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Three‐Phase Reconstruction Reveals How the Microscopic Structure of the Carbon‐Binder Domain Affects Ion Transport in Lithium‐Ion Batteries
Author(s) -
Kroll Moritz,
Karstens Sarah L.,
Cronau Marvin,
Höltzel Alexandra,
Schlabach Sabine,
Nobel Nikita,
Redenbach Claudia,
Roling Bernhard,
Tallarek Ulrich
Publication year - 2021
Publication title -
batteries and supercaps
Language(s) - English
Resource type - Journals
ISSN - 2566-6223
DOI - 10.1002/batt.202100057
Subject(s) - tortuosity , materials science , lithium (medication) , ion , diffusion , phase (matter) , dielectric spectroscopy , electrolyte , ionic bonding , scanning electron microscope , analytical chemistry (journal) , porosity , electrochemistry , chemistry , composite material , physics , thermodynamics , electrode , medicine , organic chemistry , chromatography , endocrinology
The morphology of the electrolyte‐filled pore space in lithium‐ion batteries is determined by the solid microstructure formed by μm‐sized active material particles and the smaller‐featured carbon binder domain (CBD). Tomographic reconstructions have largely neglected the CBD, resulting in inadequately defined pore space morphologies at odds with experimental ionic tortuosity values. We present a three‐phase reconstruction of a LiCoO 2 composite cathode by focused ion‐beam scanning electron microscopy tomography. Morphological analysis proves that the reconstruction, which combines an unprecedented volume (20 μm minimum edge length) with the hitherto highest resolution (13.9×13.9×20 nm 3 voxel size), represents the cathode's pore space morphology. Pore‐scale diffusion simulations show consideration of the resolved CBD as indispensable to reproduce ionic tortuosity values from electrochemical impedance spectroscopy. Our results reveal the CBD as a convoluted network that dominates the pore space morphology and limits Li + transport through tortuous and constricted diffusion pathways.