Intercalating Ni2+/aniline into Ti3C2Tx for supercapacitor to enhance the electrochemical stability

Ti 3 C 2 T x (TC) shows fascinating application prospects in energy storage field, but its practical applications are limited by the self-stacking and its susceptibility to oxidation. Herein, Ni 2+ /aniline co-intercalated Ti 3 C 2 T x (TC-NA) is prepared by intercalating Ni 2+ /aniline into Ti 3 C 2 T x through a simple ultrasonic and filtration process. On one hand, introducing Ni 2+ and aniline into Ti 3 C 2 T x induces self-assembly of Ti 3 C 2 T x to form 3D-like porous network structure, expanded interlayer spacing and increased electrochemical active sites, which are beneficial to improve its electrochemical performance. On the other hand, the interaction between Ni 2+ and terminal groups of Ti 3 C 2 T x , as well as interaction between aniline and Ti 3 C 2 T x help to passivate Ti 3 C 2 T x to improve the electrochemical stability. At scan rate of 2 mV s −1 , the TC-NA achieves a specific capacitance of 217.6 F g −1 in 1 M H 2 SO 4 employing two-electrode system, and retain 83.5% of its initial capacitance after 10,000 cycles at current density of 5 A g −1 , which is significantly superior to TC (48.8%). Furthermore, after being stored for 470 days, the TC-NA can still retain 67.3% of its initial capacitance after 7000 cycles (TC only 28.1%). This work provides a new idea for improving the electrochemical performance, especially cycling stability of MXene-based materials.