Ti3C2Tx supported cross-linked polyaniline nanorods with the significantly-improved capacitive performance for flexible solid-state symmetric supercapacitors

Polyaniline (PANI) is extensively utilized as the electrode material of supercapacitors. Nevertheless, its capacitive performance is still unsatisfactory due to its limited electrical conductivity, volume change during charging and discharging, and buried active sites. In this paper, Ti3C2Tx supported cross-linked polyaniline nanorods (C-PANI/Ti3C2Tx) were prepared by in-situ polymerization of aniline on Ti3C2Tx nanosheets using triphenylamine (TPA) as a crosslinking agent and p-phenylenediamine (PPDA) as a chain extender. The crosslinked skeleton of C-PANI and Ti3C2Tx nanosheet substrate improve the conductivity of composites, inhibit the volume change of PANI, and expose more active sites to facilitate electron/ion transport, thus endowing composites with excellent capacitive performance. C-PANI/Ti3C2Tx-4 exhibits a specific capacitance of 489.5 F/g at 1 A/g (409.5 F/g even at 20 A/g) and the capacitance retention of 86.6 % after 5000 cycles, which is significantly better than PANI, C-PANI and some reported PANI-based composites. Electrochemical investigation has shown that capacitance contributes more to the total charge of the reaction than diffusion-controlled process. The assembled flexible solid-state symmetric supercapacitor (FSSC) shows a high energy/power output performance (28.6 Wh/kg at 287.9 W/kg) and bending performance. Thus, Ti3C2Tx supported cross-linked PANI nanorods and its FSSC show great potential in wearable and portable electronic devices.