Solvent-Controlled Synthesis of Zn–Co–S@Ni12P5 Arrays with Ultra-High Specific Capacitance for Hybrid Supercapacitor

The solvents used in the preparation process have a substantial influence on the structure and morphology of electrode materials, which in turn can impact the electrochemical performance for the supercapacitor. In this work, nickel foam substrate was subjected to a low-temperature phosphating reaction and then transition metal sulfides were controlled grown on the surface of Ni12P5/NF with different morphology by tuning the ratios of reaction solvents (H2O: C2H5OH). The optimized Zn–Co–S@Ni12P5/NF-1 nanosheet has an ultrahigh specific capacitance (10.7 F cm–2 at 1 mA cm–2), which originates from both the special nanosheet structure with an abundance of active sites, as well as the synergistic interaction between metal sulfides and phosphides. The assembled hybrid supercapacitor (HSC) device (Zn–Co–S@Ni12P5/NF-1//AC) has a high storage capacity (40.11 Wh/kg at 803.09 W/kg) and maintains 85.2% retention rate after 5,000 cycles. Moreover, the all-solid hybrid supercapacitors effectively lit up 9 LEDs for 2 min, which means it holds significant promise for practical energy storage applications.