Construction of hydrangea-like nickel cobalt sulfide through efficient microwave-assisted approach for remarkable supercapacitors

[Display omitted] •The growth mechanism of nickel cobalt sulfide (NCS) by microwave-assisted approach is supposed to be oriented attachment.•NCS synthesis period could be shortened to current minutes range through microwave-assisted approach.•NCS displays superior capacity, rate and cycling properties due to the special self-assembling hydrangea-like nanostructure.•The NCS20//AC supercapacitor basically sustains steady electrochemical performance ranging from 0 to 60 °C. The growth mechanism of ternary nickel cobalt sulfide (denoted as NCS) synthesized by microwave-assisted process is a vital component factor for tailoring physical or chemical properties and acquiring outstanding electrochemical performance, but it is still vague up till now. Herein, by virtue of time-controlled process of microwave-assisted method, the NCS growth mechanism has been researched and supposed to be oriented attachment. Moreover, due to the control of synthesis time, various structured (such as nanoparticles, nanosheet, hydrangea-like) NCS have been constructed. Integrated with high porosity, imperfect nanosheets and self-assembling hydrangea-like structure, the optimal NCS displays the supreme capacity of 226.5 mAh g−1 at a current density of 1 A g−1, and retains 86.1%, 71.9% capacitance retention as the current density increases to 20, 40 A g−1, respectively. To verify practical application performance, a hybrid NCS//activated carbon asymmetric supercapacitor has been assembled. Notably, it could deliver both high energy density and excellent cycling stability (i.e., 98.7% capacitance retention after 50 000 cycles). This work clarifies a possible growth mechanism of NCS and offers a speedy strategy to fabricate novel electrode materials by microwave-assisted process.