Porous VN nanosheet arrays on MXene carbon fibers for flexible supercapacitors.

VN usually has poor rate performance and cycle stability. In this work, porous VN nanosheet arrays were prepared on carbon nanofibers embedded with TiCT nanosheets by electrospinning and chemical vapor deposition. The 3D network accelerates the transfer of electrons and electrolyte ions, prevents the aggregation of VN and the self-stacking of MXene, and enhances cycle stability. The solid-state flexible device comprising CoO, MXCF@VN, and KOH/PVA exhibits exceptional energy densities of 83.95 W h kg and robust cycling stability (82.8% retention after 20 000 cycles).