Heterostructured and multi-dimensional Ni-Co tellurides/NiTe with enhanced reaction kinetics for hybrid supercapacitors

A Prussian blue analogue is grown in situ on nickel foam (NF) by a co-precipitation strategy, which is further converted into Ni-Co tellurides ((Ni-Co)Te)/NiTe through a hydrothermal method. The obtained (Ni-Co)Te/NiTe shows a heterogeneous and multi-dimensional structure, which displays a high areal specific capacitance of 2390.7 mF cm−2at 1 mA cm−2and a high capacitance retention of 80.3 % after 5000 cycles. Further, a hybrid supercapacitor (HSC) is assembled by using the (Ni-Co)Te/NiTe grown on NF (NF@(Ni-Co)Te/NiTe) as the cathode and activated carbon (AC) supported on NF (NF@AC) as the anode, respectively. The HSC exhibits a maximum energy density of 95.6 Wh kg−1at the power density of 444.5 W kg−1, which is higher than most of the HSCs previously reported. The synergistic effect of the heterojunction in the (Ni-Co)Te/NiTe and its multi-dimensional structure plays a crucial role in the enhanced reaction kinetics of the HSC.