Carbon‐Encapsulated Tube‐Wire Co3O4/MnO2 Heterostructure Nanofibers as Anode Material for Sodium‐Ion Batteries

Abstract This study presents a general approach for the synthesis of carbon‐encapsulated wire‐in‐tube Co 3 O 4 /MnO 2 heterostructure nanofibers (Co 3 O 4 /MnO 2 @C) via electrospinning followed by calcination. The as‐synthesized Co 3 O 4 /MnO 2 @C is investigated as the sodium‐ion batteries anode material, which not only exhibits a high reversible capacity of 306 mAh g −1 at 100 mA g −1 over 200 cycles, but also shows a cycling stability of 126 mAh g −1 after 1000 cycles at a high current density of 800 mA g −1 . The excellent electrochemical performance can be ascribed to the contribution from carbon‐encapsulated outer‐tube Co 3 O 4 and inner‐wire MnO 2 heterostructures, which offer a large internal space and good electrical conductivity. The present work can be helpful in providing new insights into heterostructures for sodium‐ion batteries and other applications.