Application of metal–organic frameworks and their derivatives for lithium-ion capacitors

There is an urgent need for lithium-ion capacitors (LICs) that possess both high energy density and high power density to meet the continuously growing energy storage demands. LICs effectively balance the high energy density of traditional rechargeable batteries with the superior power density and long life span of supercapacitors (SCs). Nevertheless, the development of LICs is still hampered by the challenges of limited kinetic processes and capacity mismatch between the cathode and anode. Metal-organic frameworks (MOFs) and their derivatives have garnered significant attention owing to their extensive specific surface area, rich pore structures, diverse topologies, and customizable functional sites, making them compelling candidate materials for achieving high-performance LICs. MOF-derived carbons, known for their exceptional electronic conductivity and extensive surface area, provide improved charge storage and rapid ion transport. MOF-derived transition metal oxides contribute to high specific capacities and improved electrochemical stability. Additionally, MOF-derived metal compounds/carbons provide synergistic effects that enhance both the capacitive and Faradaic reactions, leading to superior overall performance. In this review, the recent advancements in MOFs and their derivatives for LICs are presented. The review begins with an overview of the fundamental principles of LICs, followed by an exploration of synthesis strategies and ligand selection for MOF-based composite materials. It then analyzes the advantages of original MOFs and their derived materials, such as carbon materials and metal compounds, in enhancing LIC performance. Finally, the review discusses the major challenges faced by MOFs and their derivatives in LIC applications and offers future research directions and recommendations.