Experimental and theoretical insights of binder-free magnesium nickel cobalt selenide star-like nanostructure as electrode

In recent progress of electrode development, transition metal selenides have drawn great attention in supercapacitors. Their admirable properties have been exhibited through superior electrochemical performance, lower cost, and environmental friendliness. For the first time, we successfully demonstrate the structural orientation of ternary Mg-Ni-Co selenide (MNCSe) by fine-tuning of solvothermal reaction temperature. Self-alignment MNCSe nanoflakes facilitates the electrochemical performance by providing porous channels and large specific area. The self-aligned star-like MNCSe-180 nanoflakes can deliver a high specific capacity of 299.16 mAh g-1 (1 A g-1) in an aqueous KOH electrolyte. Moreover, a hybrid supercapacitor device provides a high energy density of 46.56 Wh kg-1 and a maximum power density of 5.9 kW kg-1. Hence, the presented electrode design holds great promise in material synthesis and this work also provides a deep understanding of the charge-storage process of novel materials capable of capacitive properties for next-generation energy storage devices.

Automated summary

Transition metal selenides have become a popular choice in supercapacitors due to their excellent electrochemical performance, low cost, and environmentally friendly nature. Through fine-tuning the solvothermal reaction temperature, the structural orientation of ternary Mg-Ni-Co selenide (MNCSe) was successfully demonstrated. The self-aligned star-like MNCSe-180 nanoflakes showed a high specific capacity of 299.16 mAh g-1 (1 A g-1) in an aqueous KOH electrolyte. A hybrid supercapacitor device based on this electrode design achieved a high energy density of 46.56 Wh kg-1 and a maximum power density of 5.9 kW kg-1. This work provides valuable insights for the synthesis of novel materials with capacitive properties in next-generation energy storage devices.