Recent advances on two-dimensional NiFe-LDHs and their composites for electrochemical energy conversion and storage

Improving the performance of advanced energy conversion and storage equipments has always been a key issue in energy research. In recent years, layered double hydroxides (LDHs), especially NiFe-LDHs, have been widely used in catalysts, photoactive materials, acid absorbers, supercapacitors and other fields because of their versatility and high efficiency. In addition, due to its unique layered structure and fascinating characteristics, two-dimensional (2D) NiFe-LDHs materials show excellent performance in various energy conversion and storage fields. This review concentrated on rationally designing of 2D NiFe-LDHs by various methods including co-precipitation method, hydrothermal treat, ion exchange, and electrodeposition method. We describe the morphology and interfacial design of 2D NiFe-LDHs and their composites, among which these 2D materials usually take on nanoscale shapes and they adopt shell-core structure, heterostructure, and others. After that this paper expounds advanced characterization technologies to analyse these materials. This review has summarized their electrochemical energy conversion and storage applications. Finally, the future challenges and prospects of 2D NiFe-LDHs materials in energy storage devices and other fields are summarized.