Synthesis of Ni/Co/Al-layered triple hydroxide@brominated graphene hybrid on nickel foam as electrode material for high-performance supercapacitors

Abstract

The determined need for a sustainable energy economy has evoked the increasing interest of researchers concerning the discovery of smart material designs of layered double hydroxide (LDH) nanocomposites for energy-based applications. This paper presents a novel method for the direct growth of brominated graphene and layered triple hydroxide (LTH) on 3D nickel foam (NF) as a supercapacitor electrode by a facile one-step in situ crystallization hydrothermal method. Subsequently, the as-synthesized NCA-L@BG-NF hybrids were characterized by TEM, SEM, HRTEM, XRD, FT-IR, RAMAN, XPS, and EDS. Moreover, the electrochemical performance disclosed that by fine-tuning the Ni/Co/Al mole ratios, it was possible to obtain optimized ratio of NCA-L@BG-NF-3 to display the maximum specific capacity of 1998 C g⁻¹ at 6 A g⁻¹, excellent rate capability of 75.3% at 20 A g⁻¹, and excellent cyclic stability of ∼91% capacitance retention after 2000 cycles at 20 A g⁻¹ with 100% coulombic efficiency. Furthermore, the greater electrochemical performance of LTH was achieved and synergistically strengthened with a high surface area provided by the conducting brominated graphene oxide framework directly grown on a 3D porous NF to form a binder-free electrode, which could improve the electrochemical performance in terms of charge transport and storage. Accordingly, these remarkable properties show that NCA-L@BG-NF-3 may be considered as a promising candidate for high-performance supercapacitor applications.