Facile growth of homogeneous Ni(OH)2 coating on carbon nanosheets for high-performance asymmetric supercapacitor applications
in situ growth, ion-exchange reaction, hybrid Ni (OH)2, carbon nanosheet, supercapacitor
ABSTRACT The growth of a Ni(OH)2 coating on conductive carbon substrates is an efficient way to address issues related to their poor conductivity in electrochemical capacitor applications. However, the direct growth of nickel hydroxide coatings on a carbon substrate is challenging, because the surfaces of these systems are not compatible and a preoxidation treatment of the conductive carbon substrate is usually required. Herein, we present a facile preoxidation-free approach to fabricate a uniform Ni(OH)2 coating on carbon nanosheets (CNs) by an ion-exchange reaction to achieve the in situ transformation of a MgO/C composite to a Ni(OH)2/C one. The obtained Ni(OH)2/CNs hybrids possess nanosheet morphology, a large surface area (278 m2/g), and homogeneous elemental distributions. When employed as supercapacitors in a three-electrode configuration, the Ni(OH)2/CNs hybrid achieves a large capacitance of 2,218 F/g at a current density of 1.0 A/g. Moreover, asymmetric supercapacitors fabricated with the Ni(OH)2/CNs hybrid exhibit superior supercapacitive performances, with a large capacity of 198 F/g, and high energy density of 56.7 Wh/kg at a power density of 4.0 kW/kg. They show excellent cycling stability with 93% capacity retention after 10,000 cycles, making the Ni(OH)2/CNs hybrid a promising candidate for practical applications in supercapacitor devices.
Tsinghua University Press
Mingjiang Xie,Zhicheng Xu,Shuyi Duan,Zhengfang Tian,Yu Zhang,Kun Xiang,Ming Lin,Xuefeng Guo,Weiping Ding, Facile growth of homogeneous Ni(OH)2 coating on carbon nanosheets for high-performance asymmetric supercapacitor applications. NanoRes.2018, 11(1): 216–224