Influence of Mixing Process on the Performance of Electrodes Made by a Dry Coating Method

Abstract

Thick NMC-LMO blend positive electrodes were manufactured using dry-powder electrostatic spray deposition (ESD) to avoid the use of unwanted solvents. The effects of two dry powder mixing processes prior to ESD on the dry-made electrodes were investigated by peel tests, electrochemical techniques, and microscopic analyses. Electrodes made using high-speed mixing had a dense carbon black/binder layer on the active materials (AM), limiting their contact area with the electrolyte and decreasing the ionic conductivity. Electrodes made using ball mill mixing exhibited a porous structure, enabling more AM-electrolyte contact, thus improving ionic conductivity and lowering charge transfer resistance.

Effect of PVdF Distribution on Properties and Performance of Dry Spray-Coated Graphite Electrodes for Lithium-Ion Batteries for Electric Vehicle Applications

“…The charged particles are then accelerated towards the grounded current collector, where they form a uniform and continuous coating layer, which is then hot pressed to thermally activate the binder and control the coating thickness and density. This way, both cathodes (LiCoO 2 , 4 LiNi 0.33 Mn 0.33 Co 0.33 O 2 , 19 LiNi 0.5 Mn 0.3 Co 0.2 O 2 , 19 LiNi 0.8 Mn 0.1 Co 0.1 O 2 /LiMn 2 O 4 20 ) and anodes (Li 4 Ti 5 O 12 , 7,21 graphite 20 ) have been prepared, in most cases with PVdF binder. 4,7,[19][20][21] In Schälicke et al's work on graphitebased electrodes, PVdF was judged to be an unsuitable binder for this process, the reason being however that the grade of PVdF used had too large particle sizes (d 50 of 85 μm).…”

“…This way, both cathodes (LiCoO 2 , 4 LiNi 0.33 Mn 0.33 Co 0.33 O 2 , 19 LiNi 0.5 Mn 0.3 Co 0.2 O 2 , 19 LiNi 0.8 Mn 0.1 Co 0.1 O 2 /LiMn 2 O 4 20 ) and anodes (Li 4 Ti 5 O 12 , 7,21 graphite 20 ) have been prepared, in most cases with PVdF binder. 4,7,[19][20][21] In Schälicke et al's work on graphitebased electrodes, PVdF was judged to be an unsuitable binder for this process, the reason being however that the grade of PVdF used had too large particle sizes (d 50 of 85 μm). This is why they obtained better results with a fluorinated ethylene propylene copolymer or a copolymer of tetrafluoro ethylene, hexafluoro propylene, and vinylidene fluoride (d 50 of 5 μm).…”

“…fr electrostatic spray deposition of LiNi 0.8 Mn 0.1 Co 0.1 O 2 /LiMn 2 O 4 /PVdF/ CB (48:48:2:2) electrodes. 20 The powders were mixed either using a high-speed planetary centrifugal mixer (4 cycles of 4 min with revolution speed of 880 rpm, rotation speed of 880 rpm) or a planetary ball mill (60 min at rotation speed of 300 rpm). Electrodes made using the first method had a dense CB/PVdF layer on the active material particles, limiting their contact area with the electrolyte, while electrodes made using the second one exhibited a porous structure, enabling more active material-electrolyte contact, thus lowering charge transfer resistance, improving ionic conductivity and rate performance.…”

Investigating the Structure and Performance of Electrodes Made by Dry and Wet Slurry Processes

“…27,28 At high C-rates, e.g., >3 C, the effectiveness of dry electrodes is hindered by the fracture of active material particles and insufficient long-range pathways. 22,29 The former reduces the available capacity, while the latter limits the fast transfer of ions and electrons, leading to decreased performance. 27,30,31 For slurry electrodes, minimal particle cracking and a more homogenous and porous distribution of the PVDF and CB provided more efficient conductive paths, leading to better performance at high C-rates.…”

Identification of Relevant Parameters for Traceability in the Continuous Mixing Process in Battery Cell Production

“…The corresponding references are noted as comments in the boxes; this is visualized by the small red triangle in the top right‐hand corner. [ 10–13,15,16,18–21,30–168 ]…”