The role of the pH value in water-based pastes on the processing and performance of Ni-rich LiNi0.5Mn0.3Co0.2O2 based positive electrodes

Ibing, Lukas; Gallasch, Tobias; Friesen, Alex; Niehoff, Philip; Hintennach, Andreas; Winter, Martin; Börner, Markus

doi:10.1016/j.jpowsour.2020.228608

Cited by 19 publications

(16 citation statements)

References 38 publications

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“…Making the slurry more basic (i.e., minimizing the proton concentration) could reduce cation exchange, although the current-collector corrosion makes this unrealistic. Combining a carbon-coated current collector with a highly basic NMC532 aqueous slurry (intentionally made through LiOH addition) can simultaneously address corrosion and cation exchange because the carbon coating protects the aluminum from exposure to the basic slurry . Of course, coating long rolls of aluminum with carbon is nontrivial and introduces a processing cost, as even small uncoated sections of sheet could compromise a cell’s performance.…”

Section: Future Electrode and Cell Processingmentioning

confidence: 99%

From Materials to Cell: State-of-the-Art and Prospective Technologies for Lithium-Ion Battery Electrode Processing

et al. 2021

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Electrode processing plays an important role in advancing lithium-ion battery technologies and has a significant impact on cell energy density, manufacturing cost, and throughput. Compared to the extensive research on materials development, however, there has been much less effort in this area. In this Review, we outline each step in the electrode processing of lithium-ion batteries from materials to cell assembly, summarize the recent progress in individual steps, deconvolute the interplays between those steps, discuss the underlying constraints, and share some prospective technologies. This Review aims to provide an overview of the whole process in lithium-ion battery fabrication from powder to cell formation and bridge the gap between academic development and industrial manufacturing.

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Section: Future Electrode and Cell Processingmentioning

confidence: 99%

From Materials to Cell: State-of-the-Art and Prospective Technologies for Lithium-Ion Battery Electrode Processing

et al. 2021

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“…However, only a few groups have studied the effect of pH value on the electrochemical properties of electrodes. Ibing et al [ 35 ] studied the effect of pH values at 12.5 and 7.6 on the electrochemical performance of NMC 532 electrodes, while Bauer et al [ 17 ] reported the performance of aqueous processed NMC 111 electrodes at pH values of 7–11. So far to the best of our knowledge, no related research was established for NMC 622.…”

Section: Introductionmentioning

confidence: 99%

Characterization and Laser Structuring of Aqueous Processed Li(Ni0.6Mn0.2Co0.2)O2 Thick-Film Cathodes for Lithium-Ion Batteries

2021

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Lithium-ion batteries have led the revolution in portable electronic devices and electrical vehicles due to their high gravimetric energy density. In particular, layered cathode material Li(Ni0.6Mn0.2Co0.2)O2 (NMC 622) can deliver high specific capacities of about 180 mAh/g. However, traditional cathode manufacturing involves high processing costs and environmental issues due to the use of organic binder polyvinylidenfluoride (PVDF) and highly toxic solvent N-methyl-pyrrolidone (NMP). In order to overcome these drawbacks, aqueous processing of thick-film NMC 622 cathodes was studied using carboxymethyl cellulose and fluorine acrylic hybrid latex as binders. Acetic acid was added during the mixing process to obtain slurries with pH values varying from 7.4 to 12.1. The electrode films could be produced with high homogeneity using slurries with pH values smaller than 10. Cyclic voltammetry measurements showed that the addition of acetic acid did not affect the redox reaction of active material during charging and discharging. Rate capability tests revealed that the specific capacities with higher slurry pH values were increased at C-rates above C/5. Cells with laser structured thick-film electrodes showed an increase in capacity by 40 mAh/g in comparison to cells with unstructured electrodes.

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“…As LiTFSI and LiPF 6 show very equal mole fraction solubilities in DMC of ≈0.2× at room temperature, [ 40 ] it is assumed that the solubility of the salts in the EC/EMC solvent is also very similar. In addition, LiOH was also investigated as processing additive in the electrode paste, as it was previously shown by Ibing et al [ 38 ] to improve the performance of water‐processed cathodes. The other additives were not examined in more detail as they either lead to high pH values such as Li 3 PO 4 and Li 2 CO 3 or introduce harmful components into the cell system (e.g., LiCl) and can therefore lead to undesired side products, such as formation of HCl.…”

Section: Resultsmentioning

confidence: 99%

“…The second strategy is to use a carbon-coated aluminum foil, which is not prone to breakdown at high pH values and additionally increases the electronic conductivity between the current collector and the composite electrode. [26,37] Another advantage of the second method is that LiOH can be added to the electrode paste as suggested by Ibing et al [38] The same authors described, that as LiOH decreases the proton concentration in the aqueous solution and adds lithium ions, the equilibrium in Equation ( 1) is shifted so that hardly any lithium-proton exchange takes place. In addition, Hofmann et al [39] reported that the lithium-proton exchange could be also reduced by a Li 3 PO 4 coating, which also benefits the pH value.…”

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confidence: 99%

Enabling Aqueous Processing for LiNi_0.5Mn_1.5O₄‐Based Positive Electrodes in Lithium‐Ion Batteries by Applying Lithium‐Based Processing Additives

Dienwiebel

Diehl

Heidrich

et al. 2021

Adv Energy and Sustain Res

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Aqueous processing of positive electrode active materials (AMs) could enable a more economical and environmentally friendly production of lithium‐ion batteries. Intrinsically, aqueous processing of positive AMs is hampered by lithium‐proton exchange in the AM surface, leading to a poor electrochemical performance and a resulting strong increase in the pH value in the electrode paste, thereby corroding the aluminum current collector. Herein, the influence of different lithium salts as processing additive to tailor the pH value of the electrode paste, the manganese dissolution during processing, and the electrochemical performance is described for aqueous processing of LiNi0.5Mn1.5O4‐based positive electrodes. Positive electrodes, based on an aqueous LiNi0.5Mn1.5O4‐based electrode paste which is mixed with LiN(SO2CF3)2 (LiTFSI), achieve a comparable electrochemical performance to state‐of‐the‐art nonaqueous‐processed electrodes. Manganese dissolution into the electrode paste is examined by inductively coupled plasma‐mass spectrometry (ICP‐MS), showing that the addition of lithium salts to the electrode paste substantially decreases manganese leaching during processing. Furthermore, postmortem analysis shows that the addition of LiTFSI to the electrode paste has a positive effect not only during processing but also on charge/discharge cycling performance.

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The role of the pH value in water-based pastes on the processing and performance of Ni-rich LiNi0.5Mn0.3Co0.2O2 based positive electrodes

Cited by 19 publications

References 38 publications

From Materials to Cell: State-of-the-Art and Prospective Technologies for Lithium-Ion Battery Electrode Processing

From Materials to Cell: State-of-the-Art and Prospective Technologies for Lithium-Ion Battery Electrode Processing

Characterization and Laser Structuring of Aqueous Processed Li(Ni0.6Mn0.2Co0.2)O2 Thick-Film Cathodes for Lithium-Ion Batteries

Enabling Aqueous Processing for LiNi_0.5Mn_1.5O₄‐Based Positive Electrodes in Lithium‐Ion Batteries by Applying Lithium‐Based Processing Additives

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The role of the pH value in water-based pastes on the processing and performance of Ni-rich LiNi0.5Mn0.3Co0.2O2 based positive electrodes

Cited by 19 publications

References 38 publications

From Materials to Cell: State-of-the-Art and Prospective Technologies for Lithium-Ion Battery Electrode Processing

From Materials to Cell: State-of-the-Art and Prospective Technologies for Lithium-Ion Battery Electrode Processing

Characterization and Laser Structuring of Aqueous Processed Li(Ni0.6Mn0.2Co0.2)O2 Thick-Film Cathodes for Lithium-Ion Batteries

Enabling Aqueous Processing for LiNi0.5Mn1.5O4‐Based Positive Electrodes in Lithium‐Ion Batteries by Applying Lithium‐Based Processing Additives

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Enabling Aqueous Processing for LiNi_0.5Mn_1.5O₄‐Based Positive Electrodes in Lithium‐Ion Batteries by Applying Lithium‐Based Processing Additives