Dopamine-derived N-doped carbon decorated titanium carbide composite for enhanced supercapacitive performance. (10th November 2017) - Zhao, Tongkun
Graphical abstract: Highlights: Ti3 C2 Tx @NC is prepared by in-situ dopamine self-polymerization and carbonization. NC intercalation prevents Ti3 C2 Tx sheet re-stacking and forms 3D composites. NC enhances electrical conductivity and provides electroactive sites to composite. NC significantly enhances the specific capacitance of Ti3 C2 Tx by 281%. The intercalated structure offers adequate cycling stability to Ti3 C2 Tx @NC. Abstract: Two-dimensional transition metal carbides, MXenes, with large surface area, excellent electrical conductivity and chemical stability, have proved promising for energy storage. However, the irreversible re-stacking and low capacity of MXenes restrict their development and practical applications. Here, the N-doped carbon decorated MXene (Ti3 C2 Tx @NC) composites were synthesized via an in-situ self-polymerization of dopamine on the surface of Ti3 C2 Tx followed by a carbonization process. The Ti3 C2 Tx and Ti3 C2 Tx @NC were systematically characterized, which have been manifested that NC were equably decorated on the surface and interlayer of Ti3 C2 Tx sheets and a unique three-dimensional composited nanostructure was fabricated. Such nanostructure can confer both high surface area of NC layer and effective avoidance of the restacking of Ti3 C2 Tx sheets, whilst, importantly, rendering the composites good conductivity and additional pseudocapacitance. As a result, the optimized Ti3 C2 Tx @NC-2 composite exhibited a high specific capacitance of 442.2 F g −1 under a current density of 1 A g −1, which is 281% higher than that of Ti3 C2 Tx . As a further description, Ti3 C2 Tx @NC achieved an excellent cycling stability with capacitance retaining 91.9% after 5000 cycles and a high rate capability of 92.5% at 10 A g −1 . Besides, the Ti3 C2 Tx @NC-2-based symmetric supercapacitor presents a delighted energy density and power density. Therefore, the elaborately designed Ti3 C2 Tx @NC composites provided a pregnant exploration for energy-related applications.