contract DE-AC02-05CH11231. N.J.S. and D.H.A. acknowledge support from the DOE Office of Basic Energy Sciences SBIR program under awards DE-SC-0007691 and DE-SC-0009573. Beam line 18.104.22.168 at the Advanced Light Source was funded through a donation by the King Abdullah University of Science and Technology. Also supported by a NSF Graduate Research Fellowship under grant DGE-114747 (Y.L.) and by the Global Climate and Energy Project at Stanford University and the DOE Office of Basic Energy Sciences through the SUNCAT Center for Interface Science and Catalysis (M.Z.B.). N.J.S. and D.H.A. are employed by Hummingbird Scientific, which designed and manufactured the microfluidic liquid cell used in these experiments. Part of this work was conducted the Stanford Nano Shared Facilities and the Stanford Nanofabrication Facility. We thank J. Nelson Weker, A. Wise, H. W. Shiu, M. Farmand, D. Kilcoyne, S. Fakra, Y. S. Hsieh, and A. Kammers for insightful discussions and assistance with the experiment. The raw data for this experiment are available as part of the supplementary materials.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.