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Aqueous processing of lithium (ion) battery cathodes based on Ni‐rich layered oxides like LiNi0.83Co0.12Mn0.05O2 (NCM) can reduce costs, increase sustainability, and pave the way for F‐free, e.g., biopolymeric binders, however, the degradation of water‐sensitive Ni‐rich NCM remains a challenge. Besides strategies like NCM coatings and processing additives, customized binders can be performance‐decisive via impacting both, electrode processing aspects (paste viscosity, particle dispersibility, etc.) and chemical interactions with NCM surface, though, a distinction between these two impacting factors is difficult given their mutual influences. For this reason, a bifunctional binder system is chosen in this work, i.e., highly viscous xanthan and low viscous pullulan, both polysaccharides known from the food industry, which realize constant viscosity and processing, finally enabling systematic investigation of binder modifications (here pullulan) with various side groups. In fact, while the rate performance remains constant, suggesting a similar composite network with comparable electronic and ionic conductivities, the modified binders affect the NCM||graphite cycle life, where a higher substitution degree of carboxymethylated pullulan can even compete with N‐methyl‐2‐pyrrolidone/polyvinylidene difluoride state‐of‐the‐art system at conventional upper charge voltage (4.2 V); while at 4.5 V water‐reasoned NCM damages get obvious, as seen by enhanced electrode cross‐talk via transition metal deposition on anode. [ABSTRACT FROM AUTHOR]

LiNixMnyCozO2 (x+y+z=1) is one of the most present and versatile positive active materials for lithium ion batteries due to comparatively high specific capacity and high operating potential. However, NMC materials are prone to various degradation effects including moisture uptake, formation of impurities at the particle surface and transition metal dissolution during charge/discharge cycling and/or at elevated temperatures. Beyond that, cation mixing can lead to phase transformation, oxygen evolution, particle cracking and particle disintegration. Therefore, an alumina coating was applied and optimized as protective interphase on LiNi0.6Mn0.2Co0.2O2 (NMC622) powders, using a specifically in‐house developed RF‐magnetron sputtering technique. The alumina coated NMC622 showed a 13 % improvement in capacity retention after 200 charge/discharge cycles in lab‐scale cells, compared to pristine uncoated NMC622. Using electrochemical impedance spectroscopy, the interfacial/interphasial resistance of pristine and alumina coated NCM622 based electrodes were explored to study the impact of the coating on lithium ion transport. Furthermore, the structural and thermal stability of cyclic aged NMC622 were analyzed via TEM, EELS and TGA. Therein, alumina coated samples demonstrated enhanced thermal stability, less structural degradation, and reduced particle cracking. [ABSTRACT FROM AUTHOR]

The drying of electrodes for lithium-ion batteries is one of the most energy- and cost-intensive process steps in battery production. Laser-based drying processes have emerged as promising candidates for electrode manufacturing due to their direct energy input, spatial homogeneity within the laser spot, and rapid controllability. However, it is unclear to what extent electrode and cell quality are affected by higher heating and drying rates. Hybrid systems as a combination of laser- and convection-based drying were investigated in an experimental study with water-processed LFP cathodes. The manufactured electrodes were compared with purely laser-dried and purely convection-dried samples in terms of drying times and quality characteristics. The electrodes were characterized with regard to physical properties like adhesion and electronic conductivity, as well as electrochemical performance using the rate capability. Regarding adhesion and electronic conductivity, the LFP-based cathodes dried in the hybrid-drying process by laser and convection showed similar quality characteristics compared to conventionally dried cathodes, while, at the same time, significantly reducing the overall drying time. In terms of electrochemical performance, measured by the rate capability, no significant differences were found between the drying technologies used. These findings demonstrate the great potential of laser- and convection-based hybrid drying of LFP cathodes to enhance the electrode-drying process in terms of energy efficiency and operational costs. [ABSTRACT FROM AUTHOR]

In zero-excess lithium metal batteries (ZELMBs), also termed "anode-free" LMBs, Li from the positive electrode is electrodeposited onto a bare current collector instead of the Li metal negative electrode commonly used in LMBs. This enables high theoretical energy density and facile, safe, and low-cost assembly. To tackle coulombic inefficiencies during Li deposition/dissolution, 3D structured current collectors can be used instead of 2D foil materials. This study elucidates the Li deposition behavior in custom-made open-porous Cu micro-foams from nucleation to large scale deposition. For the first time in ZELMBs, surface and sub-surface Li deposits in open-porous 3D materials are compared to deposits on 2D foils using cryogenic focused ion beam scanning electron microscopy (cryo-FIB-SEM). The results highlight that Cu micro-foams can store substantial amounts of dendrite-free Li in their open-porous 3D structure, minimizing detrimental volume changes during Li deposition/dissolution. Electrochemical analyses and simulations reveal that current density distribution over the large surface area of the Cu micro-foams reduces the Li nucleation overvoltage by ≈40%. Also, charge/discharge cycling in ZELMBs shows increases in coulombic efficiency, capacity retention, and cycle life. Overall, this work explains how open-porous Cu micro-foam current collectors improve the Li deposition behavior to boost the cycling characteristics of ZELMBs. [ABSTRACT FROM AUTHOR]

In modern electrode manufacturing for lithium-ion batteries, the drying of the electrode pastes consumes a considerable amount of space and energy. To increase the efficiency of the drying process and reduce the footprint of the drying equipment, a laser-based drying process is investigated. Evaporation rates of up to 318 g m−2 s−1 can be measured, which is orders of magnitude higher than the evaporation rates in conventional furnace drying processes. Optical measurements of the slurry components in the visible and near-infrared spectrum are conducted. Thermal analyses the of laser-dried samples reveal that the commonly used binders carboxymethyl-cellulose (CMC) and styrene–butadiene rubber (SBR) are not affected by the laser drying process within the investigated process window. The results indicated that with the combination of a fast laser drying step and a subsequent convection drying step, high evaporation rates can be achieved while maintaining the integrity and adhesion of the anode. [ABSTRACT FROM AUTHOR]

Drying electrodes is very cost-intensive as it is characterized by high energy and space consumption. Laser drying is considered a promising alternative process due to direct energy input and lower operating costs. However, it is unclear whether the same product and process quality can be achieved with laser drying. Silicon–graphite anodes with different silicon contents were processed using either a high-power diode laser or a convection oven. The laser-drying process was investigated using thermography, and the effect of laser drying on the electrode quality was examined using adhesion and residual moisture measurements. Furthermore, thermogravimetric analysis, SEM images and electrical conductivity were used to analyse the laser- and convection-dried anodes. It was shown that silicon–graphite anodes can also be manufactured using laser drying, with a significant reduction in drying time of over 80%. [ABSTRACT FROM AUTHOR]