Supercapacitors have the characteristics of high power density, short charging time, long service life, and environmental friendliness, which have aroused extensive interest from researchers in many research fields. However, compared with batteries, supercapacitors have a low energy density, which limits their practical applications. From the perspective of structural design, flexible supercapacitors can be realized from three directions: one is to use an inherently elastic material as the substrate, and endow another non-elastic or poorly elastic functional material with good deformation ability; the third is Taking advantage of the device's ability to deform in different dimensional shapes, such as the bending ability of a one-dimensional fiber structure or the folding ability of a two-dimensional film, that is, if the electrodes themselves are in the form of a fiber, they are inherently light and flexible. In addition, fibrous supercapacitors can be easily integrated and woven into various electronic devices, making them naturally integrated with the textile industry and greatly promoting their practical applications.

At present, there are three basic strategies for preparing fibrous supercapacitors reported in the literature, namely: wet spinning method, dry spinning method, and hydrothermal method. It is worth noting that the above methods are not universal, and none of them can achieve micro-nano-scale structure control. Considering the general electrochemical properties of a large number of advanced nanomaterials (NMs), it is necessary to develop a general method that does not rely on some specific nanomaterials, and a deep understanding of the performance, structure optimization, and related mechanisms of fiber supercapacitors is crucial.

Recently, the research group of Dr. Zhong Jing from the Harbin Institute of Technology prepared electrode materials with extremely regular microstructures through the "dead-end filtration" method and described their properties. They mainly used the ultrafiltration process of hollow tubular membranes, which are widely used in the field of water treatment, to prepare electrode structures with precise control. In this electrode, carbon nanotubes are uniformly inserted between graphene sheets, assembled into a graphene/carbon nanotube composite electrode, assembled into a solid-state symmetric supercapacitor, which has a very high volumetric capacitance at a high scan rate, and has At a rate of 5mV/s, the volumetric specific capacitance is as high as 492 F cm-3, and the volumetric energy density of the device is ~2.7 mW h cm-3, which is three times the energy density of commercially available supercapacitors. In addition, these nanomaterials in the electrode structure exhibit a strong synergistic effect, maintaining a stable voltage plateau after 10,000 bending cycles. In addition, the structural integrity and robustness of the fiber supercapacitors are further enhanced by using solid polymer electrolytes. Their work provides new ideas for the design and control of electrode microstructures, which greatly promotes the development of small portable mobile electronic devices.

The researchers believe that this research will open a window for nanomaterial-based assembly research, provide new ideas for the design and control of electrode microstructures, and will greatly promote the development of small portable mobile electronic devices. Related papers are published online (DOI: 10.1002/Adam.).