Planar supercapacitor with high areal capacitance based on Ti3C2/Polypyrrole composite film

The planar supercapacitor with interdigital electrodes has attracted a great deal of attention for its flexibility, portability and safety. In this paper, we use an effective method to fabricate planar supercapacitor through electrophoretic deposition and electrochemical polymerization based on Ti3C2/PPy interdigital electrodes. The supercapacitor shows an areal capacitance of 109.4 mF/cm2 in 2M H2SO4 and 86.7 mF/cm2 with PVA/H2SO4 solid-state electrolyte at current density of 1.05 mA/cm2. Besides, the planar supercapacitors also present good cycling stability with 96% of capacity retention after 10000 cycles. The good electrochemical performance can be attributed to the synergistic effect of the Ti3C2 and PPy that Ti3C2 nanosheets provide a stable 2D conductive channel for ion transfer and PPy improves the pseudocapacitive performance. Furthermore, we combined the supercapacitor with a solar cell to form an integrated self-powered energy conversion-storage device, which shows high practicability. The two-step deposition&polymerization method may also be extended to other MXene and electrochemical active polymers on the fabrication of planar symmetric supercapacitor.