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

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 Zn2+ 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).