Uniform growth of Zn-Mn-Co ternary oxide nanoneedles for high-performance energy-storage applications

This paper reports the facile synthesis of a novel electrode material for high-performance supercapacitor. The binder-free Zn-Mn-Co ternary oxide nanoneedles with highly exposed active sites to electrolyte were examined by multiple characterizations. Zn-Mn-Co ternary oxide nanoneedle electrode exhibited a high specific capacity of 849 C g(-1) at a current density of 1 A g(-1) in three electrode measurements. Furthermore, it showed an excellent cycling stability after 8000 cycles and a very high coulombic efficiency. Moreover, hybrid supercapacitor device was assembled using Zn-Mn-Co ternary oxide nanoneedles as a positive electrode and activated carbon as a negative electrode. The hybrid supercapacitor device showed a high specific capacity of 158 C g(-1) at a current density of 1 A g(-1). The device delivered a high energy density of 35.5 W h kg(-1) and a high power density of 7.5 kW kg(-1). Interestingly, the hybrid supercapacitor device showed 100% initial capacitance retention over 7000 cycles. All these attractive results demonstrate the importance of this electrode material towards practical application.