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‐NiFe2O4/ reduced graphene oxide (rGO) composites are obtained via a facile cyanometallic framework precursor strategy to improve the lithium storage performance of NiFe2O4. In the composites, NiFe‐NiFe2O4 nanoparticles with adjustable mass ratios of NiFe2O4 to NiFe alloy are homogeneously deposited on rGO sheets. As anode material for LIBs, the optimized NiFe‐NiFe2O4/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‐NiFe2O4 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‐NiFe2O4/rGO composites. NiFe‐NiFe2O4/rGOcomposites with NiFe‐NiFe2O4 nanoparticles homogeneouslydeposited on reduced graphene oxide (rGO) sheets are prepared via in‐situ growth of Ni[Fe(CN)5NO]·xH2O nanoparticles on grapheneoxide (GO) sheets followed by a two‐step thermal treatment, and the optimized NiFe‐NiFe2O4/rGOcomposite displays remarkably enhanced lithium storageperformance.