Synergistic in-situ intercalation and surface modification strategy for Ti₃C₂T_x MXene-based supercapacitors with enhanced electrochemical energy storage

Ti3C2Tx MXene with unique physicochemical properties is a promising negative electrode for high performance supercapacitors, but its full potential for energy storage is limited by inherent restacking and unfavorable -F surface termination. Here, a synergistic in-situ intercalation and surface modification strategy for enhancing the electrochemical performance of Ti3C2Tx is demonstrated. Ag nanoparticles were intercalated into the interplanar s of Ti3C2Tx using an in-situ reduction method to open ion diffusion channels and expose active sites, followed by annealing treatment to remove the deleterious termination. Benefitting from the structural modification, the obtained a-Ag/Ti3C2Tx film electrode possess an enhanced specific capacitance of 471 F g(-1) at 1 A g(-1) with a 2-fold increase in intercalation pseudocapacitance compared to the pristine Ti3C2Tx, accompanied by improved rate performance and cyclic stability. Furthermore, the asymmetric supercapacitor with a negative electrode of aAg/Ti3C2Tx and a positive electrode of RuO2@CC delivers a high energy density of 24.6 Wh kg(-1). The present study demonstrates an effective strategy to improve the electrochemical energy storage of the Ti3C2Tx negative electrode by designing the intercalation and termination.