HIGHLIGHTS• Graphene 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.• ReSe 2 @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 ABSTRACT Rhenium diselenide (ReSe 2 ) 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, ReSe 2 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 ReSe 2 -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 ReSe 2 -carbon nanofibers benefitted from the extremely weak van der Waals interactions and large interlayer spacing of ReSe 2 , 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.