Fabrication of PANI@Ti3C2Tx/PVA hydrogel composite as flexible supercapacitor electrode with good electrochemical performance.

Developing a new strategy to effectively prevent the restacking of MXene nanosheets will have significant impacts on designing flexible supercapacitor electrodes. Herein, a novel Ti 3 C 2 T x /polyvinyl alcohol (PVA) porous sponge with 3D interconnected structures is prepared by sol-gel and freeze-dried methods. This Ti 3 C 2 T x /PVA porous sponge is used as the template of in-situ polyaniline (PANI) polymerization, and the fabricated PANI@Ti 3 C 2 T x /PVA hydrogel composite is applied as flexible supercapacitors electrodes. 1D conductive polymer chains PVA could increase the interlayer spacing of Ti 3 C 2 T x nanosheets, which is beneficial to expose more electrochemical active sites. The supercapacitor based on PANI@Ti 3 C 2 T x /PVA hydrogel composite exhibits the coexistence of double-layer capacitance and pseudocapacitance behavior. This supercapacitor shows a maximum areal specific capacitance of 103.8 mF cm−2 at 2 A m−2, and it also exhibits a maximum energy density of 9.2 μWh·cm−2 and an optimum power density of 800 μW cm−2. The capacitance of this supercapacitor is almost not change under different bending angles. Moreover, 99% capacitance retention is achieved after 10 000 charge/discharge cycles of the supercapacitor. The synergistic effect between PANI and Ti 3 C 2 T x /PVA composite may improve the number of reactive sites and provide efficient channels for ion diffusion/electron transport. [ABSTRACT FROM AUTHOR]