Robust rope supercapacitor constructed by programmed graphene composite fibers with high and stable performance

Abstract Scaling up energy with volume is critical for fiber supercapacitors to its practical usage in flexible and wearable electronics, which remains a pressing challenge. Here thick fiber electrodes with hierarchical pores are fabricated by programming hundreds of graphene composite fibers into a rope via scalable twisting and braiding. And a volume-independent energy density is achieved from the fiber to the rope with a tremendous volume surge of 1500 magnifications. Based on this rope, a bulky fiber supercapacitor, labeled as rope supercapacitor, is manufactured with a coaxial format. Moreover, highly integrated tandem rope supercapacitors are facilely assembled by sharing electrodes, which are strong and stable in dynamic usage. Furthermore, an 8-unit rope supercapacitor possesses a record high device energy that is 5 times and 35 times higher than that of the state-of-the-art film and fiber supercapacitors, respectively. The idea here can be extended to other fiber-shaped devices to be scaled up without any performance degrading.