Confined growth of Fe2O3 nanoparticles by holey graphene for enhanced sodium-ion storage

Metal oxide/graphene hybrids are promising anode materials for sodium-ion batteries (SIBs). However, avoiding the overgrowth of the metal oxide nanoparticles (NPs) with high content and eliminating the blocking effect of graphene towards ion diffusion are still hard to achieve, lowering the active material utilization. Herein, we prepare a Fe2O3/holey graphene (FHG) anode for SIBs with enhanced electro-chemical performance. The introduced hole edges and functional groups in holey graphene help adsorb Fe3+ and anchor the formed NPs to avoid their aggregation through the formation of Fe-O-C bonds, effectively confining the growth of Fe2O3 NPs and enhance their electrochemical activity. Besides, the holes on graphene facilitate the ion-transport to enhance the utilization of Fe2O3 and decrease the ion-diffusion resistance. As a result, FHG shows the uniformly distributed NPs with around 30 nm with a high Fe2O3 content of similar to 73 wt%, and thus, the improved reversible capacity (923 mAh g(-1) at 0.1 A g(-1)) and rate capability (318 mAh g(-1) at 2 A g(-1)), much better than the Fe2O3/graphene hybrid without holes. This work demonstrates an effective method to improve the utilization and reaction kinetics of metal oxide, which can be extended to prepare the other hybrid materials for different applications. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The Fe2O3/holey graphene (FHG) anode prepared in this study demonstrates enhanced electro-chemical performance by adsorbing Fe3+ and anchoring NPs to avoid aggregation, effectively confining the growth of Fe2O3 NPs and enhancing their electrochemical activity.