A Dispersant-Driven Carbon-Binder Domains Homogeneity in High-Energy-Density Electrodes for Lithium-Ion Batteries

Achieving high energy density in lithium-ion batteries (LIBs) requires electrodes with a high fraction of active materials. An extreme reduction of inactive components such as conductive additives and binders can limit electron transport and undermine electrode integrity, thereby deteriorating the electrochemical performance. To address these limitations, the formation of a well-structured carbon-binder domain (CBD) through effective dispersion of binder and conductive additives is crucial. Herein, we tune component compatibility in polyvinylidene fluoride (PVDF)-carbon nanotubes (CNTs) systems using an aromatic-functionalized polyacrylate (AFPA), which enhances π-π interactions with CNTs and improve PVDF affinity. This approach promotes uniform binder distribution and enhances transport pathways, affecting the crystalline phase and reinforcing mechanical cohesion within the CBD. AFPA stabilizes PVDF in the α-phase, whereas conventional hydrogenated nitrile butadiene rubber (HNBR) exhibits poor compatibility, leading to phase separation and β-phase formation. This structural optimization facilitates interconnected electron/ion pathways and well-connected pores under reduced inactive content and high mass loading. As a result, the AFPA-based electrode delivers superior electrochemical performance even at a CNT content as low as 0.425 wt%. These findings establish CBD microstructural control as a key design parameter for achieving high-energy-density electrodes with minimized inactive content, providing a pathway toward next-generation LIBs.