Stabilizing V2O3 in carbon nanofiber flexible films for ultrastable potassium storage

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.

Automated summary

In this study, carbon nanofiber flexible films with ultrafine V2O3 nanocrystals uniformly dispersed in the skeleton of nanofibers (V2O3/CNF) were designed and synthesized. The films exhibited excellent potassium storage performance, with outstanding cycling stability (98% retention after 2500 cycles at 1 A g(-1)) and excellent rate capacity (175 mA h g(-1) at 10 A g(-1)). The presence of oxygen-bridged (V-O-C) bonds in the carbon nanofibers provided abundant electrochemically active sites and effectively prevented agglomeration-induced volume expansion.