Ti3C2Tx MXene embedded metal–organic framework-based porous electrospun carbon nanofibers as a freestanding electrode for supercapacitors

Abstract

Rational modification of Ti₃C₂T_x MXenes for the preparation of freestanding and flexible carbon-based electrodes with great prospects for an energy storage facility is a crucial task for new-generation supercapacitors. Herein, a novel Ti₃C₂T_x MXene-decorated porous carbon nanofiber (PCNF) freestanding/flexible electrode is engineered through a sequential approach of electrospinning, in situ growth of ZIF67, and a carbonization process. By varying the concentration of MXenes in the fiber, the electrochemical performance of a set of MXene-integrated PCNFs is investigated, and flexible symmetric and asymmetric supercapacitor devices are assembled. The optimized MX-5@PCNF achieves a specific capacitance of 572.7 F g⁻¹ at 1 A g⁻¹ with high cycling stability (96.4% capacitance retention after 10 000 cycles) and superior rate capability (71.24% at 30 A g⁻¹). Furthermore, MX-5@PCNF-based flexible symmetric and asymmetric (Co₃O₄@NF//MX-5@PCNF) devices furnish high energy densities of 22.53 W h kg⁻¹ and 74.2 W h kg⁻¹, respectively, along with a long life cycle, ideal coulombic efficiency, and rate capability, demonstrating their practical applicability. This study provides an alternative strategy to prepare MXene-decorated PCNF freestanding electrodes with high performance, and the technique can be extended to other 2D MXenes for designing efficient electrodes for flexible supercapacitors.