Hierarchical Heterojunction NiMoO ₄ /MnS Nanoarrays for High-Performance Asymmetric Supercapacitors

In this paper, the successful fabrication of NiMoO 4 /MnS composite electrodes was in situ growth on nickel foam (NF) substrates via a two-step hydrothermal methods. The in situ growth strategy effectively maintains integrity of the structure while eliminating interfacial contact resistance, significantly enhancing the material’s electrical conductivity. This structural design strategically integrates the high theoretically capacitance of NiMoO 4 with the superior conductive properties of MnS, creating abundant electrochemical active sites and synergistic effects. Consequently, the NiMoO 4 /MnS/NF electrode achieves a remarkable 9225.6 mF cm –2 areal capacitance at a current density of 4 mA cm –2, significantly surpassing the performances of individual NiMoO 4 /NF (2667.6 mF cm –2 ) and MnS/NF (492.8 mF cm –2 ) electrodes. Furthermore, the assembled asymmetric supercapacitor (ASC) device delivers a high energy density of 0.26 mWh cm –2 at a power density of 3 mW cm –2 . This study not only provides an innovative design concept for constructing heterogeneous transition metal composite materials but also establishes a scalable application foundation for developing future high-efficiency energy storage technologies.