59 E-Mobility Engineering | January/February 2026 Battery electrode binders | Product focus or foil backing materials. This uniformity is critical for achieving high electrode density, optimal electronic conductivity and efficient ion transport within the electrode matrix. It also has a high melting point and good thermal resistance, representing an additional safety benefit. Moreover, its good wettability means that it absorbs liquid electrolyte well, which helps ion transport; its amorphous region is a good matrix for polar molecules, meaning that lithium ions can pass through the layer of swollen PVDF. Its inherent hydrophobicity also helps prevent moisture uptake. However, the NMP solvent is a toxic volatile organic compound (VOC), which the industry is under pressure to move away from. It is also tightly regulated and requires closed-loop recovery systems that add cost and complexity. PVDF is also electrically and ionically insulating, which necessitates the use of conductive additives such as carbon black to establish percolation networks that support electrical conductivity. The liquid electrolyte in the electrode’s pores supports ionic conductivity. While PVDF is generally a strong binder, it has difficulty with materials that exhibit high expansion, such as silicon anodes that expand by around 300% when they take up lithium ions during charging. Obviously, this is not a problem for PVDF as a cathode binder. PVDF also comes with additional costs from the fluorine-based chemical supply chain that, together with the energy- and capital-intensive nature of NMP processing, provide economic incentives to move to alternatives such as aqueous binders, which use water as the solvent. Today, PVDF remains the industry standard for cathodes, although research and development continue, focusing on tailor-made solutions to enhance binder performance without compromising safety. Several grades with different molecular weights are available to combine adhesion properties and advantages in electrode manufacturing. Enhanced intermolecular interactions between the polymer, active material and metal collector result in improved performance in terms of adhesion and chemical resistance. These effects translate into higher energy density because the binder content can be significantly reduced, while lower internal resistance allows for increased power density. materials because they require longterm reliability and high chemical and electrochemical resistance within the specific environment of lithium cells. In automotive applications, performance at elevated temperatures is also required. A binder should possess high chemical and electrochemical stability in the reaction environment. In this way, electrical and ionic conductivity are maintained through close contact between particles and good homogeneity. PVDF’s electrochemical stability – thanks in significant measure to the stability of fluorinated polymers – is one of the reasons it became the industry standard. It is safe to use in cells of up to around 4.5 V (compared with a standard Li/Li+ reference electrode), meaning that it does not undergo oxidation (loss of electrons) or reduction (gain of electrons) within the voltage window of common cathode materials. For a cathode binder, the primary threat is oxidation at high voltage because the cathode operates at a high potential during charging. It also resists oxidation and degradation from exposure to the electrolyte. Secondly, its good adhesion stems from its formation of strong van der Waals and dipole–dipole interactions with active materials and the aluminium current collector. The van der Waals force is a distance-dependent attraction between atoms or molecules that is not based on chemical bonds but on forces that occur between neutral atoms and molecules due to temporary fluctuations in electron density, leading to induced dipoles. Attraction between the positive end of one dipole and the negative end of another also contributes to PVDF binders’ good adhesion, minimising the risk of electrode delamination. PVDF also dissolves easily in organic solvents, the type used most commonly being N-Methyl-2-pyrrolidone (NMP), which allows uniform dispersion of active materials and conductive additives, and consistent coating of slurry on polymer Kynar HSV series PVDF binders offer easy processing, high adhesion with lower loading, less swelling of electrolyte, lower resistivity, plus high-voltage stability (Image: Arkema)
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