Synthesis and Unveiling Properties of Nanocomposite NiO/Mn2O3 and Ni–Mn-Based Layered Double Hydroxide as Efficient Supercapacitor Electrodes

Abstract

The unique morphology achieved through the co-precipitation method represents a rare and notable accomplishment in the current research landscape. In this work, an exclusive sphere-like morphology of NiO/Mn₂O₃ and layered Ni–Mn–LDH (layered double hydroxide) is synthesized successfully by the conventional coprecipitation method. NiO/Mn₂O₃ and Ni–Mn–LDH are coated on stainless-steel substrates and demonstrate remarkable charge–discharge performance with significantly enhanced specific capacitance. The measured specific capacitance and retention of NiO/Mn₂O₃ is 956 F g⁻¹ and 98.4% beyond 5000 repetitions under 3 A g⁻¹. Sphere morphology enhances the charge/discharge rates through ion diffusion and reduction in diffusion distance. Such morphology supports the long-term stability of the electrode. The nickel–manganese-based LDH electrode exhibits the measured specific capacitance and retention of 905 F g⁻¹ under 1 A g⁻¹ and 94.8% at 5000 cycles at 3 A g⁻¹, respectively. Furthermore, an asymmetric supercapacitor (SC) device, fabricated using NiO/Mn₂O₃, achieves an impressive specific capacitance of 171 F g⁻¹ at 1 A g⁻¹ and exhibits a capacitance retention of 95.83% for 10 000 cycles. Due to this excellent supercapacitive performance, these materials are highly promising candidates for next-generation energy storage applications. The remarkable retention of capacitance over prolonged cycling underscores their durability, paving the way for their potential use in commercial SC devices.