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

HighlightsGraphene modifications effectively improved conductivity but also resulted in a regulatory effect on the decrease in its diameter.The synergistic action of graphene and carbon fibers protected the structure of the electrode material and shortened the ion diffusion path.ReSe2@G@CNFs exerted high capacity and long cyclic stability in Na+/K+ half cells. When this compound was assembled in Na+ full cells, the cells displayed excellent performances 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 227mAhg(-1) after 500 cycles at 200mAg(-1) for Na+ storage, 230mAhg(-1) after 200 cycles at 200mAg(-1), 212mAhg(-1) after 150 cycles at 500mAg(-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 (117mAg(-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.