Carbon material is widely used and has good electrical and thermal conductivity. It is often used as a filler to endow insulating polymer with electrical and thermal conductivity. Three-dimensional printing technology is an advance in modeling and manufacturing technology. From the forming principle, it offers a new production principle of layered manufacturing and layer by layer stacking formation, which fundamentally simplifies the production process and makes large-scale personalized production possible. Conductive carbon materials combined with 3D printing technology have a variety of potential applications, such as multi-shape sensors, wearable devices, supercapacitors, and so on. In this review, carbon black, carbon nanotubes, carbon fiber, graphene, and other common conductive carbon materials are briefly introduced. The working principle, advantages and disadvantages of common 3D printing technology are reviewed. The research situation of 3D printable conductive carbon materials in recent years is further summarized, and the performance characteristics and application prospects of these conductive carbon materials are also discussed. Finally, the potential applications of 3D printable conductive carbon materials are concluded, and the future development direction of 3D printable conductive carbon materials has also been prospected.

The construction of ionic conductive hydrogels with high transparency, excellent mechanical robustness, high toughness, and rapid self-recovery is highly desired yet challenging. Herein, a hydrogen-bonding network densification strategy is presented for preparing a highly stretchable and transparent poly(ionic liquid) hydrogel (PAM-r-MVIC) from the perspective of random copolymerization of 1-methyl-3-(4-vinylbenzyl) imidazolium chloride and acrylamide in water. Ascribing to the formation of a dense hydrogen-bonding network, the resultant PAM-r-MVIC exhibited an intrinsically high stretchability (>1000%) and compressibility (90%), fast self-recovery with high toughness (2950 kJ m ^-3 ), and excellent fatigue resistance with no deviation for 100 cycles. Dissipative particle dynamics simulations revealed that the orientation of hydrogen bonds along the stretching direction boosted mechanical strength and toughness, which were further proved by the restriction of molecular chain movements ascribing to the formation of a dense hydrogen-bonding network from mean square displacement calculations. Combining with high ionic conductivity over a wide temperature range and autonomous adhesion on various surfaces with tailored adhesive strength, the PAM-r-MVIC can readily work as a highly stretchable and healable ionic conductor for a capacitive/resistive bimodal sensor with self-adhesion, high sensitivity, excellent linearity, and great durability. This study might provide a new path of designing and fabricating ionic conductive hydrogels with high mechanical elasticity, high toughness, and excellent fatigue resilience for skin-inspired ionic sensors in detecting complex human motions.