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In this study, two green organic solvents are reported in LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NMC111)-based slurry preparation and subsequent cathode fabrication for Li ion batteries. NMC111, conductive carbon and poly(vinylidene fluoride) binder composite slurries prepared with methyl-5-(dimethylamino)-2-methyl-5-oxopentanoate (PolarClean) and dimethyl isosorbide (DMI) exhibit mechanically stable, crack-free uniform coating structures. Both slurries showed similar shear-thinning viscosity behavior that suggests similar processibility during electrode casting and coating. When used as the cathode in Li/NMC111 half cells, the electrode slurries prepared with PolarClean show promising electrochemical performance metrics with an average specific charge capacity of 155 ± 1 mA h g −1 at C/10 over 100 cycles, comparable to the films (152 ± 3 mA h g −1 at C/10) prepared with traditional N -methyl pyrrolidone (NMP) solvent. The use of PolarClean points to a potential route to replace toxic NMP in cathode fabrication without altering the manufacturing process. However, electrodes prepared with DMI demonstrate inferior electrochemical performance with an average charge capacity of 120 mA h g −1 . Nonetheless, DMI may still offer some promising features and warrants further detailed investigation in terms of compatible electrolyte, tailoring the slurry preparation, and casting conditions.
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Direct observation of carbon slurry flow behavior and its effect on electrochemical performance in a microfluidic electrochemical flow capacitor
Carbon slurries have been used as “flowable electrodes” in various electrochemical systems, and the slurry flow characteristics play an important role in the system electrochemical performance. For example, in an electrochemical flow capacitor (EFC), activated carbon particles must pass electrical charge from a stationary electrode to surrounding particles via particle-electrode and particle–particle interactions to store energy in the electric double layer. So far, particle behaviors under a continuous flow condition have not been observed due to the slurry's opacity, and studies of the device's performance thus have been mainly on a bulk level. To understand the relation between the hydrodynamic behavior and the electrochemical performance of carbon slurries, we have constructed a microfluidic EFC (μ-EFC) using transparent materials. The μ-EFC allows for direct observation of particle interactions in flowing carbon slurries using high-speed camera recording, and concurrent measurements of the electrochemical performance via chronoamperometry. The results indicate an interesting dependence of the particle cluster interaction on the flowrate, and its effect on the slurry charging/discharging behavior. It is found that an optimal flowrate could exist for better electrochemical performance.
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- Award ID(s):
- 1921320
- PAR ID:
- 10500312
- Publisher / Repository:
- RSC Publishing
- Date Published:
- Journal Name:
- Nanoscale
- Volume:
- 16
- Issue:
- 4
- ISSN:
- 2040-3364
- Page Range / eLocation ID:
- 1807 to 1816
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D3NR04391F
