A π–d conjugated metal–organic framework decorated on a MXene-carbon nanofiber as a self-standing electrode for flexible supercapacitors

Abstract

Flexible electrode materials have gained significant breakthroughs recently due to their freestanding nature and long-term stability. The integration of MXene into carbon nanofiber leads to improved conductivity and stability. Herein, we employed an electrospinning technique to prepare self-standing MXene (Ti₃C₂T_x) carbon nanofiber (MX-CNF), onto which a one-dimensional π–d conjugated conductive metal–organic framework (c-MOF) is uniformly coated, exhibiting outstanding properties. The enhanced specific capacitance and conductivity is due to π–d mode of electron transfer in c-MOF on MX-CNF leads to improved conductivity. The obtained composite material achieved a specific capacitance of 1076 F g⁻¹ with an excellent rate capability and superior cycling retention of 86.4% after 15 000 cycles owing to its self-standing nature and ultra-stability. The electrode materials show better conductivity, hydrophilicity, and flexibility. A fabricated flexible asymmetric energy storage device achieved an energy density of 45.7 W h kg⁻¹ with outstanding cycling stability. The flexible device was tested for different bending angles, maintaining its flexibility and ensuring no deformation occurred. The CV curves retains its orignal shapes at different bending angles. This work offers a new avenue for utilizing 1D conductive MOF on 2D material-based conductive nanofibers for flexible energy storage systems.