Self-assembly of a NiO@NiFe2O4/rGO architecture for stable and ultra-long-life lithium-ion storage

Abstract

NiFe₂O₄, as an anode material for lithium-ion batteries, has attracted extensive attention due to its high theoretical capacity. However, its practical application is greatly restricted due to the serious volume expansion that occurs during electrochemical reactions. A novel NiO@NiFe₂O₄/reduced graphene oxide (rGO) architecture was self-assembled by using a facile hydrothermal method and annealing treatment, and its electrochemical lithium-ion storage performance was studied. The results indicate that the NiO@NiFe₂O₄/rGO electrode exhibits superior rate capability and cycling performance, with a high specific capacity of 930.12 mA h g⁻¹ at 0.1 A g⁻¹ after 100 cycles and 663.72 mA h g⁻¹ at 0.5 A g⁻¹ after 300 cycles. In addition, it still delivers large specific capacities of 342.6 and 213.55 mA h g⁻¹ after 1000 cycles with a coulombic efficiency of more than 99% at high current densities of 2 and 5 A g⁻¹, respectively. This distinguished electrochemical performance is ascribed to the unique and stable structure of the self-assembled NiO@NiFe₂O₄/rGO electrode material and the synergistic effect between NiO, NiFe₂O₄ and rGO. This work provides the possibility of improving the lithium-ion storage capacity of transition metal oxides by the facile self-assembly construction of an electrode material architecture.