High-performance all-solid-state flexible asymmetric supercapacitors composed of PPy@Ti3C2Tx/CC and Ti3C2Tx/CC electrodes

Abstract

Supercapacitors have attracted enormous attention for energy storage in the past years. In this study, an all-solid-state flexible asymmetric supercapacitor was assembled with PPy@Ti3C2Tx composite material deposited on carbon cloth (CC) as the positive electrode (PPy@Ti3C2Tx/CC) and the CC with Ti3C2Tx (CC) as the negative electrode (Ti3C2Tx/CC) in the absence of any binder. The PPy@Ti3C2Tx/CC composite electrode was prepared by facile one-step electrochemical co-deposition at a suitable concentration ratio of Ti3C2Tx nanosheets and pyrrole monomers in an aqueous solution. The excellent conductivity of Ti3C2Tx and the porous structure of PPy@Ti3C2Tx/CC composite electrode greatly facilitated the charge’ transfer and ions’ diffusion across the composite films, leading to better utilization of the active materials inside the composite films. As a result, the all-solid-state flexible binder-free PPy@Ti3C2Tx/CC//Ti3C2Tx/CC asymmetric supercapacitor exhibited a large operating voltage of 1.2 V, high energy density of 15.7 Wh kg−1 at the power density of 620.8 W kg−1, and excellent cycling stability (88.7% capacitance retention after 5000 cycles). This work presented a simple and efficient approach to prepare composite electrodes and fabricated all-solid-state asymmetric supercapacitors with high electrochemical performances for flexible electronics.