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

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 polarised 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.