High supercapacitance performance of nitrogen-doped Ti3C2Tx prepared by molten salt thermal treatment

Ti3C2Tx with -F surface terminations were treated in LiCl-KCl-Li3N molten salt at atmospheric pressure to introduce N and simultaneously remove -F surface terminations, in which LiCl-KCl salt was used as the solvent and Li3N as the nitrogen source. By optimizing the mass ratio of Li3N:Ti3C2Tx to be 1:2, N-doped Ti3C2Tx (N-Ti3C2Tx-0.5) was obtained with 19.6 at% nitrogen element and 0.69 at% -F surface terminations, leading to the substitution of C by N atoms and the D-spacing expansion from 0.96 to 1.15 nm. Owing to its good electrical conductivity and high electrochemical activity area, the N-TTi3C2Tx- 0.5 electrode showed a higher specific capacitance (332 F g(-1) at 0.5 A g(-1) in 1 M H2SO4 solution), good rate performance (83.1% at 20 A g(-1)), and excellent capacitance retention (87.5% after 10 0 0 0 charging-discharging cycles). This paves a new way to achieve MXene electrodes with high specific capacitances and excellent retention performance. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

By introducing nitrogen and removing surface terminations in molten salt, N-doped Ti3C2Tx electrodes with high specific capacitance and excellent retention performance were prepared.