Solvation‐Modulated Dispersions of Reduced Graphite Oxide Toward Binder‐Free Conductive Inks

ABSTRACT Conductive inks formulated from graphene‐based materials are essential for translating graphene's potential into real‐world applications. High‐concentration inks are particularly valuable, enabling fewer deposition steps, reduced drying costs, and improved film uniformity. However, increasing graphene concentration typically leads to a steep rise in viscosity, limiting compatibility with most printing techniques. In this work, we address this challenge by compacting expanded reduced graphite oxide into dense‐block reduced graphite oxide, termed DB‐rGtO, allowing the formulation of stable dispersions of graphene‐derived material at concentrations up to 200 mg·mL −1 , while maintaining manageable flowability and deformation resistance. We demonstrate that solvation of DB‐rGtO particles serves as a fundamental strategy to modulate ink viscosity, enabling property tuning at high solids content. The degree of solvation, quantified using polarized light microscopy, correlates well with viscosity predictions based on the Krieger–Dougherty model. Using nitrogen‐doped expanded reduced graphite oxide as the starting material, this approach enables single‐pass printed films and patterns with conductivities ranging from 5 to 10 Ω·□ −1 . Our findings establish general design rules for formulating concentrated, conductive graphene‐based inks with little to no additive, adaptable across various deposition techniques for producing high‐resolution, high‐fidelity features.