Facile Hydrothermal Synthesis and Supercapacitor Performance of Mesoporous Necklace-Type ZnCo2O4 Nanowires

In this work, mesoporous ZnCo2O4 electrode material with necklace-type nanowires was synthesized by a simple hydrothermal method using water/ethylene glycol mixed solvent and subsequent calcination treatment. The ZnCo2O4 nanowires were assembled by several tiny building blocks of nanoparticles which led to the growth of necklace-type nanowires. The as-synthesized ZnCo2O4 nanowires had porous structures with a high surface area of 25.33 m(2) g(-1) and with an average mesopore of 23.13 nm. Due to the higher surface area and mesopores, the as-prepared necklace-type ZnCo2O4 nanowires delivered a high specific capacity of 439.6 C g(-1) (1099 F g(-1)) at a current density of 1 A g(-1), decent rate performance (47.31% retention at 20 A g(-1)), and good cyclic stability (84.82 % capacity retention after 5000 cycles). Moreover, a hybrid supercapacitor was fabricated with ZnCo2O4 nanowires as a positive electrode and activated carbon (AC) as a negative electrode (ZnCo2O4 nanowires//AC), which delivered an energy density of 41.87 Wh kg(-1) at a power density of 800 W kg(-1). The high electrochemical performance and excellent stability of the necklace-type ZnCo2O4 nanowires relate to their unique architecture, high surface area, mesoporous nature, and the synergistic effect between Zn and Co metals.

Automated summary

Mesoporous ZnCo2O4 electrode material with necklace-type nanowires was synthesized by a simple hydrothermal method, exhibiting high specific capacity, decent rate performance, and good cyclic stability. The hybrid supercapacitor with ZnCo2O4 nanowires as a positive electrode showed excellent energy density at high power density. The superior electrochemical performance and stability were attributed to the unique architecture, high surface area, mesoporous nature, and synergistic effect between Zn and Co metals.