Flexible probe for measuring local conductivity variations in Li-ion electrode films

Hardy, Emilee; Clément, D.; Vogel, John E; Wheeler, Dean R.; Mazzeo, Brian A.

doi:10.1063/1.5031536

Cited by 3 publications

(5 citation statements)

References 4 publications

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“…Heterogeneity on such length scales (0.1–0.5 mm) is not commensurate with the microstructural heterogeneity of the LFP particles and suggests the presence of the intrinsic variation in the electrical and ionic conductivity introduced in the composite electrode processing. Indeed, in-plane electrical conductivity heterogeneity has been observed to exist over ∼0.4 mm for much thinner (<100 μm) commercial electrode films . This in-plane heterogeneity could be captured only in the 3D reconstruction applied here, not 1D depth profiling studies.…”

Section: Resultsmentioning

confidence: 92%

Quantifying Reaction and Rate Heterogeneity in Battery Electrodes in 3D through Operando X-ray Diffraction Computed Tomography

Liu

Kazemiabnavi²,

Grenier

et al. 2019

ACS Appl. Mater. Interfaces

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In composite battery electrode architectures, local limitations in ionic and electronic transport can result in nonuniform energy storage reactions. Understanding such reaction heterogeneity is important to optimizing battery performance, including rate capability and mitigating degradation and failure. Here, we use spatially resolved X-ray diffraction computed tomography to map the reaction in a composite electrode based on the LiFePO 4 active material as it undergoes charge and discharge. Accelerated reactions at the electrode faces in contact with either the separator or the current collector demonstrate that both ionic and electronic transport limit the reaction progress. The data quantify how nonuniformity of the electrode reaction leads to variability in the charge/discharge rate, both as a function of time and position within the electrode architecture. Importantly, this local variation in the reaction rate means that the maximum rate that individual cathode particles experience can be substantially higher than the average, control charge/discharge rate, by a factor of at least 2−5 times. This rate heterogeneity may accelerate rate-dependent degradation pathways in regions of the composite electrode experiencing fasterthan-average reaction and has important implications for understanding and optimizing rate-dependent battery performance. Benchmarking multiscale continuum model parameters against the observed reaction heterogeneity permits extension of these models to other electrode geometries.

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Section: Resultsmentioning

confidence: 92%

Quantifying Reaction and Rate Heterogeneity in Battery Electrodes in 3D through Operando X-ray Diffraction Computed Tomography

Liu

Kazemiabnavi²,

Grenier

et al. 2019

ACS Appl. Mater. Interfaces

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“…A key metric for LSB performance is the electronic conductivity of the coating film. 65 A high electronic conductivity improves sulfur utilization due to improved redox kinetics. Therefore, the favorable in plane electronic conductivity of 56 wt % N-NGN (3 h) coating can assist in reactivating these solid and liquid PS during cycling.…”

Section: Resultsmentioning

confidence: 99%

“…A key metric for LSB performance is the electronic conductivity of the coating film . A high electronic conductivity improves sulfur utilization due to improved redox kinetics.…”

Section: Resultsmentioning

confidence: 99%

Multifunctional Effects of Sulfonyl-Anchored, Dual-Doped Multilayered Graphene for High Areal Capacity Lithium Sulfur Batteries

Rana¹,

Luo³

et al. 2019

ACS Cent. Sci.

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Li–S batteries (LSBs) require a minimum 6 mAh cm–2 areal capacity to compete with the state-of-the-art lithium ion batteries (LIBs). However, this areal capacity is difficult to achieve due to a major technical issue—the shuttle effect. Nonpolar carbon materials limit the shuttle effect through physical confinement. However, the polar polysulfides (PSs) only provide weak intermolecular interactions (0.1–0.7 eV) with these nonpolar carbon materials. The physically encapsulated PSs inside the nonpolar carbon scaffold eventually diffuses out and starts shuttling. Chemically interactive hosts are more effective at interacting with the PSs due to high binding energies. Herein, a multifunctional separator coating of nitrogen-doped multilayer graphene (NGN) and −SO3– containing Nafion (N-NGN) is used to mitigate PS shuttling and to produce a high areal capacity LSB. The Nafion is used as a binder instead of PVDF to provide an additional advantage of −SO3– to chemically bind the PS. The motive of this research is to investigate the effect of highly electronegative N and −SO3– (N-NGN) in comparison with the −OH, −COOH, and −SO3– groups from a hydroxyl graphene and Nafion composite (N-OHGN) to mitigate PS shuttling in LSBs. The highly conductive doped graphene architecture (N-NGN) provides efficient pathways for both electrons and ions, which accelerates the electrochemical conversion at high sulfur loading. Moreover, the electron-rich pyridine N and −SO3– show strong chemical affinity with the PS through polar–polar interactions, which is proven by the superior electrochemical performance and density functional theory calculations. Further, the N-NGN (5 h) produces a maximum areal capacity of 12.0 and 11.0 mAh cm–2, respectively, at 15 and 12 mg cm–2 sulfur loading. This areal capacity limit is significantly higher than the required areal capacity of LSBs for commercial application, which shows the significant strength of N-NGN as an excellent separator coating for LSBs.

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“…Flexible 4-four-line probes reported by Wheeler et al [146] have been used to measure in homogeneities in electrode conductivity at the sub mm scale, Fig. 12c.…”

Section: Four-point Probe Conductivitymentioning

confidence: 99%

“…However, these probes inherently measured the in-plane resistance and without further detailed measurements into depth profiling of electrodes these methods cannot provide a complete picture of electrode conductivity. It has also been demonstrated that the addition of electrolyte to the composite electrode decreased the electrical conductivity, bringing further concerns to electrical conductivity measurements performed outside of the cell environment [146,147]. In addition due to the relative thickness and the tortuous nature of electrical conductivity networks in battery electrodes only a small proportion of its surface structure will contribute to the resistivity, potentially neglecting structural gradients.…”

Section: Four-point Probe Conductivitymentioning

confidence: 99%

Carbon binder domain networks and electrical conductivity in lithium-ion battery electrodes: A critical review

Entwistle

Pardikar

et al. 2022

Renewable and Sustainable Energy Reviews

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Flexible probe for measuring local conductivity variations in Li-ion electrode films

Cited by 3 publications

References 4 publications

Quantifying Reaction and Rate Heterogeneity in Battery Electrodes in 3D through Operando X-ray Diffraction Computed Tomography

Quantifying Reaction and Rate Heterogeneity in Battery Electrodes in 3D through Operando X-ray Diffraction Computed Tomography

Multifunctional Effects of Sulfonyl-Anchored, Dual-Doped Multilayered Graphene for High Areal Capacity Lithium Sulfur Batteries

Carbon binder domain networks and electrical conductivity in lithium-ion battery electrodes: A critical review

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