Synthesis of an MXene/polyaniline composite with excellent electrochemical properties

Abstract

As a family member of MXenes, Ti₃C₂T_x has received worldwide interest due to its excellent electrochemical energy storage properties. However, freestanding Ti₃C₂T_x films synthesized by direct assembly of two-dimensional (2D) sheets have relatively low specific capacitance and rate capability due to the low ion transport efficiency between Ti₃C₂T_x (MXene) sheets. Here, we demonstrate an effective method to improve the electrochemical performance of MXene-based electrodes by incorporating MXene sheets with conducting polymers. A Ti₃C₂T_x/polyaniline (MXene/PANI) composite was fabricated by chemical oxidative polymerization of aniline monomers on the surface of Ti₃C₂T_x sheets. Benefiting from the highly conductive open structure, efficient ion and electron transport and high electrochemical activity of Ti₃C₂T_x and PANI, the MXene/PANI electrode presents a maximum specific capacitance of 556.2 F g⁻¹ at a current density of 0.5 A g⁻¹, an impressive rate capability (high capacitance retention of 78.7% at 5 A g⁻¹) and excellent cycling stability with a high capacitance retention of 91.6% after 5000 cycles at 5 A g⁻¹. Therefore, this paper provides a facile and effective method to achieve high performance MXene-based electrode materials for supercapacitors.