Hydrothermal synthesis of Cu-doped CoS2@NF as high performance binder free electrode material for supercapacitors applications

In current work, we are reporting the synthesis of pure and Cu doped CoS 2 nanoparticles on Nickel foam by one step hydrothermal method. The physiochemical properties of Cu.CoS 2 in comparison to pure CoS 2 were studied with the help of XRD, FT-IR, SEM, EDX and I–V measurements. Cubic phase structure of CoS 2 and Cu.CoS 2 was confirmed by XRD data. Characteristics FT-IR vibrational bands revealed the presence of Co–S bonds. SEM micrographs showed cottony spherical particles of CoS 2 and Cu.CoS 2 with some degree of aggregation. Ohmic contacts were formed in CoS 2 after doping with Cu ions, which enhanced the conductivity of Cu.CoS 2 to 3.39 × 10 −3 Sm −1 , as compared to 8.26 × 10 −6 Sm −1 for pure CoS 2 . When investigated for electrochemical performance, as fabricated binder free Cu.CoS 2 showed outstanding supercapacitive performance with specific capacitance of 503 Fg -1 at 1 Ag -1 . Additionally, Cu.CoS 2 exhibited great cyclic stability with 91.1% capacity retention at 9 Ag -1 after 3000 cycles. Remarkable specific capacitance, rate capability and cyclic stability of Cu doped CoS 2 can be accredited to its unique self-supporting design, morphological contributions, high conductivity and reduced grain size. Consequently, Cu.CoS 2 @NF electrode can act as promising candidate for energy storage applications.