Galvanostatic interruption of lithium insertion into magnetite: Evidence of surface layer formation
Magnetite is a known lithium intercalation material, and the loss of active, nanocrystalline magnetite can be inferred from the open-circuit potential relaxation. Specifically, for current interruption after relatively small amounts of lithium insertion, the potential first increases and then decrea...
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Published in | Journal of power sources Vol. 321; no. C; pp. 106 - 111 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
Elsevier B.V
30.07.2016
Elsevier |
Subjects | |
Online Access | Get full text |
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Summary: | Magnetite is a known lithium intercalation material, and the loss of active, nanocrystalline magnetite can be inferred from the open-circuit potential relaxation. Specifically, for current interruption after relatively small amounts of lithium insertion, the potential first increases and then decreases, and the decrease is hypothesized to be due to a formation of a surface layer, which increases the solid-state lithium concentration in the remaining active material. Comparisons of simulation to experiment suggest that the reactions with the electrolyte result in the formation of a thin layer of electrochemically inactive material, which is best described by a nucleation and growth mechanism. Simulations are consistent with experimental results observed for 6, 8 and 32-nm crystals. Furthermore, simulations capture the experimental differences in lithiation behavior between the first and second cycles.
•Surface layer formation on magnetite nanocrystals was investigated.•Surface layer formation decreases the amount of active material.•The decrease in active material is proportional to crystal surface area.•The surface layer forms through a nucleation and growth process.•Optimal crystal size balances active material loss and mass transport resistance. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 USDOE Office of Science (SC), Basic Energy Sciences (BES) BNL-112126-2016-JA SC0012704; SC0012673; C090171 |
ISSN: | 0378-7753 1873-2755 |
DOI: | 10.1016/j.jpowsour.2016.04.117 |