Rational design of graphene-encapsulated NiCo2O4 core-shell nanostructures as an anode material for sodium-ion batteries

Abstract Sodium-ion batteries (SIBs) have gained more and more interest for grid-level energy storage applications compared with current lithium-ion batteries (LIBs). In this paper, well-uniform and dispersed spindle-shaped NiCo 2 O 4 particles were synthesized by solvothermal method, and then graphene-encapsulated NiCo 2 O 4 (NiCo 2 O 4 @G) was formed core-shell nanostructures, which greatly enhanced the electronic and ionic (electro-active) conduction and also effectively buffering to accommodate the strain. Benefit from its structure feature, the prepared NiCo 2 O 4 @G core-shell nanostructures composite shows good cycling with a capacity of up to ∼400 mAh g −1 (100 mA g −1 ) in 100 cycles for NIBs anode. The facile synthesis process and excellent SIBs behaviors in this paper are expected to be extended in developing other anode materials in battery system.