Recent Progress in Two-Dimensional Layered Double Hydroxides and Their Derivatives for Supercapacitors.

High-performance supercapacitors have attracted great attention due to their high power, fast charging/discharging, long lifetime, and high safety. However, the generally low energy density and overall device performance of supercapacitors limit their applications. In recent years, the design of rational electrode materials has proven to be an effective pathway to improve the capacitive performances of supercapacitors. Layered double hydroxides (LDHs), have shown great potential in new-generation supercapacitors, due to their unique two-dimensional layered structures with a high surface area and tunable composition of the host layers and intercalation species. Herein, recent progress in LDH-based, LDH-derived, and composite-type electrode materials targeted for applications in supercapacitors, by tuning the chemical/metal composition, growth morphology, architectures, and device integration, is reviewed. The complicated relationships between the composition, morphology, structure, and capacitive performance are presented. A brief projection is given for the challenges and perspectives of LDHs for energy research.