Carbon dots integrated into nickel-cobalt hydroxide as superior electrode for supercapattery

Abstract

Nickel hydroxide (Ni(OH)2) is one of the most valuable electrode materials for supercapacitors. Owing to the low stability and conductivity of Ni(OH)2 electrode, the preparation of a fast and high-stability Ni(OH)2 electrode is a significant challenge. Nickel hydroxide integrated with cobalt and carbon dots (CDs-Co/Ni(OH)2) as a high performance electrode has been prepared by cathodic electrodeposition for supercapattery in this work. Compared with unintegrated Ni(OH)2 electrode or carbon dots integrated Ni(OH)2 electrode, the introduction of Co greatly improves the stability of the Ni(OH)2 electrode, particularly at high current density. The as-obtained CDs-Co/Ni(OH)2 electrode presents a high specific capacitance of 338.6 mAh/g at 5 A/g and an extraordinary cycling stability with 1000 cycles even under a high current density of 40 A/g (retaining 84.6%). Besides, the CDs-Co/Ni(OH)2 electrode exhibits an energy density of 281.2 Wh/kg at a power density of 57.2 kW/kg. Such a glorious stable CDs-Co/Ni(OH)2 electrode may provide significant insight into future multifarious electronics and electrified vehicle applications.