Urea Regulating the Electrochemical Properties of Nico2o4 Microspheres

Abstract

Designing a special morphology with high porosity and prolific electro-active sites is fundamental to achieve high-performance electrode material. In this report, we prove a modified hydrothermal preparation of NiCo2O4 with various morphologies through exploiting various amount of urea as controlling agent. At optimal urea amount (0.9 g), a special morphology of urchin shaped like-microsphere is collected. Importantly, these microspheres are constituted with plentiful nanowires radiated from the centre. Interestingly, theses nanowires are constituted with attached nanodots. Owing to the special morphology with plentiful electroactive sites, NiCo2O4 based electrode material introduces eminent electrochemical characteristics in terms of excellent capacitance (1655 F·g-1 at 1 A·g-1), wonderful amount capability (78% at 30 A·g-1) and superior cycle life (95.8% in 10,000 cycles). In addition, asymmetric supercapcitor device is fabricated in aqueous electrolyte from the optimized NiCo2O4 (cathode) and active carbon (AC) (anode) delivers an energy up to 79 Wh·kg-1 with a power value of 749 W·kg-1 and conserves a superior cycling life stability of 87% (20 A·g-1) through 10,000 cycle. The actual design strategy of the NiCo2O4 urchin shaped like-microsphere proves the possibility of exploiting novel binary oxides materials with various engineering morphology behaviors as electrodes with optimized electrochemical characteristics for future energy storage.

Keywords: NiCo2O4, Controlling agent, Urchin shape-like microsphere, Supercapacitor