ZIF-67 Derived Tricobalt tetroxide Induced Synthesis of Sandwich Layered Co3O4/NiNH Electrode Material for High Performance Supercapacitors

Novel sandwich layered Co3O4/NiNH was synthesized as a high-performance electrode for supercapacitors under hydrothermal conditions. ZIF-67 derived rhombic dodecahedral Co3O4 broke into fine Co3O4 particles, inducing the growth and self-assembly of Ni3(NO3)2(OH)4 nanosheets to form sandwich layered Co3O4/NiNH. Meanwhile, oxygen vacancies were generated on the surface of Co3O4/NiNH. The sandwich layered structure and oxygen vacancies can effectively improve the charge and ion transfer at the Co3O4/NiNH electrode/electrolyte interface. The Co3O4/NiNH electrode exhibited a maximum specific capacity of 583 C g−1 at 1 A g−1. An asymmetric supercapacitor was assembled with Co3O4/NiNH as the positive electrode and active carbon as the negative electrode. The assembled device showed a high energy density of 42.6 W h kg−1 at a power density of 823 W kg−1. A stability test was conducted to evaluate the assembled device. After 10 000 cycles, the capacitor retention rate was 82.3%, indicating that the Co3O4/NiNH//AC device had excellent cycle stability. Co3O4/NiNH is a promising electrode material for commercial applications.