Activated carbon fibers with manganese dioxide coating for flexible fiber supercapacitors with high capacitive performance

Fiber supercapacitor (FSC) is a promising power source for wearable/stretchable electronics and high capacitive performance of FSCs is highly desirable for practice flexible applications. Here, we report a composite of manganese dioxide (MnO2) and activated carbon fibers (ACFs) with high MnO2 mass loading and microporous structure (abbreviated as MnO2@ACF), which is used as a fiber electrode to produce a FSC with a high capacitive performance and a good flexibility. The MnO2@ACF composite electrode in FSCs delivers an ultrahigh specific capacitance of 410 mF/cm2 at 0.1 mA/cm2, corresponding to a high energy density of 36 µWh/cm2 and high power density of 726 µW/cm2. Such high capacitive performance and simple fabrication method indicates that the MnO2@ACF composite is a very promising electrode material for flexible fiber supercapacitors.