Effect of Calendering on Electrode Wettability in Lithium-Ion Batteries

Abstract

Controlling the wettability between the porous electrode and the electrolyte in lithium-ion batteries can improve both the manufacturing process and the electrochemical performance of the cell. The wetting rate, which is the electrolyte transport rate in the porous electrode, can be quantified using the wetting balance. The effect of the calendering process on the wettability of anode electrodes was investigated. A graphite anode film with an as-coated thickness of 59 µm was used as baseline electrode film and was calendered to produce films with thickness ranging from 55 to 41 µm. Results show that wettability is improved by light calendering from an initial thickness of 59 µm to a calendered thickness of 53 m where the wetting rate increased from 0.375 to 0.589 mm/s 0.5 µ. Further calendering below 53 µm resulted in a decrease in wetting rates to a minimum observed value of 0.206 mm/s 0.5 at a calendered thickness of 41 µm. Under the same electrolyte, wettability of the electrode is controlled to a great extent by the pore structure in the electrode film, which includes parameters such as porosity, pore size distribution, pore geometry and topology. Relations between the wetting behavior and the pore structure as characterized by mercury intrusion and electron microscopy exist and can be used to manipulate the wetting behavior of electrodes.

Controlling the Wettability between Freestanding Electrode and Electrolyte for High Energy Density Lithium-Sulfur Batteries

“…37,39,40 In that regard, we investigated the effects of wettability induced by changing the viscosity of the electrolyte. First, in order to confirm the wettability of between the electrolytes on the pressed MWCNT-S electrode, we measured the contact angles.…”

Anomalously Faster Deterioration of LiNi0.8Co0.15Al0.05O2/Graphite High-Energy 18650 Cells at 1.5 C than 2.0 C

“…The MIP could measure pore diameters from a nanometer to micrometer scale, which matched well with the pore range in the electrode film sample compared to nano-computed tomography (CT) just monitoring the pore diameters above 500 nm [31, 32]. Scanning electron microscopy (SEM) was carried out to observe the surface microscopic morphology changes of the positive and negative electrodes for fresh and aged cells.…”

Influence of Electrode Density on the Performance of Li-Ion Batteries: Experimental and Simulation Results

“…To achieve a maximal wettability, it is important that the electrolyte completely permeates and fills the pores in the separator and electrode [10]. Un-wetted AM area will decrease the specific surface area which is reacting during battery operation and as result increase the cell impedance.…”

“…In practice, many manufacturing parameters are chosen based on experience rather than analysis and calculation. Recent work has shown the potential gain in tuning and further developing LIB manufacturing [8][9][10][11]. For instance, in reference [8], the potential for a cost reduction of increasing the electrode thickness is demonstrated and, in reference [10], the influence of calendering on wettability is investigated.…”

“…Recent work has shown the potential gain in tuning and further developing LIB manufacturing [8][9][10][11]. For instance, in reference [8], the potential for a cost reduction of increasing the electrode thickness is demonstrated and, in reference [10], the influence of calendering on wettability is investigated. Initial and lifetime performance are strongly influenced by interventions in the manufacturing process, especially the morphology of the porous electrode [11].…”