Exploring the electrochemical synergy of Ni₃S₄/siloxene composite as supercapacitor electrode

The construction of heterostructures is a promising strategy to enhance charge transfer efficiency in electrode materials, however, achieving precise control over interfacial interactions within two-dimensional lamellar hosts remains challenging. Siloxene with two-dimensional lamellar structure was synthesized via the topological transformation of calcium disilicide precursor. Ni₃S₄ nanoparticles were then anchored between the interlayers of siloxene skeleton through the solvothermal method. The effect of solvothermal time on the morphology and electrical properties of Ni₃S₄/siloxene composite was investigated in detail. The composite obtained with the optimal solvothermal time of 9 h (NS-9) effectively inhibits the restacking of siloxene layers, thereby facilitating electron and ion transport and providing a larger contact area and more active sites for redox reactions. The synergistic effect between Ni₃S₄ and siloxene enhances the electron density within the heterostructure and significantly enhances the electron transfer efficiency compared to the individual components. The resulting Ni₃S₄/siloxene electrode displays outstanding electrochemical performance, achieving a specific capacitance of 1090 F g^-1 at the current density of 0.5 A g^-1. Additionally, the assembled NS-9//AC asymmetric supercapacitor delivers 37.1 Wh kg^-1 energy density at the power density of 801.1 W kg^-1. Therefore, the Ni₃S₄/siloxene heterostructure is demonstrated to be a promising electrode material for advanced energy storage applications.