Flexible Asymmetric Threadlike Supercapacitors Based on NiCo2Se4 Nanosheet and NiCo2O4/Polypyrrole Electrodes

Flexible threadlike supercapacitors with improved performance are needed for many wearable electronics applications. Here, we report a high performance flexible asymmetric all-solid-state threadlike supercapacitor with a NiCo2Se4 positive electrode and a NiCo2O4@PPy (PPy: polypyrrole) negative electrode. The as-prepared electrodes display outstanding volume specific capacitance (14.2Fcm(-3)) and excellent cycling performance (94% retention after 5000cycles at 0.6mA) owing to their nanosheet and nanosphere structures. The asymmetric all-solid-state threadlike supercapacitor expanded the stability voltage window from 0-1.0V to 0-1.7V and exhibits high volume energy density (5.18mWhcm(-3)) and superior flexibility under different bending conditions. This study provides a scalable method for fabricating high performance flexible supercapacitors from easily available materials for use in wearable and portable electronics.