Exploration of fast ion diffusion kinetics in graphene nanoscrolls encapsulated CoSe2 as advanced anode for high-rate sodium-ion batteries

Sodium-ion batteries (SIBs) have drawn much attention due to the abundance and low cost of sodium. However, electrode materials of SIBs displayed sluggish Na+ diffusivity and fatal volume expansion, owing to the larger ionic radius of Na+ ions than Li+ ions. In this work, we built the CoSe2 nanoparticles embedded in graphene nanoscrolls (GNS) as advanced anodes for high-rate SIBs. The CoSe2/C@GNS anodes exhibited a high reversible capacity of 545 mA h g(-1) at 0.2 A g(-1). Moreover, they showed an outstanding cycling stability of 455 mA h g(-1) after 5000 cycles at 1 A g(-1), with a capacity retention of 92% calculated from 10th cycle. The CoSe2/C@GNS anode also demonstrate ultrahigh rate capabilities (212.5 mAh g(-1) at 50 A g(-1)). In addition, with a high mass loading (6 mg cm(-2)), the electrode still displayed a stable capacity (412 mA h g(-1) 1 A g(-1)). The fast electron transfer and Na+ ion diffusion kinetics creates the excellent electrochemical properties, on account of the uniform arrangement of nanoparticles and unique reticular crosslinking structure of CoSe2/C@GNS. This strategy could also be constructed other electrode materials, which provides more probabilities for the development of SIBs. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

In this study, CoSe2 nanoparticles embedded in graphene nanoscrolls were used as advanced anodes for high-rate sodium-ion batteries. The anodes exhibited high reversible capacity, outstanding cycling stability, and ultrahigh rate capabilities, showcasing the potential for development in the field of SIBs.