High‐Yield MILD Synthesis of Ti 3 C 2 T x MXene: Characterization and Application in Developing Energy Storage Device

Abstract The Minimally Intensive Layer Delamination (MILD) process to synthesize MXene introduces incomplete etching, and the etched MXenes are primarily laminated. Hence, delamination and the separation of delaminated MXenes from impurities is critical and results in low yield. This study demonstrates post‐processing techniques involving repeated ultrasonication followed by centrifugation of the initial etched MXene (DI‐MXene) solution, which results in a highly delaminated, impurity‐free supernatant with a higher yield. This delaminated MXene (DI‐uMXene) exhibits improved specific capacitance (402 F g −1 ) and conductivity (210 S cm −1 ) compared to DI‐MXene (238 F g −1 and 150 S cm −1 , respectively). Further washing of DI‐MXene with HCl acid instead of DI water is explored as an alternate LiF removal method. This process removes intercalated Li + ions, reducing inter‐layer spacing and specific capacitance. Nonetheless, conductivity is improved to 390 S cm −1 because of the removal of non‐conductive LiF. The study also reports that DI‐uMXene's capacitance is primarily surface‐controlled with low Warburg impedance. Finally, an asymmetric coin cell supercapacitor device is constructed using the DI‐uMXene as the negative electrode, and their electrochemical performances are studied. The results provide an insight into the importance of collection and washing parameters in tailoring the electrochemical properties of MXene for energy storage devices.