This study demonstrates an all-graphene, additive-free, aqueous-based ink for direct ink writing (DIW) to 3D-print functional aerogels for applications in electronics and electromagnetic interference (EMI) shields. We employ a two-step electrochemical method with a specially designed intercalation step that controls the surface functionality of graphene nanosheets. Comprehensive characterization reveals the significant impact of the physicochemical properties of graphene nanosheets on homogeneity, rheology, electrical conductivity, and EMI shielding effectiveness (SE). A critical observation is that rheology alone is insufficient to predict the printability of two-dimensional particulate systems, while ink homogeneity, dictated by inter-sheet interactions, plays a vital role. By focusing on optimizing intercalation conditions, we find that phosphoric acid treatment is most effective in enhancing both printability and conductivity, achieving an electrical conductivity of 158 S cm⁻¹ and an EMI SE of 50 dB (at 50 μm thickness) without requiring any post-processing reduction. Systematic experiments with varying durations of phosphoric acid intercalation establish that a 10-minutes treatment produces inks with superior 3D printing fidelity. This innovative approach to graphene ink production enables rapid, continuous, and large-scale manufacturing of lightweight, porous materials, avoiding the need for environmentally harmful reductant chemistries or high-temperature processing. Furthermore, eliminating the reduction step in the fabrication process aligns with industrial demands for energy-efficient production processes and high output rates, marking a significant advancement in the field of materials science and offering promising prospects for applying graphene-based inks in advanced manufacturing technologies.

中文翻译：

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用于 3D 打印功能性导电气凝胶的无添加剂石墨烯墨水


这项研究展示了一种全石墨烯、无添加剂、水基墨水，用于直接墨水书写 (DIW) 到 3D 打印功能性气凝胶，用于电子和电磁干扰 (EMI) 屏蔽。我们采用两步电化学方法和专门设计的插层步骤来控制石墨烯纳米片的表面功能。综合表征揭示了石墨烯纳米片的物理化学性质对均匀性、流变性、导电性和 EMI 屏蔽效能 (SE) 的显着影响。一个关键的观察是，仅流变学不足以预测二维颗粒系统的印刷适性，而由片材间相互作用决定的油墨均匀性起着至关重要的作用。通过专注于优化插层条件，我们发现磷酸处理在增强可印刷性和导电性方面最有效，无需任何后处理即可实现 158 S cm ^-1的电导率和 50 dB 的 EMI SE（50 μm 厚度） -加工减少。采用不同磷酸嵌入时间的系统实验表明，10 分钟的处理可产生具有卓越 3D 打印保真度的墨水。这种石墨烯墨水生产的创新方法可以快速、连续、大规模地制造轻质多孔材料，避免使用对环境有害的还原剂化学物质或高温处理。 此外，消除制造过程中的还原步骤符合工业对节能生产过程和高产出率的需求，标志着材料科学领域的重大进步，并为石墨烯基油墨在先进制造技术中的应用提供了广阔的前景。