Tailoring Mo-Doped NiCoP Grown on (Ni,Co)Se₂ Nanoarrays for Asymmetric Supercapacitor with Enhanced Electrochemical Performance

Both composition and nanostructure play vital roles in the electrochemical properties of the transition-metal compounds. Rational elemental doping and nanostructure design could accelerate the Faradaic redox reaction kinetics and increase the electroactive sites. Herein, we have successfully synthesized core–shell structure nanoarrays where (Ni,Co)Se2 nanowires directly grow on activated carbon cloth as the conductive core to support an Mo-doped NiCoP nanosheet shell. This hierarchical nanoarray electrode exhibits a high areal capacity of 1.99 C/cm2 at 2 mA/cm2 (a gravimetric specific capacity of 797 C/g) and notable rate capability (1.54 C/cm2 at 50 mA/cm2). The asymmetric supercapacitor device assembled using (Ni,Co)Se2@Mo-NiCoP as the cathode and activated carbon as the anode exhibits a high energy density of 33.7 Wh/kg at a power density of 800 W/kg.