Synthesis of Ni-MOF derived NiO/rGO composites as novel electrode materials for high performance supercapacitors

Ni-MOF derived NiO nanosheets growing on rGO have been successfully synthesized by a hydrothermal method following by a series of calcination procedures (300 degrees C, 400 degrees C, and 450 degrees C). The influence of the introduction of rGO and the calcination temperature on electrochemical performance of Ni-MOF derived NiO nanosheets as the electrode material were highlighted in detail. For the three-electrode test system, Ni-MOF derived NiO/rGO composites subjected to calcination at 300 degrees C demonstrated the highest specific capacitance (435.25 F.g(-1) at 1 1 A.g(-1)), and maintained 68.00% of its initial value at 8 A.g(-1). Its specific capacitance was increased by 49.34% when compared with the initial value after 25,000 cycles at 50 mV.s(-1). With the increase in calcination temperature, the specific capacitance presented the downward tendency (400 degrees C: 171.50 F.g(-1) at 1 A.g(-1), 450 degrees C: 116.00 F.g(-1) at 1 A.g(-1)) due to the reduction in specific surface area originating from the agglomeration of NiO nanosheets. The introduction of rGO greatly enhanced the electrochemical performance of the composites treated at 300 degrees C (increased by 40.40% at 1 A.g(-1) and 47.30% in specific capacitance at 8 A.g(-1)). The assembled hybrid supercapacitors (HSC) with Ni-MOF derived NiO/rGO composites (300 degrees C) and active carbon as the cathode and anode also displayed the outstanding electrochemical performance. The value of energy density reached to 76.96 Wh.kg(-1) at the power density of 400 Wh.kg(-1). All these results confirm that the MOF-derived NiO/ rGO composite should be a potential electrode material for supercapacitors.

Automated summary

Ni-MOF derived NiO nanosheets growing on rGO through a hydrothermal method followed by calcination procedures at different temperatures demonstrate excellent electrochemical performance, with the composite treated at 300 degrees C showing the highest specific capacitance and superior cycling stability.