Printed flexible supercapacitors utilizing composites of MWCNT/MOF ultrathin nanosheets: Exploring 1D/2D structural adjustment

Abstract

The self-stacking propensity of metal–organic frameworks (MOFs) during synthesis, combined with their intrinsic limitations in electrical conductivity and mechanical stability, constrains their utility as high-capacity energy sources in wearable electronics. Here, we employ a surfactant-assisted method to mitigate the Z-axis stacking of zinc metalloporphyrin organic frameworks (NMOFs), yielding ultrathin two-dimensional (2D) material sheets. By integrating carboxyl multiwalled carbon nanotubes into these nanosheets (denoted as C-NMOF-x), the lamellar structure of MOF is preserved while promoting the formation of rich multistage micropores and continuous conductive channels. This structural refinement remarkably enhances electrochemical properties, including capacitance, electronic conductivity, and cycling stability. Leveraging synergistic interactions, the resulting C-NMOF-4 composite achieves a specific capacitance of 0.152 mAh/g in a three-electrode system at a current density of 1 A/g. Furthermore, the modulated C-NMOF-4 composites are successfully formulated into homogeneous e-inks suitable for dispensing printing, enabling the mass production of flexible micro-supercapacitors (MSCs). Notably, these MSCs maintain 95 % of their capacitance even after 180° bending under wearable conditions. This surface and interface microstructure modulation strategy holds promise for enhancing the synergistic coupling effects of 2D materials and offers new avenues for the application of innovative 2D materials in wearable electronics.