A binder material in a battery electrode is a polymer (often a type of plastic like PVDF or styrene butadiene rubber (SBR) for different chemistries) that acts like a glue. It holds together the anode and cathode active material powders (like graphite or NMC, respectively) and any conductive additives, forming a cohesive electrode coating. The binder also secures this mixture onto the metal foil current collector (aluminum for cathodes, copper for anodes). Although the binder doesn’t participate electrochemically in energy storage, it is crucial for mechanical integrity, as it ensures the electrode coating has good cohesion between other active particles and good adhesion to the current collector during manufacturing and repeated battery cycling, especially when particles expand and contract as lithium is inserted and removed.
NOVONIX studies how different binder formulations and contents impact battery performance. For example, a stronger binder might improve cycle life by preventing particle detachment, but too much binder can impede electrical conductivity or ion diffusion if it insulates active particles. Additionally, since the binder is an inactive component in an electrode, too much binder can decrease the amount of energy stored per unit mass of a battery cell. NOVONIX’s testing can reveal how binders contribute to internal resistance or limit rate performance. By experimenting with new binder chemistries (like water-based binders for environmentally friendly manufacturing) and optimizing their use, NOVONIX aims to improve battery durability and manufacturing sustainability without sacrificing performance.
