Progress of layered double hydroxide-based materials for supercapacitors

Nowadays, supercapacitors have been received widespread interests because of large specific capacitance, excellent cycle life, high power density and energy density, and wide operating temperature range. Electrode materials as an important component of supercapacitors directly decide the electrochemical performances. Layered double hydroxides (LDHs) are emerging in the field of electrode materials because of their unique 2D layer morphology, simple preparation method, large specific surface area and high theoretical specific capacitance. In this paper, the methods for the preparation of LDHs in recent years are reviewed, while different methods resulting in different properties are presented. In addition, some recent methods for the modification of LDHs are demonstrated, from content composition to structural changes giving rise to different properties. Furthermore, various types of LDHs used for supercapacitors are presented, the electrochemical performances are displayed, and their energy storage mechanism are meanwhile illuminated in detail. This article aims to elucidate the usage of LDHs for supercapacitors, as well as hopes to provide a reference for the further research based on these promising materials.