Design of Battery Electrodes with Dual‐Scale Porosity to Minimize Tortuosity and Maximize Performance

Bae, Chang Jun; Erdonmez, Can K.; Halloran, John W.; Chiang, Yet Ming

doi:10.1002/adma.201204055

Cited by 271 publications

(239 citation statements)

References 25 publications

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“…Consequently, it is necessary to design thick electrode architectures to take advantage of the increased energy density provided by the higher active material volume ratio, while minimizing the tortuosity and transport limitations that can be detrimental to power performance. Many different designs have been suggested, including graded-porosity and hierarchical architectures, 67,[72][73][74][75][76] and several simulations have shown that smaller active material particles can help decrease the polarization and capacity loss observed at high discharge rates by shortening the Li-ion diffusion path in the particles. 68,71,77 Yet, particle size variations also affect the packing structure of the electrode and can result in different pore sizes and distributions, as well as in differences in the contact resistance between the electrode and the current collector.…”

Section: Electrode Engineeringmentioning

confidence: 99%

“…Another method to reduce tortuosity is through electrode processing. Introducing a pore former that can be well controlled and eliminated during electrode drying or sintering step is one effective method to create straight channels (where tortuosity is 1) in electrodes 72,80 The straight channels can also be created by laser structuring, 81 coextruded electrodes with a low-density area besides a higher density area, 82 or 3D printing interdigitated electrodes. 83 Nevertheless, better understanding on current distribution and its effect on lithium plating is needed for these special structures.…”

Section: Electrode Engineeringmentioning

confidence: 99%

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Toward Low-Cost, High-Energy Density, and High-Power Density Lithium-Ion Batteries

Ruther

et al. 2017

JOM

232

136

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Reducing cost and increasing energy density are two barriers for widespread application of lithium-ion batteries in electric vehicles. Although the cost of electric vehicle batteries has been reduced by $70% from 2008 to 2015, the current battery pack cost ($268/kWh in 2015) is still >2 times what the USABC targets ($125/kWh). Even though many advancements in cell chemistry have been realized since the lithium-ion battery was first commercialized in 1991, few major breakthroughs have occurred in the past decade. Therefore, future cost reduction will rely on cell manufacturing and broader market acceptance. This article discusses three major aspects for cost reduction: (1) quality control to minimize scrap rate in cell manufacturing; (2) novel electrode processing and engineering to reduce processing cost and increase energy density and throughputs; and (3) material development and optimization for lithium-ion batteries with high-energy density. Insights on increasing energy and power densities of lithium-ion batteries are also addressed.

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Section: Electrode Engineeringmentioning

confidence: 99%

Section: Electrode Engineeringmentioning

confidence: 99%

Toward Low-Cost, High-Energy Density, and High-Power Density Lithium-Ion Batteries

Ruther

et al. 2017

JOM

232

136

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“…Bae et al, 91 for example, applied a two pronged approached to improve electrode design: first, using a modified model by Doyle and Newman 92 , the tortuosity of different electrode microstructures with periodically spaced flow channels, was calculated. Based on these results, LiCoO2 electrodes mimicking the modelled microstructures were manufactured using a co-extrusion procedure.…”

Section: Figure 4: Comparison Of Experimentally and Image Based Tortumentioning

confidence: 99%

Tortuosity in electrochemical devices: a review of calculation approaches

Tjaden

Brett

Shearing

2016

International Materials Reviews

211

188

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The tortuosity of a structure plays a vital role in the transport of mass and charge in electrochemical devices. Concentration polarisation losses at high current densities are caused by mass transport limitations and are thus a function of microstructural characteristics. As tortuosity is notoriously difficult to ascertain, a wide and diverse range of methods has been developed to extract the tortuosity of a structure. These methods differ significantly in terms of calculation approach and data preparation techniques. Here, we review tortuosity calculation procedures applied in the field of electrochemical devices to better understand the resulting values presented in the literature. Visible differences between calculation methods are observed, especially when using porosity-tortuosity relationships and when comparing geometric and flux based tortuosity calculation approaches.

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“…13 While the tortuosity of microstructures with monodisperse pores typically increases with increasing total porosity, 15 microstructures with two disparate structural length scales can be used to decrease apparent tortuosity at fixed porosity. 9 Such bi-tortuous electrodes have been studied in the context of Li-ion batteries experimentally 14 and theoretically. 9,16,17,a The orientation of solid particles comprising porous electrodes for energy storage has also been used as a strategy to control tortuosity experimentally, and thereby enhance cycling performance relative to conventionally fabricated electrodes.…”

mentioning

confidence: 99%

“…Aside from its geometric interpretation, tortuosity impacts electrode charging dynamics by way of the effective ionic conductivity κ ef f = κ 0 ε/τ and the effective ionic diffusivity D ef f = D 0 ε/τ, where κ 0 and D 0 are the bulk values of ionic conductivity and diffusivity, and ε is porosity. 8,[11][12][13][14] The reduction of the effective transport property relative to its corresponding bulk value can be captured using the MacMullin number, Mc, from the following definition: κ ef f /κ 0 = 1/Mc = ε/τ. 13 While the tortuosity of microstructures with monodisperse pores typically increases with increasing total porosity, 15 microstructures with two disparate structural length scales can be used to decrease apparent tortuosity at fixed porosity.…”

mentioning

confidence: 99%

Capacitive Performance and Tortuosity of Activated Carbon Electrodes with Macroscopic Pores

Reale

Smith

2018

J. Electrochem. Soc.

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The rate of ionic conduction through the electrolyte of porous electrodes is determined in part by the tortuosity, a factor describing the effective length an ion must travel through the microstructure's pores. To facilitate ionic conduction and adsorption into the electric double-layers of capacitive electrodes, we show that macroscopic pores can be added to reduce the effective tortuosity by providing more direct paths to capacitive interfaces. We show experimental and simulated results of fabricating and testing electrodes that are machined to include macro-pores aligned normal to current collectors. Through the reduction of tortuosity, these "bi-tortuous" electrodes surpass unpatterned electrodes in effective ionic conductivity and capacitance. The degree of improvement is dependent on the electrodes' thickness and charging rate. Potable water demand together with agricultural and industrial needs are likely to drive the desalination of seawater, wastewater, and brackish water resources, and capacitive deionization (CDI) is one potential technology for these purposes.1 In CDI anions and cations are removed from feedwater solution by way of capacitive adsorption into electric double-layers (EDLs). The rate of salt removal in CDI ultimately influences the cost of water production, and, hence, achieving high salt removal rates is critical to making economical CDI devices. Salt removal rate typically increases with the current density used 2 because one electron is transferred for every monovalent ion adsorbed when co-ion adsorption is negligible. Thick electrodes in CDI have the potential to increase areal capacitance and enable the treatment of concentrated salt water, but such electrodes typically suffer from cracking during fabrication, increased ionic resistance, and energy consumption that typically restricts thickness to less than 350 μm.3 While alternative strategies can be used to eliminate these effects (including flow-electrode architectures 4 and intercalation-based electrodes 5-7 ) strategies to simultaneously increase salt removal rate with conventional EDL-based electrodes are desirable.In porous electrodes, including both EDL-and intercalation-based, microstructure is known to influence internal resistance, capacitance, and energy efficiency. In particular, the tortuosity τ of a porous electrode material is the ratio of the microscopic path length that an ion takes within pores normalized by the Cartesian distance between the endpoints of the path. [8][9][10] In general, porous electrodes exhibit tortuosity exceeding unity as a result of the random arrangement of impenetrable solid matrix comprising the electrode. Aside from its geometric interpretation, tortuosity impacts electrode charging dynamics by way of the effective ionic conductivity κ ef f = κ 0 ε/τ and the effective ionic diffusivity D ef f = D 0 ε/τ, where κ 0 and D 0 are the bulk values of ionic conductivity and diffusivity, and ε is porosity. 8,[11][12][13][14] The reduction of the effective transport property relative to its corres...

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Design of Battery Electrodes with Dual‐Scale Porosity to Minimize Tortuosity and Maximize Performance

Cited by 271 publications

References 25 publications

Toward Low-Cost, High-Energy Density, and High-Power Density Lithium-Ion Batteries

Toward Low-Cost, High-Energy Density, and High-Power Density Lithium-Ion Batteries

Tortuosity in electrochemical devices: a review of calculation approaches

Capacitive Performance and Tortuosity of Activated Carbon Electrodes with Macroscopic Pores

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