Two‐Step Deposition/Reduction Synthesis of Porous Lamellar β‐Ni(OH) 2 /Reduced Graphene Oxide Composites with Large Capacitance for Supercapacitors

Ni(OH) 2 /RGO composite are synthesized though a facile two‐step method, in which the Ni(OH) 2 deposition and GO reduction processes take place separately. The present methods promote the deposition of more Ni(OH) 2 and full utilization of RGO, owing to the high reactivity, good solubility, and dispersity of GO. Moreover, the utilization of additives is avoided. The Ni(OH) 2 /RGO synthesized by using the two‐step method shows a uniform porous lamellar structure with a high specific surface area. When employed as a supercapacitor electrode material, the Ni(OH) 2 /RGO composite exhibits a high specific capacitance of 2877 F g −1 , long cycle life with capacitance retention of 86.5 % after 4000 cycles, and high energy density of 120.9 Wh kg −1 at a power density of 0.14 kW kg −1 . The Ni(OH) 2 /RGO composite prepared by using the two‐step method in this work shows 11.8–85.1 % higher specific capacitances than composites fabricated by using the other method. The excellent performances and the facile synthesis method highlight the promising potential of the present Ni(OH) 2 /RGO composite in supercapacitor applications.