ABSTRACT
As a novel class of porous materials, metal-organic frameworks (MOFs) and their derived materials have attracted huge attention in recent years for next-generation electrochemical energy storage devices, especially for electrochemical capacitors (ECs) that combine the two features of high power density and high energy density of conventional capacitors and secondary batteries, owing to their high specific surface areas, controllable structures, and adjustable pore sizes. However, their intrinsic low electrical conductivity has restrained their applications. Recent developments in MOF-derived nanostructures with well-defined interior voids and enhanced conductivity have revealed extensive capabilities for promising energy storage and conversion, especially for high-rate or high-power energy storage, owing to the natural suitability of MOFs as versatile precursors and sacrificial templates for a wide variety of metallic/carbon-based nanomaterials. Herein, we conducted a timely and comprehensive review of the impressive advancements achieved in recent years on MOF-derived carbon coated nanocomposites (mainly their oxides, sulfides, and some hydroxides composites/hybrids) with synergistic effect (i.e., combined tremendous electrochemical active sites, excellent structural stability, and enhanced ionic/electronic transfer) for promising electrochemical capacitors (including supercapacitors, asymmetric/hybrid supercapacitors, freestanding/flexible supercapacitors). The major challenges, opportunities, and prospective solutions are also discussed for further development of MOF-based electrochemical capacitors with ultimate practical applications.
