Insights on Ni-based layered double hydroxides for electrochemical supercapacitors: Underlying aspects in rational design and structural evolution

Currently, supercapacitors are acknowledged as potential green energy storage devices (ESDs) ascribed to their low weight, excellent power density, superb charging rate, and very-long durability. Nevertheless, the real-life application of supercapacitors is significantly limited from their lower energy density. Electrode materials are acted a vital role to determining the overall performance of supercapacitors. Thus, the synthesis of active electrode materials is one of the most important stages in the fabrication of high-performance supercapacitors. In recent time, transition metal-layered double hydroxides (LDHs) are perceived as talented electrodes for supercapacitors by reason of their unique layered structure, huge surface area, excellent specific capacitance, effective redox reaction, inexpensive, and environmentally friendly. Particularly, Ni-based LDHs materials have shown an excellent electrochemical performance in supercapacitors, which is attributed to the high theoretical capacitance of Ni(OH)2 (2082 F g−1). Therefore, in the present review, the recent progress of designing and synthesizing the Ni-based LDHs (NiM (M = Al, Co, Fe, Mn, V, Cr and Ga)-LDHs) and their composites as electrodes for constructing the supercapacitors are analyzed and summarized. The current challenges and future perspectives of the Ni-based LDHs electrodes for the further development of supercapacitors are also proposed. Therefore, this review will be provided the significant insights to design high-performance Ni-based LDHs materials for supercapacitor applications.