NiFe2V2O8@N-Doped carbon Yolk-Double shell spheres for efficient lithium storage

Polymetallic oxide nanostructures with intricate architectures have become the promising subject of much recent investigations into high-efficiency electrode materials for lithium-ion batteries (LIBs). However, their smooth implementation is still plagued by the fabrication of multi-component structures as well as the delivered inadequate specific capacities. Here, complex NiFe2V2O8@N-doped carbon nanostructures with hierarchically porous yolk-double shell spherical architectures via a facile template-free approach are developed and evaluated as the high-efficiency anode materials for LIBs. Benefited from the yolk-double shell constructions, impressively, the electrode harvests a high reversible capacity of 1347.6 mA h g−1 over 200 cycles without visible deterioration at 0.2 A g−1, a robust rate capability (726.1 mA h g−1 at 5 A g−1), and a desirable cycle stability (75.6% capacity retention over 300 cycles at 1 A g−1). Such excellent electrochemical Li-ion storage capability is believed to result from the fast ion-diffusion kinetics enabled by the synergetic cation and oxygen redox because of the introduction of vanadium redox couples, which can be further boosted by capacitive-dominated surface electrochemical reaction. This work provides enlightening insights into the elaborate design and fabrication of complex porous yolk-shell-like nanostructures with intricate compositions for high-efficiency lithium storage.