Influence of hydrochloric acid concentration and type of nitrogen source on the electrochemical performance of TiO2/N-MoS2 for energy storage applications

In this work, nitrogen-doped molybdenum sulfide was directly deposited on titanium dioxide nanotubes substrate (TiO2/N-MoS2) during hydrothermal synthesis. The study focuses on the influence of hydrochloric acid concentration used for the synthesis, with the results indicating its essential role in thioacetamide hydrolysis and thus in the effectiveness of the N-MoS2 deposition. The electrode material itself is characterized by an initial capacitance of 320 mF cm−2 with 76 % capacitance retention after 10 000 cycles. Moreover, the effect of nitrogen source on the physical and capacitive properties is investigated, revealing that the simultaneous addition of aniline and ammonium persulfate contributes to the improvement of crystallinity and overall electrochemical performance of the electrode material. The analysis of charge storage mechanisms also indicates that the introduction of nitrogen atoms significantly affects the contribution of diffusion-controlled processes. In the construction of a symmetrical device, the specific capacitance of 76 F g−1 and areal capacitance of 70 mF cm−2 with the superior coulombic efficiency and 84 % of capacitance retention after 15,000 cycles is observed, with 11.1 W kg−1 and 5193.4 Wh kg−1 of energy and power density of the device, respectively.