Multitasking tartaric-acid-enabled, highly conductive, and stable MXene/conducting polymer composite for ultrafast supercapacitor

Ti₃C₂T_x (MXene), a thriving member of the two-dimensional (2D) materials family, has shown increasing potential in a myriad of applications, ranging from printable electronics to energy storage and separation membranes. Nevertheless, the dilemma of its oxidative instability and the easy disintegration of its assemblies in contact with water has been restricting its real-life use. Here, we report the benefits of tartaric acid, a natural source, as a non-innocent additive in the MXene composite. In water, it can, above all, inhibit oxidation of Ti₃C₂T_x and hold individual components in the composite Ti₃C₂T_x/poly(3,4-ethylenedioxy thiophene):polystyrene sulfonate) (Ti₃C₂T_x/PEDOT:PSS) firmly together; equally important, it can boost 4-fold the composite's electron conductivity in comparison to the additive-free equivalent. To showcase its practical value, a tartaric-acid-treated, water-stable MXene/PEDOT:PSS conductive coating is made, which serves as electrodes for an ultrafast supercapacitor; among all 2D materials-based assemblies, the designed supercapacitor delivers, to our knowledge, the record-high performance in an alternating-current filtering application.