Improved Na+/K+ Storage Properties of ReSe2–Carbon Nanofibers Based on Graphene Modifications

Abstract

Abstract Rhenium diselenide (ReSe2) has caused considerable concerns in the field of energy storage because the compound and its composites still suffer from low specific capacity and inferior cyclic stability. In this study, ReSe2 nanoparticles encapsulated in carbon nanofibers were synthesized successfully with simple electrospinning and heat treatment. It was found that graphene modifications could affect considerably the microstructure and electrochemical properties of ReSe2–carbon nanofibers. Accordingly, the modified compound maintained a capacity of 227 mAh g−1 after 500 cycles at 200 mA g−1 for Na+ storage, 230 mAh g−1 after 200 cycles at 200 mA g−1, 212 mAh g−1 after 150 cycles at 500 mA g−1 for K+ storage, which corresponded to the capacity retention ratios of 89%, 97%, and 86%, respectively. Even in Na+ full cells, its capacity was maintained to 82% after 200 cycles at 1C (117 mA g−1). The superior stability of ReSe2–carbon nanofibers benefitted from the extremely weak van der Waals interactions and large interlayer spacing of ReSe2, in association with the role of graphene-modified carbon nanofibers, in terms of the shortening of electron/ion transport paths and the improvement of structural support. This study may provide a new route for a broadened range of applications of other rhenium-based compounds.

Keywords

• Rhenium diselenide
• Carbon nanofiber
• Graphene
• Sodium-/potassium-ion batteries
• Full cell