Preparation of Polyaniline onto dl-Tartaric Acid Assembled MXene Surface as an Electrode Material for Supercapacitors

Polyaniline (PANI)/MXene composites have been widely studied for high performance supercapacitors because of the combination of the electric double layer capacitance and pseudocapacitance. In this paper, dl-tartaric acid (DLTA) was first assembled on the surface of MXene to achieve supramolecular self-assembly, where the electronegative oxygen groups can then induce the polymerization of PANI. The analysis of Fourier transform infrared spectroscopy, ultraviolet spectrum, X-ray diffraction, Raman, and X-ray photoelectron spectroscopy confirmed the successful polymerization of PANI, the interactions between MXene-DLTA and PANI, and the doping effect of DLTA. The obtained 3D composite and doping microstructure are beneficial to the transfer of the electrons and ions, thus facilitating the improvement of electrochemical performances. As a result, the as-prepared composite (TDP2) electrode exhibits a specific capacitance of 452 F/g in 1 M H2SO4 electrolyte, which is higher than either composite constituent (61 F/g for MXene and 263 F/g for polyaniline). The working potential window of the composites is enlarged to 1.9 V. The symmetric supercapacitor assembled with the TDP2 as electrodes and poly(vinyl alcohol) (PVA)–H2SO4 gel as solid state electrolyte shows an areal capacitance of 710 mF/cm2 and good cycling stability.