Thermal treatment for promoting interfacial interaction in Co-BDC/Ti3C2Tx hybrid nanosheets for hybrid supercapacitors.

The design and synthesis of high-performance metal-organic frameworks (MOFs)-based electrodes are important for hybrid supercapacitors (HSC). Herein, enhanced interfacial interaction in Co-BDC/Ti3C2Tx (denoted as CoTC) hybrid nanosheets is achieved through thermal treatment, giving remarkably improved capacity performance compared with CoTC. The low temperature annealing treatment enables modulation of the bridging bonds content of CoTC and thus regulates the interfacial coupling effect between Co-BDC and Ti3C2Tx. Moreover, both the detailed XPS and XANES analysis reveal that the strong interfacial interactions between the two components promote a partial electron transfer from Ti3C2Tx to Co-BDC through the Ti-O-Co interfacial bonds. Consequently, it endows the Co-BDC with enhanced conductivity as well as the higher valence of Ti species in Ti3C2Tx, hence contributes a remarkable enhanced specific capacity. This work will provide a pathway to design advanced MOF/MXene materials for HSC.