Open AccessUsing Lithium-ion Differential Thermal Analysis to Probe Tortuosity of Negative Electrodes in Lithium-Ion Cells
Author(s) -
Michael Bauer,
J. R. Dahn
Publication year - 2021
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/abdde4
Subject(s) - electrode , electrolyte , tortuosity , lithium (medication) , ion , analytical chemistry (journal) , chemistry , materials science , composite material , chromatography , medicine , organic chemistry , porosity , endocrinology
If the positive electrode of a lithium-ion cell faces a surface with no opposing negative electrode, Li + ions can plate on the nearest edge of the negative electrode current collector. This poses considerable danger to the battery, and so modern Li-ion cells have a negative electrode that is both wider and longer than the positive electrode. In this work, we present evidence using Li-ion cell differential thermal analysis that this overhang causes the formation of long lived electrolyte concentration gradients after discharge or charge due to the long times needed for the lithium content in the overhang region of the negative electrode to equilibrate with the lithium content in the bulk of the negative electrode. Several cases are shown, as well as a comparison to a commercial cell, and an estimation of the type and magnitude of the electrolyte concentration gradient is given. Finally, it is shown that this phenomenon can be applied to easily distinguish between graphite electrodes with high and low tortuosity using differential thermal analysis.