Monodispersed SWNTs Assembled Coating Layer as an Alternative to Graphene with Enhanced Alkali-ion Storage Performance

Graphene coating is commonly used to improve the performance of electrode materials, while its steric hindrance effect hampers fast ion transport with compromised rate capability. Herein, a unique single-walled carbon nanotubes (SWNTs) coating layer, as an alternative to graphene, has been developed to improve the battery behavior of iron-based anodes. Benefiting from the structure merits of mesoporous SWNTs layer for fast electron/ion transport and hollow Fe3O4 for volume accommodation, as-prepared Fe3O4@SWNTs exhibited excellent lithium storage performance. It delivers a high capacity, excellent rate capability, and long lifespan with capacities of 582 mA·h·g-1 at 5 A·g-1 and 408 mA·h·g-1 at 8 A·g-1 remained after 1000 cycles. Such performance is better than graphene-coated Fe3O4 and other SWNT-Fe3O4 architectures. Besides, SWNTs coating is also used to improve the sodium and potassium storage performance of FeSe2. The kinetics analysis and ex-situ experiment further reveal the effect of SWNTs coating for fast electron/ion transfer kinetics and good structure stability, thus leading to the superior performance of SWNTs-coated composites.