Hierarchical Polyimide‐Covalent Organic Frameworks Carbon Fiber Structures Enhancing Physical and Electrochemical Properties

The multifunctionality of carbon fiber (CF) is being extensively explored. Herein, polyimide covalent organic frameworks (PI‐COFs) are grafted bound to CF to enhance their mechanical and electrochemical properties. Here, a range of COF scaffolds are grafted to the surface of CFs via a two‐step functionalization. First, melamine is tethered to the fiber surface to provide an anchoring point for the COFs followed by a “graft from” approach to grow three different sized PI‐COFs utilizing three differently sized dianhydride, PMDA to form MA‐PMDA , NTCDA to form MA‐NTCDA, and PTCDA to form MA‐PTCDA COFs. These COFs increase the capacitance of CF by a maximum of 2.9 F g −1 (480% increase) for the MA‐PTCDA , this coincides with an increase in interfacial shear strength by 67.5% and 52% for MA‐NTCDA and MA‐PTCDA, respectively. This data represents that the first‐time CF has been modified with PI‐COFs and allows access to COF properties including their porosity and CO 2 capture ability while being attached to a substrate. This may lead to additional high‐value recyclability and second‐life applications for CFs.