CuS/polyaniline nanoarray electrodes for application in high-performance flexible supercapacitors

It is imperative to design and fabricate a high-performance free-standing electrode to meet the demand for flexible energy-storage devices with the development of wearable and portable electronics. CuS is an impressive candidate as an ideal pseudo-capacitance material due to its high theoretical capacity, easy preparation and wide source of raw materials. However, the low conductivity of CuS limits its application. Herein, polyaniline (PANI) was coated on CuS @ functional carbon cloth (fCC) to address the inherent defects of CuS using a facile polymerization procedure. Nano-scale PANI arrays with excellent conductivity grown on super-hydrophilic fCC provide a superior electroactive surface and facilitate electron transfer and electrolyte diffusion, which enhance the electrochemical performance of free-standing electrode. The as-prepared PANI/CuS@fCC electrode exhibits outstanding areal capacitance of 2167.2 mF cm −2 at 0.5 mA cm −2 , impressive capacitance retention rate (89.2 %) after 5000 cycles at 5 mA cm −2 , and satisfactory mechanical properties and flexibility. The assembled symmetrical supercapacitor also exhibits significant rate capacity with a specific capacitance of 816.4 mF cm −2 , a high energy density of 0.268 mW h cm −2 at 0.5 mW cm −2 and stable cycle performance with a capacitance retention rate exceeding 98 %. This study provides an effective strategy to fabricate advanced and flexible supercapacitor electrode. • A flexible PANI/CuS@fCC electrode was prepared by a facile solution polymerization. • The cooperation of PANI nanoarrays and CuS endows the electrode excellent electrochemical activity. • The electrode demonstrates a capacitance of 2167.2 mF cm −2 , power density of 3867.7 μW cm −2 at 0.5 mA cm −2 . • The electrode exhibits satisfactory mechanical properties and flexibility.