Emerging crystalline porous materials as a multifunctional platform for electrochemical energy storage.

Metal-organic frameworks (MOFs) and covalent-organic frameworks (COFs) are two emerging and explosively growing families of crystalline porous materials (CPMs). These robust frameworks are characterized by their extraordinary porosity, tremendous structural diversity, and versatile functional tunability with precision at the molecular level. In this review, we present recent milestones of MOFs and COFs in the fields of batteries and supercapacitors, two important technologies in electrochemical energy storage (EES), and highlight the functions that a CPM can offer in EES devices, including the storage of electrochemical energy, stabilization of electrode materials, pathways for charge transport, manipulation on mass transport, and promotion of electrochemical reactions. Key requirements for each function are discussed, with future directions provided for further development.