Optimization of NiFe₂O₄/rGO composite electrode for lithium-ion batteries

Graphical abstract: A NiFe₂O₄/rGO composite wasfabricated via a hydrothermal-annealing method, in which the mean size of spinel NiFe₂O₄ nanoparticles was around 20 nm. The optimized NiFe₂O₄/rGO electrode with CMC binder exhibited high reversible capacity, good cycling durability and high-rate capability, whereas the electrode with PVDF binder underwent rapid capacity decay. - Highlights: • The rGO content in NiFe₂O₄/rGO composites was optimized. • Proper choice of binders to improve lithium-storage performance was first compared. • The NiFe₂O₄/rGO-CMC binder presented better lithium-storage performance. • The NiFe₂O₄/rGO-CMC binder showed a capacity of 1105 mAh g⁻¹ after 50 cycles. • The NiFe₂O₄/rGO-CMC binder possessed good rate capability of 439 mAh g⁻¹ at 5 A g⁻¹. - Abstract: The combination of carbon compositing and the proper choice of binders in one system offer an effective strategy for improving electrode performance for lithium ion batteries (LIBs). Here, we focus on the optimization of reduced graphene oxide content in NiFe₂O₄/reduced graphene oxide (abbreviated to NiFe₂O₄/rGO) composites and the proper choice of binders to enhance the cycling stability of the NiFe₂O₄ electrode. The NiFe₂O₄/rGO composites were fabricated by a hydrothermal-annealing method, in which the mean size of spinel NiFe₂O₄ nanoparticles was approximately 20 nm. When tested as anode materials for LIBs, the NiFe₂O₄/rGO electrodes with carboxymethylcellulose (CMC) binder exhibited excellent lithium-storage performance including high reversible capacity, good cycling durability and high-rate capability. The capacity could be retained as high as 1105 mAh g⁻¹ at a current density of 100 mA g⁻¹ for over 50 cycles, even cycled at higher current density of 1000 mA g⁻¹, a capacity of 800 mAh g⁻¹can be obtained, whereas the electrode with the polyvinylidene fluoride (PVDF) binder suffered from rapid capacity decay under the same test conditions. As a result, the NiFe₂O₄/rGO composites with CMC binder electrode in this work are promising as anodes for high-performance LIBs, resulting from the synergistic effect of optimal graphene content and proper choice of binder.