The multiple synthesis of 2D layered Ti3C2Tx/Ag/MWCNTs/Ag composites with enhanced electrochemical properties

MXene, a novel two-dimensional material composed of alternating transition metal carbon/nitrogen, has the advantages of large specific surface area, many active sites, and short ion transport paths, and has shown great potential in the field of capacitors in the beginning. However, the unique two-dimensional structure is prone to collapse and accumulation, which inhibits the electron migration rate and ion penetration, resulting in poor energy storage capacity. In this paper, Ti₃C₂T_x/Ag/MWCNTs/Ag composites with good capacitive properties were successfully prepared by Ti₃C₂T_x which directly reduces silver nitrate solution and further introduces nanoscale MWCNTs. Ag NPs are introduced twice to grow and distribute uniformly on the surface and between the layers of Ti₃C₂T_x to play a supporting role. The introduction of MWCNTs in the intermediate process can enter the interlayer and act as spacers together with Ag NPs to prevent the collapse and stacking of Ti₃C₂T_x and improve its surface utilization. However, the preparation process unavoidably leads to partial oxidation of Ti₃C₂T_x, which deteriorates its electrochemical properties. Owing to the synergy between Ti₃C₂T_x, Ag NPs and MWCNTs, the Ti₃C₂T_x/Ag/MWCNTs/Ag composites show good electrical conductivity, low internal resistance (0.67 Ω) and extreme high capacitance contribution (97%) in electrochemical tests.