ZIF-67 derived tricobalt tetroxide induced synthesis of a sandwich layered Co3O4/NiNH electrode material for high performance supercapacitors

Abstract

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.