Stable aqueous carbon inks, with graphene sheets (GSs) and carbon black (CB) as conductive fillers, are prepared by a simple one-pot ball-milling method. The as-prepared composite ink with 10 wt% GSs shows optimized rheological properties (viscosity and thixotropy) for screen printing. The as-printed coatings based on the above ink are uniform and dense on a polyimide substrate, and exhibit a sandwich-type conductive three dimensional network at the microscale. The resistivity of the typical composite coating is as low as 0.23±0.01 Ω cm (92±4 Ω sq⁻¹, 25 µm), which is 30% as that of a pure CB coating (0.77±0.01 Ω cm). It is noteworthy that the resistivity decreases to 0.18±0.01 Ω cm (72±4 Ω sq⁻¹, 25 µm) after a further rolling compression. The coating exhibits good mechanical flexibility, and the resistance slightly increases by 12% after 3000 bending cycles. With the CB/GSs composite coatings as a flexible conductor, fascinating luminescent bookmarks and membrane switches were fabricated, demonstrating the tremendous potential of these coatings in the commercial production of flexible electronics and devices.

通过简单的一锅式球磨法制备具有石墨烯片（GSs）和炭黑（CB）作为导电填料的稳定的水性碳素墨水。所制备的具有10 wt％GSs的复合油墨显示出用于丝网印刷的最佳流变特性（粘度和触变性）。基于上述油墨的印刷后涂料在聚酰亚胺基材上均匀且致密，并在微尺度上显示出夹心型导电三维网络。典型的复合涂层的电阻率是低达0.23±0.01Ω厘米（92±4Ω平方^-1，25微米），这是30％的作为一个纯粹的CB涂层（0.77±0.01Ω厘米）的。值得注意的是，电阻率降低到0.18±0.01Ωcm（72±4Ωsq ^-1，25 µm）。涂层表现出良好的机械柔韧性，并且在3000次弯曲循环后电阻略微增加了12％。使用CB / GSs复合涂层作为柔性导体，可以制造出引人入胜的发光书签和薄膜开关，从而证明了这些涂层在柔性电子产品和设备的商业化生产中的巨大潜力。