Rapid preparation of nickel fluoride motif via solution-free plasma route for high-energy aqueous hybrid supercapacitor

•Solution-free, rapid yet room-temperature electrode preparation approach is utilized.•Ni foam exposed to the CF4 plasma permits the foundation of NiF2 motif nanostructure.•The NiF2 motif delivers a high capacity of 1.18 mAh/cm2 at 1 mA/cm2.•The outstanding rate capability of 84.22 % is achieved over a high current density.•Assembled hybrid capacitor delivers a high energy density of 0.96 mWh/cm2.