Functionalized carbonaceous fibers for high performance flexible all-solid-state asymmetric supercapacitors

Abstract

Fiber based supercapacitors are promising energy storage devices for flexible electronics because of their integration of lightweight, high flexibility and tiny volume. Here, a facile yet effective method is developed to synthesize two types of functionalized carbonaceous fibers, i.e., carbon fiber@reduced graphene oxide@manganese dioxide (CF@RGO@MnO₂) and CF@thick RGO (CF@TRGO), by dip coating and subsequent electrochemical strategies. The assembled asymmetric supercapacitor device using CF@RGO@MnO₂ as the positive electrode and CF@TRGO as the negative electrode can be operated with a high voltage region of 1.6 V and exhibits a high volumetric energy density of 1.23 mW h cm⁻³. Additionally, our device has an excellent long-term cycling stability with more than 91% retention after 10 000 cycles. To demonstrate potential applications of our prepared fiber based all-solid-state asymmetric supercapacitors, we successfully use them to power a flexible integrated copper phthalocyanine (CuPc) photodetector and a light-emitting diode.