Additive-Free Homogeneous Dispersion of Conductive Carbon Black via Electrostatic Repulsion for High-Performance Lithium-Ion Batteries

Abstract

Constructing efficient conductive networks with carbon black in lithium-ion batteries remains challenging due to its propensity to agglomerate and its high specific surface area, which hinder dispersion, electron transport, and reaction kinetics. Conventional methods such as intense mechanical mixing or chemical additives often induce side reactions and impair slurry stability. Here, we present an additive-free dispersion strategy that utilizes a high-voltage electrostatic field (HV-EF) to de-agglomerate carbon black via Coulombic repulsion. Molecular dynamics simulations reveal an approximately 38% reduction in system energy under high-voltage electrostatic conditions. Experimentally, HV-EF-assisted stirring decreases the median particle size (D50) by 15.14% and effectively suppresses large agglomerates. Comprehensive characterization through four-point probe resistance, Kelvin probe force microscopy, and distribution of relaxation times confirms that the HV-EF promotes a more homogeneous carbon black distribution, slashing contact resistance by 50% and surface potential fluctuation by 29.17%. Notably, electrodes with only 5 wt % carbon black deliver substantially enhanced electrochemical performance: discharge capacities increase by 12 mAh g–1 at 0.5 C and 32 mAh g–1 at 1 C, coupled with significantly reduced polarization. This work provides an efficient, green dispersion methodology for battery electrodes, establishing a new paradigm for interfacial optimization and performance enhancement.