Synchronous Dual Roles of Copper Sulfide on the Insulating PET Fabric for High-Performance Portable Flexible Supercapacitors

In recent years, low-cost wearable energy storage devices attract much more attention. In this work, the PET/CuS/PPy composite electrodes are fabricated for portable flexible solid-state supercapacitors (FSSC), originating from the insulating PET fabric substrate. In this occasion, the functional layer of copper sulfide (CuS) are designed and chemically deposited on the insulating PET fabric to synchronously develop its dual functions such as high electrical conductivity and large capacitance. As a result, the PET/CuS/PPy electrode shows a high specific capacitance of 5410 mF cm(-2) at 2 mA cm(-2) and good cyclic stability (retaining 84.1% after 2000 cycles). This excellent recyclable specific capacitance is ascribed to the outstanding homogenous binder-free conductive morphologies of CuS and PPy, forming the rapid electronic and ionic transfer channels. Especially, the synchronous dual functions of CuS including high electrical conductivity and large capacitance play a more important role in the large specific capacitance. The flexible solid state supercapacitor (FSSC) also bears a superior specific capacitance of 1335 mF cm(-2) (10.1 F cm(-3)) at 2 mA cm(-2) and an outstanding energy density of 1.4 mW h cm(-3) at the power density of 8.4 mW cm(-3), together with fine flexibility and cyclic stability. Four serially connected FSSC devices can easily supply the electric power for LED indicator lights, calculators, and electric fans, indicating the prospective practical applications in portable flexible energy storage devices. This work provides a facile approach to develop the synchronous dual roles of CuS, which will have the extensive applications in wearable flexible E-textiles.

Automated summary

A novel PET/CuS/PPy composite electrode was developed for portable flexible solid-state supercapacitors (FSSC), exhibiting high specific capacitance and good cyclic stability, attributed to the dual functions of high electrical conductivity and large capacitance of CuS. The FSSC demonstrated superior specific capacitance and energy density, suitable for various portable devices, with promising practical applications.