High performance asymmetric supercapacitor twisted from carbon fiber/MnO2 and carbon fiber/MoO3

Abstract

Fiber-shaped supercapacitors are promising energy storage devices for future flexible and portable electronics. In this study, we report a fiber-shaped asymmetric supercapacitor (ASC) device made with the metal oxides having a large work function difference, directly grown on a flexible and conductive carbon fiber (CF) substrate. Specifically, carbon fiber/MnO2 (CF/MnO2) and carbon fiber/MoO3 (CF/MoO3) were fabricated using a simple electrodeposition method. The all-solid-state fiber-shaped ASC device was then assembled with CF/MnO2 as the positive electrode and CF/MoO3 as the negative electrode. The large work function difference between the metal oxides and the high conductivity of the CF substrate provided the ASC device with remarkable performance. In particular, it exhibited capacitance of 4.86 mF cm−2 and a wide operating voltage window of 2.0 V, which resulted in an excellent energy density of 2.70 μWh cm−2 and a power density of 0.53 mW cm−2. Also, it readily tolerated 3000 cycles of electrochemical testing and extreme mechanical deformation. Consequently, the outstanding performance and stability of the fiber-shaped ASC device shows great potential for future energy storage systems.