Nanohybrid TiN/Vertical graphene for high-performance supercapacitor applications

Transition metal nitrides are promising materials for supercapacitor electrodes owing to their high electrochemical capacity and good chemical stability. However, it remains challenging to control crystallinity, electrical conductivity and electrochemical active sites in the common routes of synthesizing these materials. Here we use a one-step and scalable transferred arc method to prepare TiN nanoparticles, which possess a well-defined cubic crystal structure with a nano-size distribution of 5–20 ​nm. The TiN nanoparticles are then deposited onto plasma-produced vertical graphene (VG) support materials to form hybrid TiN/VG electrodes for supercapacitors. In aqueous Li2SO4 electrolyte operated at a voltage window of 1.0 ​V, the TiN/VG hybrid displays areal capacitance more than four times higher than that of commercial TiN deposited VG hybrid. As the voltage window is expanded to 1.8 ​V, the TiN/VG electrode can achieve areal capacitance of 9.0 ​mF ​cm-2 at a scan rate of 100 ​mV ​s-1 while maintaining 89.5% of the initial capacitance after 10,000 cycles, which are among the highest values reported for TiN nanoparticles. These results indicate that TiN nanoparticles produced by the transferred arc technique are highly promising for energy storage applications.