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.

In this paper, we propose a stochastic ratio-dependent one-predator and two-mutualistic-preys model perturbed by white and telegraph noise. By the M-matrix analysis and Lyapunov functions, sufficient conditions of stochastic permanence and extinction are established. These conditions are all dependent on the parameters of subsystems and the stationary probability distribution of the Markov chain. We also obtain the boundary of limit superior and inferior of the average in time of the solution under stochastic permanence. Finally, we give two examples and numerical simulations to illustrate main results.

Using molecular dynamics, nudged elastic band and modified analytic embedded atom methods, the self-diffusion dynamics properties of palladium atomic clusters up to seven atoms on the Pd (1 1 1) surface have been studied at temperatures ranging from 300 to 1000 K. The simulation time varies from 20 to 75 ns according to the cluster sizes and the temperature ranges. The heptamer and trimer are more stable than the other neighboring clusters. The diffusion coefficients of the clusters are derived from the mean square displacement of the cluster's mass-center, and the diffusion prefactors D 0 and activation energies E a are derived from the Arrhenius relation. The activation energy of the clusters increases with the increasing atom number in the clusters, especially for Pd 6 to Pd 7 . The analysis of trajectories shows the noncompact clusters diffuse by the local diffusion mechanism but the compact clusters diffuse mainly by the whole gliding mechanism, and some static energy barriers of the diffusion modes are calculated. From Pd 2 to Pd 6 , the prefactors are in the range of the standard value 10 −3 cm 2 s −1 , and the prefactor of Pd 7 cluster is 2 orders of magnitude greater than that of the single Pd adatom because of a large number of nonequivalent diffusion processes. The heptamer can be the nucleus in the room temperature range according to nucleation theory.

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