The Effect of Crystalline Microstructure of PVDF Binder on Mechanical and Electrochemical Performance of Lithium-Ion Batteries Cathode

Abstract

In this paper, the effect of the crystalline microstructures of polyvinylidene fluoride (PVDF), as cathode binder, on mechanical and electrochemical properties of the cathode, and on the cell performance is investigated. The crystalline phases of the PVDF films prepared at different temperatures are determined by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) and also mechanical strength of PVDF films evaluated by a tensile test. The cathodes were prepared at altered temperatures to achieve different PVDF phases. The effect of various crystalline phases on the cathode performance was studied. The obtained cathodes were analyzed by scanning electron microscope (SEM), contact angle measurement, and adhesion test. The electrochemical performance of the cathodes was evaluated by charge-discharge cycling test and AC impedance spectroscopy. Mechanical tests results showed that the cathode which is prepared at 60 °C has the best adhesion and mechanical stability. In addition, the charge-discharge cycling studies showed that this cathode has the highest capacity efficiency. AC impedance spectroscopy illustrated that this electrode has the lowest charge transfer resistance and SEI resistance.

Impact of Binder Functional Groups on Controlling Chemical Reactions to Improve Stability of Rechargeable Zinc-Ion Batteries

“…In addition, the PVDF-based ZIB had the best rate capability compared to the ZIB with CMC and CA binders. This was due to the strong electron-withdrawing functional group (−C–F) and the high dielectric constant in PVDF, − which tends to improve ion transportation, helps draw in positively charged ions such as Zn 2+ , and provides a high concentration of the charge carrier . However, the PVDF binder needs to absorb a large amount of electrolytes to enable ion transport, which unavoidably leads to degradation of the electrode during long cycling and results in capacity fading .…”

Calendering of Li(Ni0.33Mn0.33Co0.33)O2‐Based Cathodes: Analyzing the Link Between Process Parameters and Electrode Properties by Advanced Statistics

“…In terms of the temperature, both and are smaller as it increases. Being the PVdF a thermoplastic polymer, [25] the increase in the temperature facilitates the polymer deformability and therefore lower porosities can be reached.…”

Sustainable approach for reclamation of graphite from spent lithium-ion batteries

“…The significant improvement in performance is due to the existence of efficient electron withdrawing group as well as higher dielectric constant of the binder. This helps to enrich the transportation of cations and produces the lots of mobile ions [38,39]. In contrast, RG with polystyrene foam reveals poor performance, which may be due to progressive lose of electrical contact, kinetics of ion transport and thereby increasing the resistance and prevents the ion transportation as a result lesser discharging time.…”