Hydrophilically engineered polyacrylonitrile nanofiber aerogel as a soft template for large mass loading of mesoporous poly(3,4-ethylenedioxythiophene) network on a bare metal wire for high-rate wire-shaped supercapacitors

Wire-shaped solid-state supercapacitors (WSSCs) receive ever-growing interest for developing electronic textile. How to achieve a high active mass loading with a suitable mesoporous structure and strong adhesion on a bare metal wire are a severe challenge faced by the development of practical WSSCs, which must meet requirements such as high energy and power densities, fast rate capability, as well as flexibility and stability. Here, a new strategy to synthesize the wire-shaped electrode with excellent electrochemical and mechanical performances is reported using a soft aerogel template in a facile dip coating process. Hydrophilically engineered polyacrylonitrile nanofibers by adding glycerol were electrospun on a Ti metal wire to form the sacrificial aerogel template with a huge void volume, in which poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) solution was dip coated to achieve a large mass loading. The capillary effect in the subsequent natural drying process, slow dissolution of the template in a solvent, and PSS etching, together lead to a mesoporous PEDOT thick coating network formed on the metal wire with a high conductivity, strong mechanical strength and intimate interface adhesion. The resulted WSSCs based on Ti/PEDOT electrodes, exhibited a fairly wide potential window, large specific capacitance, ultrahigh rate capability and energy/power densities.