Experimental and theoretical investigation of a mesoporous NiCo2O4/rGO nanosheet network as a high-performance anode for lithium-ion batteries

Abstract

The layered structures of graphene and reduced graphene oxide (rGO) can enable synergetic binary systems with transition metal oxides, making them promising candidates for high-rate lithium-ion batteries (LIBs). In this study, an NiCo₂O₄/rGO nanosheet network was synthesized using a one-pot hydrothermal method followed by calcination. The results of this study demonstrate that the hybrid structure possessed a higher specific surface area (∼121 m² g⁻¹) than pristine NiCo₂O₄ (∼77 m² g⁻¹). Density functional theory (DFT) calculations and electrochemical impedance spectroscopy (EIS) confirmed the enhanced kinetics of the NiCo₂O₄/rGO nanosheet network, making it highly suitable for lithium storage. The developed electrode delivered an initial discharge capacity of ∼1760 mAh g⁻¹ at 50 mA g⁻¹ and exhibited an excellent reversible capacity of ∼867 mAh g⁻¹ at 300 mA g⁻¹ after 100 cycles, with a coulombic efficiency of 86%. Furthermore, the electrode demonstrated outstanding cyclic stability, retaining ∼97% of its capacity after 800 cycles. This significantly improved performance was attributed to the synergistic effects of NiCo₂O₄ and rGO, as well as the enhanced charge-transfer kinetics. These findings suggest that NiCo₂O₄/rGO hybrid structures can play a vital role in the development of efficient and sustainable energy-storage solutions.