Stabilizing V2O3 in carbon nanofiber flexible films for ultrastable potassium storage

Abstract

Herein, we designed and synthesized carbon nanofiber flexible films with ultrafine V₂O₃ nanocrystals uniformly dispersed in the skeleton of nanofibers (denoted as V₂O₃/CNF). In this structure, the oxygen-bridged (V–O–C) bonds grafted on the inner surface of nanopores in the carbon nanofibers provide abundant exposed electrochemically active sites as well as effectively avoiding the agglomeration of V₂O₃ nanocrystals to induce volume expansion. Besides, the flexible carbon matrix with porous interconnected channels facilitates the fast transfer of the K⁺-containing electrolyte and electrons generated in the electrochemical reactions. V₂O₃/CNF films with unique structural characteristics deliver a good potassium-storage performance with an outstanding cycling stability (retention of 98% after 2500 cycles at 1 A g⁻¹) and excellent rate capacity (175 mA h g⁻¹ at 10 A g⁻¹), and the DFT results prove the superiority of V–O–C bonds.