Developing stable and high-capacity Al₂O₃ incorporated MoS₂ electrode materials for supercapacitor applications: A high ion-diffusion phenomena

Supercapacitors are highly recognized as promising energy storage devices due to their rapid charge-discharge responses, exceptional power density, and long-term stability. Nonetheless, their relatively low energy density and limited specific capacitance (C_sp) present challenges for wider application. To address these limitations, this study investigates the development of aluminium oxide (Al₂O₃) incorporated molybdenum disulphide (MoS₂) nanocomposites with varying Al₂O₃ content (5, 10, and 15 wt%), and designated as AM-5, AM-10, and AM-15. The inclusion of Al₂O₃ enhances the structural integrity and electrochemical performance by creating a more favourable path for ion transport and storage. Among the nanocomposites, AM-10 exhibits superior electrochemical performance, achieving a high discharge specific capacitance (C_dsp) of 509.42 F/g at 0.5 A/g, attributed to the synergistic effect from an optimal balance between Al₂O₃ and MoS₂. The charge storage mechanism appears to be ion-diffusion controlled, as indicated by a b value is 0.493, which is less than 0.5, suggesting effective ion intercalation. Long-term stability tests based on galvanostatic charge-discharge, revealed that AM-10 retains 78.5 % and 80 % of its C_dsp after 1500 and 4000 cycles at 1 and 5 A/g, respectively. Furthermore, its lower resonant frequency (0.204 Hz) suggests prolong ion interaction with active sites, further contributing to its enhanced performance. These findings demonstrate the enormous potential of the AM-10 nanocomposite as a high-performance electrode candidate for supercapacitor application.