Facile preparation of hierarchical MgCo2O4/MgCo2O4 nanochain array composites on Ni foam as advanced electrode materials for supercapacitors

Abstract

The construction and synthesis of nanoarchitectures on a cost-effective substrate with eco-friendly properties has emerged as a novel strategy for synthesizing high-performance power and energy sources. In recent years, transition ternary metal oxides (TTMOs), especially combining similar-type TTMOs, have attracted extensive attention as favorable candidates for electrode materials. Among all the well-known TTMOs, MgCo₂O₄ is a stupendous one, owing to its excellent theoretical capacitance. Electrochemical calculations indicate that composites consisting of binary MgCo₂O₄ nanoflake arrays (MCO NFAs) and MgCo₂O₄/MgCo₂O₄ nanochain arrays (MCO/MCO NCAs) exhibit a hierarchical structure with a highly altered electronic nanostructure, providing better electrical conductivity, enhanced catalytic conditions, and enhanced supercapacitive performance. Under optimized conditions, the binary MCO NFA and composite MCO/MCO NCA structures offer more active sites and charge transfer during the faradaic reaction process. Most importantly, the binary MCO NFA and MCO/MCO NCA composite electrodes show high specific capacities of ∼316.8 and 265.3 mA h g⁻¹ at a current density of 2 A g⁻¹. Interestingly, the MCO/MCO NCA composite electrode still maintained an outstanding rate capability with 97.9% of the capacity retained after 5000 cycles at a current density of 6 A g⁻¹. Therefore, the MCO/MCO NCA composite material fabricated via the combination of similar types of TTMO grown on low-cost Ni foam is certainly promising for more research and application in SCs.