Ce-MOF Coupled Mo 2 Ti 2 C 3 /Mo 2 TiC 2 MXene Interface Electrodes for High-Energy Hybrid Supercapacitors

The integration of metal–organic frameworks with two-dimensional MXenes has emerged as an innovative approach to augment the electrochemical performance of supercapacitors. Herein, cerium-based metal–organic framework (Ce-MOF)/MXene composites were synthesized using Mo2Ti2C3 and Mo2TiC2 MXenes, through a facile in situ co-precipitation process. XRD, Raman, SEM, and TEM analysis results of Ce-MOF/MXene composites revealed preferential growth of Ce-MOF rods along the edges of MXene layer and also facilitated the edge-to-edge stacking of the MXene layers in Ce-MOF/Mo2Ti2C3 and Ce-MOF/Mo2TiC2 composites. The resulting hybrid composites exhibited increased surface area and enhanced conductivity. The polaronic electron transfer from the redox-active Ce-MOF, combined with the electric double-layer capacitance of the highly conductive MXene, enhances the capacitance and cycling stability of the composites, with Mo2Ti2C3-based hybrids exhibiting superior charge storage capacity. Electrochemical performance indicates that the Ce-MOF/Mo2Ti2C3 and Ce-MOF/Mo2TiC2 composites exhibit high specific capacitances of 3109.7 F g–1 and 2979.3 F g–1 at 2 A g–1, respectively, representing significant improvements over pure Ce-MOF. The Ce-MOF/Mo2Ti2C3 composite exhibited improved cyclic stability, retaining 90.7% of its initial capacitance after 5000 GCD cycles. An asymmetric Ce-MOF/Mo2Ti2C3//rGO device was fabricated to assess practical usability, achieving a peak energy density of 51.43 Wh kg–1 with a power density of 1800 W kg–1. A Ce-MOF/Mo2Ti2C3//AC asymmetric coin cell was also fabricated, with a maximum energy density of 22.6 Wh kg–1 obtained at a power density of 714 W kg–1. The results indicate that Ce-MOF/MXene composites possess significant potential as electrode materials for innovative hybrid supercapacitors.