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

Abstract

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.

Synthesis of Cubic Ni(OH)2 Nanocages Through Coordinating Etching and Precipitating Route for High-Performance Supercapacitors

“…Thereinto, PCs governed by redox on/near the surface of transition metal oxide/hydroxide electrodes always have higher energy density than EDLCs and have become the hot issues in this field [5–10]. As a typical transition metal hydroxide, Ni(OH) 2 was reported as a high-performance electrode material for PCs due to the redox couple of Ni 3+ /Ni 2+ in an alkaline medium [11, 12]. Nevertheless, the acquired specific capacitance of Ni(OH) 2 is always much lower than the theoretical value because of the insufficient utilization of electrode materials.…”

Facile fabrication of hierarchical film composed of Co(OH)2@Carbon nanotube core/sheath nanocables and its capacitive performance

“…In order to improve the capacitive performances of the Co(OH) 2 based electrodes, various carbon materials, such as carbon nanotubes (CNTs) 1,10–15 and graphene, 16–21 are introduced to form carbon/Co(OH) 2 hybrids. Due to their high surface area and excellent conductivity, the carbon materials can act as structure matrix to enhance conductivity and to enlarge specific surface area.…”