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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. [ABSTRACT FROM AUTHOR]

The drying of solvent‐processed electrodes is a critical process step in the manufacturing of lithium‐ion batteries. The technology used to introduce the energy required for drying into the material, combined with the specified process parameters, significantly influences the resulting electrode properties. A major challenge is to counteract binder migration effects that may occur during drying of the porous electrode structure, causing a decrease in adhesion and electrochemical performance, especially for high drying rates. From this motivation, investigations on the influence of process design during near‐infrared drying of aqueous‐processed graphite anodes are carried out. A multistage drying design with varying parameters in specific drying sections with energy input by radiation is applied. The results show that the specific application of a three‐stage drying profile in combination with energy input by radiation enables a significant decrease in drying time by at least 60% while the electrode properties can be preserved. These findings indicate a beneficial development of binder distribution as a consequence of multistage NIR drying, evidenced by adhesion and electrochemical performance. Finally, the application of the multistage drying profile is theoretically transferred to an industrial‐scale roll‐to‐roll dryer, whereby the necessary dryer length can be reduced by 53%. [ABSTRACT FROM AUTHOR]

Fuel cells used for transport applications hold polymer membranes as a key element. Their efficiency can be significantly increased if structured ion channels are implemented at the molecular level into the proton‐conducting membrane. New functional molecules with selective affinity for ionomers are needed to obtain such a membrane design. This study presents a method to screen for selective peptide binders to perfluorinated sulfonic acid ionomers, e.g., Nafion using ultra‐high density peptide arrays with a spot size of up to 30 µm. First, the ionomer dispersion is incubated with the peptide chip containing 56014 randomly chosen 6‐mer peptides. Afterward, the peptide chip is washed. The peptide WIWHCW with the helix structure is identified as a selective binder to Nafion. The invariant amino acids responsible for binding are also determined using a peptide chip approach. The specific binding pocket of WIWHCW is formed by histidine and tryptophan. Its dissociation constant to the ionomer is measured at ≈140 µM. [ABSTRACT FROM AUTHOR]

In the production of catalyst‐coated membranes (CCMs) for proton‐exchange membrane fuel cells and electrolyzers, the ink formulation and its processing are key factors in determining the resulting catalyst layer. Catalyst inks often contain a multicomponent solvent mixture. Selective drying, which can occur with solvent mixtures, changes the composition in the solidifying film and thus influences the microstructure of the layer that forms. The selectivity depends on the material‐specific thermodynamics of the solvents and the process‐related drying parameters. Different 1‐propanol/water mixtures serve as the state of the art material system considered and commonly used for CCM inks. Typical solvent mixtures can be dried selectively or non‐selectively, depending on the initial ink composition and humidity of the drying air. In mixtures that contain more 1‐propanol than the azeotropic or arheotropic composition, the 1‐propanol content accumulates in the remaining liquid; if there is less, it decreases. Increasing the preloading of the drying air with water leads to a relative water enrichment and shifts the tipping point to higher initial alcohol fractions. This behavior can be transferred to the real CCM production. [ABSTRACT FROM AUTHOR]

Sodium‐ion batteries are becoming an increasingly important complement to lithium‐ion batteries. However, while extensive knowledge on the preparation of Li‐ion batteries with excellent cycling behavior exists, studies on applicable long‐lasting sodium‐ion batteries are still limited. Therefore, this study focuses on the cycling stability of batteries composed of Na3V2(PO4)3/C based cathodes and hard carbon anodes. It is shown that full‐cells with a decent stability are obtained for ethylene carbonate/propylene carbonate electrolyte and the conducting salt NaPF6. With cathode loadings of 1.2 mAh/cm2, after cell formation discharge capacities up to 92.6 mAh/g are obtained, and capacity retentions >90 % over 1000 charge/discharge cycles at 0.5 C/0.5 C are observed. It is shown that both, the additive fluoroethylene carbonate and impurities in the electrolyte, negatively affect the overall discharge capacity and cycling stability and should therefore be avoided. Remarkably, the internal resistances of well‐balanced and well‐built cells did not increase over 1500 cycles and 5 months of testing, which is a very promising result regarding the possible lifespan of the cells. The initial loss of active sodium ions in hard carbon remains a major problem, which can only be partially reduced by proper balancing. [ABSTRACT FROM AUTHOR]

Nanoparticles have many advantages as active materials, such as a short diffusion length, low charge transfer resistance, or a reduced probability of cracking. However, their low packing density makes them unsuitable for commercial battery applications. Hierarchically structured microparticles are synthesized from nanoscale primary particles by targeted aggregation. Due to their open accessible porosity, they retain the advantages of nanomaterials but can be packed much more densely. However, the intrinsic porosity of the secondary particles leads to limitations in processing properties and increases the overall porosity of the electrode, which must be balanced against the improved rate stability and increased lifetime. This is demonstrated for an established cathode material for lithium-ion batteries (LiNi0.33Co0.33Mn0.33O2, NCM111). For active materials with low electrical or ionic conductivity, especially post-lithium systems, hierarchically structured particles are often the only way to produce competitive electrodes. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Sodium‐ion batteries are considered to be one of the most promising postlithium batteries on the verge of commercialization. The electrode processing is expected to be similar to lithium‐ion batteries. However, the producibility and material processing challenges of potential electrode materials for anodes and cathodes are poorly understood. For industrial electrode production, a deep understanding of the processing of electrode materials with different particle morphologies is of great importance. In particular, the correlation between the process conditions and the electrode properties needs to be investigated further to understand the complex interactions between the battery slurry materials, the binder system, the drying process, and the microstructure formation. One promising anode material is hard carbon. The water‐based processing of hard carbon slurries presented in this article shows that the drying behavior is strongly interconnected with the particle size and particle interactions in the drying electrode. This study shows that all the hard carbons investigated do not exhibit binder migration at moderate drying rates. Even at very high drying rates (9 g m−2 s−1, 12 s drying time), an increase in adhesion force of up to 39% is observed for comparatively smaller particles compared to the adhesion force at lower drying rate. [ABSTRACT FROM AUTHOR]

Abstract Large-scale secondary lithium-ion batteries could be a key technology to compensate for the inconsistent energy supply of renewable sources. However, their manufacture is still very costly. In particular, the [...]

Abstract In the field of organic and printed electronics (e.g., polymer solar cells, OLEDs, or Li-ion batteries), there is a growing demand for thin functional layers with highly homogeneous surface [...]

Abstract For optimizing the drying process of thin functional films, knowledge of the relevant influencing parameters is needed. One paramount parameter for design of experimental conditions and the accurate interpretation [...]

Abstract Slot die coating is a film casting process with a highly diverse variety of everyday applications. As a pre-metered process it not only guarantees excellent film uniformity, but is [...]

The selection of an appropriate cathode active material is important for operation performance and production of high‐performance lithium‐ion batteries. Promising candidates are nickel‐rich layered oxides like LiNixCoyMnzO2 (NCM, x+y+z=1) with nickel contents of 'x' ≥ 0.8, characterized by high electrode potential and specific capacity. However, these materials are associated with capacity fading due to their high sensitivity to moisture. Herein, two different polycrystalline NCM materials with nickel contents of 0.81 ≤ 'x' ≤ 0.83 and protective surface coatings are processed in dry‐room atmosphere (dew point of supply air TD ≈ −65 °C) at lab scale including the slurry preparation and coating procedure. In comparison, cathodes are produced in ambient atmosphere and both variants are tested in coin cells. Moreover, processing at pilot scale in ambient atmosphere is realized successfully by continuous coating and drying of the cathodes. Relevant electrode properties such as adhesion strength, specific electrical resistance, and pore‐size distribution for the individual process steps are determined, as well as the moisture uptake during calendering. Furthermore, rate capability and cycling stability are investigated in pouch cells, wherein initial specific discharge capacities of up to 190 mAh g−1 (with regard to the cathode material mass) are achieved at 0.2C. [ABSTRACT FROM AUTHOR]

Lithium‐ion batteries are state‐of‐the‐art and still their performance is subject to constant improvement. These enhancements are based, among other things, on optimization in the electrode production process chain. High optimization potential exists for the drying process of electrodes, as aiming for high drying speeds can greatly reduce both, investment costs and operating costs of the drying. However, high drying rates without appropriate precautions go hand in hand with poorer cell performance and adhesive strength, leading to a conflict between the required performance and production costs of the electrodes. Herein, a numerical approach based on the discrete element method to describe the formation of the electrode structure during drying is presented. The focus is placed on the active material structure and the effects due to particle interactions. Herein, a direct numerical description of the fluid phase is avoided by using various fluid substitute models, so that the simulation time and the computational costs can be greatly reduced. The model is validated by simulating different electrode areal loadings and comparing the achieved layer thicknesses to experimental results of the electrode drying process. A high agreement between experiment and simulation regarding density is obtained for different areal loadings. [ABSTRACT FROM AUTHOR]

Moisture management and postdrying are crucial for Li‐ion battery lifetime and performance as well as overall energy efficiency of electrode production. An optimization of these processes by a fundamental comprehension of sorption and mass transport mechanisms in the electrode holds potential to increase sustainability of this technology. The composition of electrodes determines which of these mechanisms govern the interaction of electrodes with water from atmosphere. In this study, the influence of the binder system, temperature, and pressure of Li‐ion battery anodes on postdrying is focused on. Anodes with the binder system carboxymethylcellulose (CMC)/styrene–butadiene–rubber (SBR) and polyvinylidene fluoride represent a mostly absorbing and mostly adsorbing material system, respectively. Variation of the process parameters temperature and pressure reveals that both material systems show a similar impact of pressure on water mass transport in the electrode during water removal, although a reduced pressure impact for the CMC/SBR system is expected, since in this case most water is absorbed into the polymers and should diffuse independently of the system pressure. Temperature affects water mass transport in the absorbing material system stronger than in the adsorbing material system, due to the strong temperature dependency of the water diffusion inside the absorbing polymers. [ABSTRACT FROM AUTHOR]

Lithium‐ion batteries are used in a wide range of applications, with the electromobility sector being the main contributor to the increasing demand predicted for the next decade. Although batteries play an important role in decarbonizing the transportation sector, their production includes energy‐intensive processes that hinder a more sustainable production. Moreover, the production processes are characterized by a manifold of parameters leading to complex cause–effect relations along the process chain which influences the battery cell quality. Therefore, a sustainable future for battery production and the electromobility sector depends on the environmentally and economically efficient production of high‐performance batteries. Against this background, this work presents a digitalization platform based on the coupling of mechanistic models to digitally reproduce the battery cell production and provide a deeper understanding of the interdependencies on the process, production, and product levels. In addition to a description of the individual models contained in the platform, this work demonstrates their coupling on a use case to study the effects of different solids contents of the coating suspension. Besides providing a multilevel assessment of the parameter interdependencies, considering quality, environmental and economic aspects, the presented framework contributes to knowledge‐based decision support and improvement of production and battery cell performance. [ABSTRACT FROM AUTHOR]

The drying of electrodes represents a critical process step in the production of lithium‐ion batteries. In this process step, unfavorably adjusted drying conditions can result in deteriorated electrode properties. Furthermore, the process speed is restricted by limited heat and mass transfer in purely convective drying. To counteract those effects, energy input by near‐infrared (NIR) radiation is a promising approach. Herein, analytical considerations are carried out to demonstrate the suitability of infrared radiation with regard to achievable electrode temperatures and drying rates. In an experimental approach, aqueous processed graphite anodes are dried with an NIR module, varying the power and the amount of convection for different experiments. The temperature profiles of the electrodes and the drying rates are measured and analyzed, and the electrodes are subsequently characterized using adhesion measurements. The results obtained show that energy input by NIR radiation during the drying of electrodes can lead to an increased drying speed, electrode temperature during drying, and adhesion force of the dry electrode. These findings indicate that the binder distribution during NIR drying is advantageous in terms of electrode adhesion, compared with convectively dried electrodes produced at comparable drying rates, positioning the process promisingly with regard to high throughput rates. [ABSTRACT FROM AUTHOR]