Capturing the Current-Overpotential Nonlinearity of Lithium-Ion Batteries by Nonlinear Electrochemical Impedance Spectroscopy (NLEIS) in Charge and Discharge Direction

Ernst, S.; Heins, Tom Patrick; Schlüter, Nicolas; Schröder, Uwe

doi:10.3389/fenrg.2019.00151

Cited by 22 publications

(19 citation statements)

References 38 publications

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“…19 Thus, the combination of increased resistivity due to high binder content in the cathode matrix, and reduced ionic conductivity from the thicker SPE coating were presumed to increase the ohmic overpotential of the batteries. 71 It should be noted that the thicker SPE coating was selected in this study to facilitate the proposed 3D printing process so that an intact SPE coating was still obtained within the 3D printed composite samples as shown above. It is believed that further development in the composition and thickness of a new ion conductive SPE coating would help achieve enhanced electrochemical performance for the proposed 3D printing method.…”

Section: Resultsmentioning

confidence: 99%

Effects of cathode doping on 3D printed continuous carbon fiber structural battery composites by UV-assisted coextrusion deposition

Pappas

Thakur

Dong

2021

Journal of Composite Materials

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Structural battery composites are capable of significant system level mass and volume reductions not possible with separate battery and structural components by simultaneously carrying mechanical loads and storing electrical energy. The ability to 3D print lithium-ion structural batteries in arbitrary geometries would not only allow a flexible battery design but also facilitate its implementation as a structural component. This study presents a new 3D carbon fiber structural battery composite 3D printed by an ultraviolet (UV)-assisted coextrusion deposition method. With individual carbon fibers coated by solid polymer electrolyte (SPE) and dispersed within cathode doped matrix, energy storage is achieved in micro-battery cells at the fiber level within the 3D printed structural battery composite. The 3D printed structural battery composites with various complex geometries are demonstrated by successfully powering up LEDs. The SPE coating and cathode doping effect on microstructure, printability, mechanical and electrochemical properties are further characterized and investigated. A trade-off between printability and electrochemical performance is observed due to hindered curing by the doped cathode materials. The obtained electrochemical and mechanical performance is comparable to the carbon fiber based structural battery composites fabricated by conventional lay-up processes. These well demonstrate the great potentials of the proposed 3D printing method in rapidly fabricating functional structural battery composite components with complex geometries.

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Section: Resultsmentioning

confidence: 99%

Effects of cathode doping on 3D printed continuous carbon fiber structural battery composites by UV-assisted coextrusion deposition

Pappas

Thakur

Dong

2021

Journal of Composite Materials

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“…They can be used, for instance, to differentiate different physicochemical processes within impedance spectra like diffusion and charge transfer processes. [81,90,96] Whilst in classical EIS studies nonlinearities result in the unwanted distortion of the measurement results, NL approaches make direct use of the additional effects that occur. This way, they gain a higher information level about the investigated system.…”

Section: Nonlinear Electrochemical Methodsmentioning

confidence: 99%

“…One way to counteract this effect is to switch the DC signal between the charge and discharge direction for each NL measurement. [81] However, windowing of the resulting signal still stays mandatory to prevent the aliasing effect and to perform a drift correction also on the data level. [81] Both approaches have different advantages and downsides.…”

Section: Nonlinear Electrochemical Methodsmentioning

confidence: 99%

“…[81] However, windowing of the resulting signal still stays mandatory to prevent the aliasing effect and to perform a drift correction also on the data level. [81] Both approaches have different advantages and downsides. The usage of high-amplitude signals is usually easy to perform and the dependence of the response signal from the input signal can be well controlled.…”

Section: Nonlinear Electrochemical Methodsmentioning

confidence: 99%

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Nonlinear Electrochemical Analysis: Worth the Effort to Reveal New Insights into Energy Materials

Schlüter

Novák

Schröder

2022

Advanced Energy Materials

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and the effectiveness and durability of the materials applied, researchers always call for reliable and detailed knowledge of the mechanism(s) of both, main and side reactions, and especially for their kinetics. In order to gain the relevant information, a large number of methods have been proposed to characterize battery materials, battery electrodes and their interfaces, and battery cells. But when samples are taken out of the cells and analyzed later, there is a high risk of both, contamination and changes due to possible relaxation processes, and the challenge is to draw sound conclusions in respect to a "living and breathing" battery cell, i.e., to a cell under current flow (cf. Figure 1). Therefore, the so-called in situ and operando (and often online) methods are preferred. Sometimes they are the only option to collect relevant data to understand and improve materials for energy systems. [5] In many cases, results from different techniques need to be combined to obtain sound conclusions. [6,7] The terminology for the aforementioned methods shifted during the last decade and is not always consistent throughout the literature. Nowadays, the general understanding is as follows: An operando experiment means a characterization experiment in an electrochemical cell (e.g., battery, fuel cell, electrolyzer) under current flow, with either the potential or the current controlled. One of the many examples is the operando neutron powder diffraction, a technique analyzing the changes in the structure of battery materials in "real" battery cells under current flow with the help of neutron diffraction. [9] Another example is the operando X-ray photoelectron spectroscopy experiment (normally limited to vacuum-compatible cells with nonvolatile electrolytes) providing information about the changes of the chemical composition of the interfacial species with the potential. [10,11] An in situ experiment is also an experiment in a battery cell, however, the current flow is interrupted when the data are collected. An example here is the in situ X-ray absorption spectroscopy (XAS) experiment in which the cell has to be disconnected for technical reasons during the operation of the detector [7] or the tomography of energy materials by means of neutron or X-ray source. [12,13] Online techniques are understood here as either continuously or periodically analyzed samples that are taken out of the electrochemical cell. A typical example is the online (differential) electrochemical mass spectrometry (often shortened as online electrochemical mass spectrometry (OEMS)/differential electrochemical mass spectrometry (DEMS)) analyzing the volatile products of electrochemical reactions with the help of a mass spectrometer by

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“…Higher resistance leads a cell to reach the discharge cutoff voltage limit earlier and makes the available discharge capacity lower [40]. Moreover, the relationship between resistance and current flow indicates that the charge transfer overpotential is one of the determinative parameters in electrochemical kinetics as it expresses the resistance reflection to the electrode surface reaction [42].…”

Section: Resistance Evaluation Trendmentioning

confidence: 99%

Investigation on Cycling and Calendar Aging Processes of 3.4 Ah Lithium-Sulfur Pouch Cells

2021

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Much attention has been paid to rechargeable lithium-sulfur batteries (Li–SBs) due to their high theoretical specific capacity, high theoretical energy density, and affordable cost. However, their rapid c fading capacity has been one of the key defects in their commercialization. It is believed that sulfuric cathode degradation is driven mainly by passivation of the cathode surface by Li2S at discharge, polysulfide shuttle (reducing the amount of active sulfur at the cathode, passivation of anode surface), and volume changes in the sulfuric cathode. These degradation mechanisms are significant during cycling, and the polysulfide shuttle is strongly present during storage at a high state-of-charge (SOC). Thus, storage at 50% SOC is used to evaluate the effect of the remaining degradation processes on the cell’s performance. In this work, unlike most of the other previous observations that were performed at small-scale cells (coin cells), 3.4 Ah pouch Li–SBs were tested using cycling and calendar aging protocols, and their performance indicators were analyzed. As expected, the fade capacity of the cycling aging cells was greater than that of the calendar aging cells. Additionally, the measurements for the calendar aging cells indicate that, contrary to the expectation of stopping the solubility of long-chain polysulfides and not attending the shuttle effect, these phenomena occur continuously under open-circuit conditions.

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Capturing the Current-Overpotential Nonlinearity of Lithium-Ion Batteries by Nonlinear Electrochemical Impedance Spectroscopy (NLEIS) in Charge and Discharge Direction

Cited by 22 publications

References 38 publications

Effects of cathode doping on 3D printed continuous carbon fiber structural battery composites by UV-assisted coextrusion deposition

Effects of cathode doping on 3D printed continuous carbon fiber structural battery composites by UV-assisted coextrusion deposition

Nonlinear Electrochemical Analysis: Worth the Effort to Reveal New Insights into Energy Materials

Investigation on Cycling and Calendar Aging Processes of 3.4 Ah Lithium-Sulfur Pouch Cells

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