Ternary ZnO/Co3O4/NiO inherited layered core-shell structure from a double template for high performanced supercapacitor

Relying on seed method, a double template ZIF-8@ZIF-67 with a layered core-shell structure was made, which is used as a sacrificial template in the next steps. After going through loading process with solvent thermal method and calcination process, ZIF-8@ZIF-67 was etched and calcined into ternary ZnO/Co3O4/ NiO successfully. Besides, benefiting from right amount of the addition of inorganic salts, the optimized ZnO/Co3O4/NiO-2 (ZCN-2) shows the outstanding performance in its morphologic structure and electrochemical performance. In the case of a current density of 1 A g(-1), the high specific capacitance of 1119.11 C g(-1) can be calculated in ZCN-2. In addition, at 10 A g(-1), the capacitance value can maintain 93.75% after experiencing 5000 cycles of charging and discharging. The maximum energy density of the assembled ZCN-2//activated carbon (AC) asymmetric supercapacitor can reach 95.82 Wh kg(-1), which is really outstanding in the present research achievements. After experiencing charge-discharge cycles with the number of 10,000 times in the case of a current density of 10 A g(-1), the cycling stability of this supercapacitor can reach 94.53% of the initial value. And after a charge, the device connected by two supercapacitors can make a light emitting diode (LED) shine up to 30 min successfully. (C) 2021 The Chinese Ceramic Society. Production and hosting by Elsevier B.V.

Automated summary

Utilizing a seed method, a double template ZIF-8@ZIF-67 with a layered core-shell structure was prepared and further transformed into ternary ZnO/Co3O4/NiO. The optimized ZnO/Co3O4/NiO-2 exhibited outstanding electrochemical performance, superior cycling stability, and high energy density.