NiFe-NiFe2O4/rGO composites: Controlled preparation and superior lithium storage properties

Binary transition-metal oxides with spinel structure have great potential as advanced anode materials for lithium-ion batteries (LIBs). Herein, NiFe-NiFe 2 O 4 / reduced graphene oxide (rGO) composites are obtained via a facile cyanometallic framework precursor strategy to improve the lithium storage performance of NiFe 2 O 4 . In the composites, NiFe-NiFe 2 O 4 nanoparticles with adjustable mass ratios of NiFe 2 O 4 to NiFe alloy are homogeneously deposited on rGO sheets. As anode material for LIBs, the optimized NiFe-NiFe 2 O 4 /rGO composite displays remarkably enhanced lithium storage performance with an initial specific capacity as high as 1362 mAh g −1 at 0.1 A g −1 and a decent capacity retention of ca . 80% after 130 cycles. Besides, the composite delivers a reversible capacity of 550 mAh g −1 at 1 A g −1 after 300 cycles. During the charge–discharge cycles, the aggregation of the NiFe-NiFe 2 O 4 nanoparticles and the structural collapse of the electrode can be well alleviated by rGO sheets. Moreover, the conductivity of the electrode can be significantly improved by the well-conductive NiFe alloy and rGO sheets. All these contribute to the improved lithium storage performance of NiFe-NiFe 2 O 4 /rGO composites.