Recent progress in emerging metal and covalent organic frameworks for electrochemical and functional capacitors

Abstract

Recently, metal and covalent organic frameworks (MOFs and COFs) and their derivatives have received significant attention as advanced electrode materials owing to their diverse topology, tunable porosity, well-defined crystalline structure, and abundant redox active sites. Herein, we provide a systematic and comprehensive review of the key fundamental aspects of MOFs, COFs, and their derivatives, which can be classified into 12 types. The chemical and physical features, energy storage mechanisms, and structure/property correlations of the 12 types of MOFs, COFs, and their derivatives are discussed by targeting performance- and functionality-oriented supercapacitor (SC) applications. In addition to the controllable structure and adjustable surface chemistry of pristine MOFs and COFs, chemical modification by metallization, carbonization, activation, metal and non-metal doping, and hybridization for the rational design of derived materials are addressed. Recent advances and challenges in the SC applications of MOFs, COFs, and their derivatives are discussed by covering performance-oriented SCs, including electrochemical double-layer capacitors, pseudocapacitors, and hybrid SCs, and functionality-oriented SCs, such as flexible, micro, and self-powered SCs. Finally, our perspective on the current impediments and future direction of this field is provided to facilitate the practical applications of MOFs, COFs, and their derivatives.