Optimization of Edge Quality in the Slot‐Die Coating Process of High‐Capacity Lithium‐Ion Battery Electrodes

Spiegel, Sandro; Hoffmann, Alexander; Klemens, Julian; Scharfer, Philip; Schabel, Wilhelm

doi:10.1002/ente.202200684

Cited by 8 publications

(7 citation statements)

References 29 publications

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“…It should be noted that a high viscosity at low shear rates is advantageous, as this limits particle movement (less susceptible to sedimentation). Towards higher shear rates (>10 s −1 ) the viscosity of the anode and the viscosity of the cathode slurries approach each other indicating a comparable suitability for slot‐die coating [10,33,58] . A further effect is that scrap rates due to edge elevations during electrode manufacturing can be minimized by slurries with a higher viscosity at low shear rates and shear thinning behavior [33,58–60] …”

Section: Resultsmentioning

confidence: 99%

“…Towards higher shear rates (> 10 s À 1 ) the viscosity of the anode and the viscosity of the cathode slurries approach each other indicating a comparable suitability for slot-die coating. [10,33,58] A further effect is that scrap rates due to edge elevations during electrode manufacturing can be minimized by slurries with a higher viscosity at low shear rates and shear thinning behavior. [33,[58][59][60] As suggested in the previous section, the different drying times may be compensated by increasing the solid content for SIB materials with a lower capacity than LIB materials.…”

Section: Hc Lfp Pbamentioning

confidence: 99%

“…[10,33,58] A further effect is that scrap rates due to edge elevations during electrode manufacturing can be minimized by slurries with a higher viscosity at low shear rates and shear thinning behavior. [33,[58][59][60] As suggested in the previous section, the different drying times may be compensated by increasing the solid content for SIB materials with a lower capacity than LIB materials. However, it can be seen from the determination of viscosity that an increase in solid content, with otherwise the same composition between LIB and SIB, leads to a further increase in viscosity.…”

Section: Hc Lfp Pbamentioning

confidence: 99%

See 2 more Smart Citations

Challenges and Opportunities for Large‐Scale Electrode Processing for Sodium‐Ion and Lithium‐Ion Battery

Klemens,

Wurba,

Burger

et al. 2023

Batteries & Supercaps

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Sodium‐ion batteries are an emerging technology that is still at an early stage of development. The electrode processing for anode and cathode is expected to be similar to lithium‐ion batteries (drop‐in technology), yet a detailed comparison is not published. There are ongoing questions about the influence of the active materials on processing parameters such as slurry viscosity, coating thicknesses, drying times, and behavior during fast drying. Herein, the expected drying time for the same areal capacity of anodes (graphite vs. hard carbon) and cathodes (lithium iron phosphate vs. Prussian blue analogs) are compared based on respective specific capacities reported in the literature. Estimates are made for the materials’ impact on production speed or dryer length. Within the experimental part, water‐based slurries of the same composition are mixed using different active materials according to identical procedure and the viscosity is compared. When drying at a constant drying rate (0.75 g m−2 s−1), lithium iron phosphate electrodes with different areal capacities (1–3 mAh cm−2) are shown to have the highest adhesion. For high drying rates (3 g m−2 s−1) at constant areal capacity, especially the investigated electrodes based on hard carbon show that no binder migration occurs.

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Section: Resultsmentioning

confidence: 99%

Section: Hc Lfp Pbamentioning

confidence: 99%

Section: Hc Lfp Pbamentioning

confidence: 99%

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Challenges and Opportunities for Large‐Scale Electrode Processing for Sodium‐Ion and Lithium‐Ion Battery

Klemens,

Wurba,

Burger

et al. 2023

Batteries & Supercaps

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“…[36] This reduces the reject rate during electrode production. [37][38][39] Since the same solid content and the same electrode composition with the same CMC amount was adjusted, all three HC slurries for SIB and the graphite slurry for LIB show the same behavior for the viscosity at a shear rate above 100 s À1 . In the slot-die-coating process at state-of-the-art industrial coating speeds, typical shear rates in the coating gap are above 400 s À1 .…”

Section: Slurry Flow Behaviormentioning

confidence: 99%

“…In the slot-die-coating process at state-of-the-art industrial coating speeds, typical shear rates in the coating gap are above 400 s À1 . [37,40] It is assumed that the processability, in particular toward faster industrial coating speeds, will be similar for all investigated slurries and the coating equipment for LIB anodes at pilot and industrial coating plants can be used for HC slurries for SIB without major changes or investments.…”

Section: Slurry Flow Behaviormentioning

confidence: 99%

Process and Drying Behavior Toward Higher Drying Rates of Hard Carbon Anodes for Sodium‐Ion Batteries with Different Particle Sizes: An Experimental Study in Comparison to Graphite for Lithium‐Ion‐Batteries

et al. 2023

Self Cite

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Lithium-ion batteries (LIB) and sodium-ion batteries (SIB) are both based on similar intercalation/insertion electrodes of the respective alkali ions into the active materials during charging and discharging. [1] Due to the larger and heavier sodium (Na) ion, a lower gravimetric and as well volumetric capacity than with lithium can be achieved. [2,3] However, given the resource availability of active materials from sustainable raw materials, at potentially low cost, SIB is one of the most promising post-Li batteries for widespread commercialization in the coming years. [4][5][6] Electrode processing of materials for SIB is expected to be very similar to the processing of LIB materials. However, the producibility and material processing challenges of potential electrode materials for anodes and cathodes are poorly investigated.Unlike for the LIB, graphite cannot be recommended as anode material for the SIB, because the formation of a Na-graphite-intercalation compound is energetically unfavorable and has a very low capacity. [7][8][9][10] Instead, hard carbon (HC) is considered to be a promising anode active material with good electrochemical performance for alkali-metal-ion batteries, such as SIBs. [8] The low material costs, the fact that HC can be produced from sustainable raw materials, and the low electrode potential are advantageous for the use of HC as an anode material for SIB. [11,12] However, high capacity losses in the first cycles and at high current rates are still challenging. The performance characteristics of HC active materials, which result from different synthesis methods, are different. [8] The selected precursor and the carbonization conditions, namely, the carbonization temperature, influence the nongraphitic structure of the HC produced and thus, its properties. [2,8,10] The non graphitic structure of the HC offers various areas where Na ions can be deposited. These include especially the regions between the graphite-like domains consisting of micropores and defect sites. Various models describing the storage mechanism, which are controversially discussed, can be found in the literature. [2,10,13,14]

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Additive Influence on Binder Migration in Electrode Drying

Burger,

Klemens,

Keim

et al. 2024

Energy Tech

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Two main goals for the industrial, slurry‐based electrode processing are a high process speed and the maximum possible material efficiency. This makes an increased drying rate and active material share favorable, but both are limited by adverse effects on the electrode quality. The adverse effects of fast drying are associated with the migration of binder. In this article, the slurry properties of water‐based graphite slurries are manipulated using a synthetic, layered silicate as additive. The influence of the polymer‐particle composite network on the viscosity, adhesion strength, and cell performance is investigated. By addition of a small amount of additive (0.5 wt% of the dry electrode), the binder migration is mitigated up to a drying rate of 6 g m−2 s−1 for graphite anodes with ≈4.2 mAh cm−2 (corresponding with 30 s drying time) leading to a possible increase of eight times the process speed compared to drying with 0.75 g m−2 s−1 if adverse effects on the tortuosity of the electrodes can be solved. In this work, a combination of additive usage is pointed out with a multilayer approach and first insights are provided in how the binder migration may be mitigated to gain structurally optimized fast‐dried electrodes without losses in electrode quality.

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Optimization of Edge Quality in the Slot‐Die Coating Process of High‐Capacity Lithium‐Ion Battery Electrodes

Cited by 8 publications

References 29 publications

Challenges and Opportunities for Large‐Scale Electrode Processing for Sodium‐Ion and Lithium‐Ion Battery

Challenges and Opportunities for Large‐Scale Electrode Processing for Sodium‐Ion and Lithium‐Ion Battery

Process and Drying Behavior Toward Higher Drying Rates of Hard Carbon Anodes for Sodium‐Ion Batteries with Different Particle Sizes: An Experimental Study in Comparison to Graphite for Lithium‐Ion‐Batteries

Additive Influence on Binder Migration in Electrode Drying

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