High performance symmetric supercapacitor based on zinc hydroxychloride nanosheets and 3D graphene-nickel foam composite

In this work, zinc hydroxychloride nanosheets (ZHCNs) were deposited on 3d graphene-nickel foam (NiF-G) by employing a simple hydrothermal synthesis method to form NiF-G/ZHCNs composite electrode materials. The fabricated NiF-G/ZHCNs electrode revealed a well-developed pore structures with high specific surface area of 119 m 2  g −1 , and used as electrode materials for symmetric supercapacitor with aqueous alkaline electrolyte. The specific areal capacitance and electron charge transfer resistance (R ct ) were 222 mF cm −2 (at current density of 1.0 mA cm −2 ) and 1.63 Ω, respectively, in a symmetric two-electrode system. After 5000 cycles with galvanostatic charge/discharge, the device can maintain 96% of its initial capacitance under 1.0 mA cm −2 and showed low R ct of about 9.84 Ω. These results indicate that NiF-G/ZHCNs composite is an excellent electrode material for electrochemical energy storage devices.