Modification Strategies of Layered Double Hydroxides for Superior Supercapacitors

Layered double hydroxides (LDHs), as classic 2D materials, have received worldwide attention in electrochemical energy storage devices due to its superior ion insertion rate and ultrahigh specific capacitance. However, the poor conductivity, severe aggregation limited capacitance, and unsatisfied internal stability have become the main factors hinder its further development as the electrode of supercapacitor. In recent years, various strategies on the modification of the LDHs' structure, composition, properties, and fabrication have been demonstrated to effectively improve their electrochemical performance, and fruitful achievements have been made. However, there is a lack of systematic summary on the functional mechanisms and effects of various modification strategies. Herein, this review gives a comprehensive introduction of the modification strategies based on LDHs for superior supercapacitor, including active metal ions adjustment, intercalated ions adjustment, morphology optimization, conductivity enhancement and internal stability enhancement. Particularly, an in-depth and fundamental understanding on the effects and mechanisms of modification on LDHs' electrochemical properties and performance. Furthermore, the general performance metrics of above strategies, the potential directions and perspectives for further research are proposed.