High-rate sodium storage performance enabled using hollow Co3O4 nanoparticles anchored in porous carbon nanofibers anode

Transition metal oxides with high theoretical specific capacity, when used as anode materials in sodium-ion batteries, usually suffer from poor structural stability and inferior rate capacity. The use of hollow nanostructured metal oxides incorporated into porous carbon frameworks is a promising strategy for addressing this issue. Herein, we fabricated hollow Co3O4 nanoparticles anchored in a porous carbon nanofiber matrix (Co3O4@PCNF) by electrospinning, metal-organic framework incorporation, and two-step calcination. The porous carbon nanofiber matrix can facilitate structural stability and provide multiple channels for fast electron/ion transport. The hollow Co3O4 nanoparticles resulting from the Kirkendall effect can shorten the Na-ion transport path for achieving fast reaction kinetics. The Co3O4@PCNF exhibits a reversible specific capacity of 487 mAh g(-1) at 0.05 A g(-1) with a high initial Coulombic efficiency of 91.6%, outstanding rate performance (220 mAh g(-1) at 5 A g(-1)), and stable cycling, thereby making it suitable as an anode for sodium-ion batteries. Moreover, a full cell fabricated using a Co3O4 @PCNF anode and Na3V2(PO4)(2)O2F cathode delivers a reversible capacity of 205 mAh g(-1) at 0.5 A g(-1). We believe that our approach can provide a design pathway to improve the performance of Co3O4-based anodes for sodium-ion batteries and offer a new strategy to produce hollow-structure electrode materials for other energy-storage devices. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

In this study, hollow Co3O4 nanoparticles anchored in a porous carbon nanofiber matrix were successfully synthesized, showing improved performance as an anode material for sodium-ion batteries, including high specific capacity, outstanding rate performance, and stable cycling. The design strategy offers a new pathway to enhance the performance of Co3O4-based anodes and produce hollow-structure electrode materials for various energy storage devices.