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 poly vinylpyrrolidone/po-lyacry lonitrile（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.