Conductive metal-organic frameworks with redox activity as electrode materials for rechargeable batteries

Two-dimensional conductive metal-organic frameworks (2D c-MOFs) with high flexibility in structure design and functionalization have inspired numerous research interests as promising multifunctional materials due to their porous structure, high conductivity, and rich redox active sites. This review offers a concise overview of 2D c-MOF syntheses and their applications in rechargeable batteries. The electron transport mechanism of 2D c-MOFs will be briefly introduced first. Then we discuss the designs and syntheses of 2D c-MOFs, emphasizing the conjugate structure for high conductivity and the redox activity for efficient energy storage. The electrochemical behaviors of the 2D c-MOFs in different rechargeable battery systems are summarized with attention to their structure-performance correlations and storage mechanism. Particular attention is paid to the significant applied potential of 2D c-MOFs in the Na-ion batteries (NIBs) and K-ion batteries (KIBs), which are more sustainable battery chemistries but are plagued by the dissatisfactory battery performances due to the large size of the Na⁺ and K⁺. The challenges and opportunities regarding their efficient synthesis and rechargeable battery applications are also discussed. We expect this review will spark new endeavors to promote the further development of 2D c-MOFs for advanced rechargeable batteries.