Sulfidation-induced ZIF-67 melting and remodeling to enhance its interfacial bonding with hollow carbon microtubes for improving capacitive performance

A robust interfacial bonding between CoS 2 and porous carbon with hierarchical ion fast channels is crucial for fabricating capacitive materials with high stability and rate performance. Herein, a method for high-temperature sulfidation-induced ZIF-67 melting and remodeling at the surface of cotton-derived hollow tubular carbon fiber is employed to achieve the interfacial welding of porous carbon/CoS 2 with carbon fiber, thereby constructing a vascular-like scar-shaped CoS 2 -C C -C KF . Through the in-situ reconfiguration of ZIF-67-derived carbon framework mediated by Co 2+ /2-MIM molar ratio, CoS 2 -C C -C KF achieves the multiscale collaboration among the conductive network (cotton fiber-derived carbon, C KF ), the interface bridging layer (ZIF-67-derived carbon, C C ), and the active pseudocapacitive CoS 2 nanoparticles, forming an integrated ionic-electronic conductor hierarchical architecture. CoS 2 -C C -C KF exhibits a low electron transfer impedance of 0.15 and a high ionic diffusion coefficient of 4.7 × 10 −5  cm 2  s −1 after calculation. CoS 2 -C C -C KF exhibits a specific capacitance of 997.4 F g −1 at a current density of 1 A g −1 , and it still maintains 81 % of its specific capacitance at 10 A g −1 , which is higher than that of CoS 2 -C A -C KF (375.0 F g −1 , 69 %) and CoS 2 -C B -C KF (638.0 F g −1 , 75 %). The assembled asymmetric supercapacitor achieves a high energy density of 47.4 Wh kg −1 at 375.0 W kg −1 and exhibits excellent cycle stability (maintaining 81 % capacity after 10,000 cycles). These results demonstrate that the melting reconstruction strategy of ZIF-67 on carbon substrate can enhance the interfacial bonding strength of porous carbon/ CoS 2 , thereby improving their cycling stability in supercapacitors.