PVP/PAN‐derived porous carbon fiber for zinc‐ion hybrid supercapacitors

Abstract Porous carbon fibers are promising cathodes for zinc‐ion hybrid supercapacitors (ZHSs) owing to their abundant active sites, great conductivity, and stable physical and chemical properties. However, designing a proper preparation technique to regulate the microstructure of carbon fibers still remains a great challenge. Here, a polyvinylpyrrolidone/po‐lyacrylonitrile (PVP/PAN)‐derived porous carbon fiber is developed via the PVP/PAN blend electrospinning and hydrothermal selective PVP removal strategy. The hydrothermal selective PVP removal strategy can effectively avoid a cross‐linking between PVP and PAN during the traditional stabilization at air atmosphere. In PVP/PAN‐derived porous carbon fiber, the sufficient micropores provide abundant space for the Zn 2+ storage, whereas the proper mesopores contribute to the fast ion transfer. These hierarchical porous structures endow ZHSs with high specific capacity and high‐rate performance. The ZHS assembled with the optimal PVP/PAN‐derived porous carbon fiber (PVP‐PANC‐0.8) displays an outstanding specific capacity of 208 mAh·g −1 , high rate capability (49.5%) from 0.5 to 5 A·g −1 , and 72.25% capacity retention after 10,000 cycles at 0.5 A·g −1 .