Nanoparticles Encapsulated in Porous Carbon Matrix Coated on Carbon Fibers: An Ultrastable Cathode for Li‐Ion Batteries

Nanostructured V 2 O 5 is emerging as a new cathode material for lithium ion batteries for its distinctly high theoretic capacity over the current commercial cathodes. The main challenges associated with nanostructured V 2 O 5 cathodes are structural degradation, instability of the solid‐electrolyte interface layer, and poor electron conductance, which lead to low capacity and rapid decay of cyclic stability. Here, a novel composite structure of V 2 O 5 nanoparticles encapsulated in 3D networked porous carbon matrix coated on carbon fibers (V 2 O 5 /3DC‐CFs) is reported that effectively addresses the mentioned problems. Remarkably, the V 2 O 5 /3DC‐CF electrode exhibits excellent overall lithium‐storage performance, including high Coulombic efficiency, excellent specific capacity, outstanding cycling stability and rate property. A reversible capacity of ≈183 mA h g −1 is obtained at a high current density of 10 C, and the battery retains 185 mA h g −1 after 5000 cycles, which shows the best cycling stability reported to date among all reported cathodes of lithium ion batteries as per the knowledge. The outstanding overall properties of the V 2 O 5 /3DC‐CF composite make it a promising cathode material of lithium ion batteries for the power‐intensive energy storage applications.