Scalable 2D/2D Assembly of Ultrathin MOF/MXene Sheets for Stretchable and Bendable Energy Storage Devices

Scalable assembly of two dimensional (2D) lamellar nanomaterials for deformable films has potential in wearable energy storage devices, but overcoming the trade-off in mechanical and energy storage properties is a challenge. Here, a blade-coating strategy is reported to develop highly stretchable and bendable metal-organic frameworks/large-sized Ti3C2Tx MXene (MOF/LMX) composite films on the pre-stretched elastomer substrates. The LMX sheets serve as conductive scaffolds for loading the small-sized ultrathin MOF sheets (SUMOFs), resulting in an improved tensile strength (approximate to 97 MPa) of the films, which guarantees their structural integrity when forming a wavy structure on a relaxed substrate. In addition, SUMOFs incorporated in-between LMX layers not only expose active redox sites by mitigating the intrinsic self-restacking of MOF but also accelerate the electron transfer in the redox reaction process revealed through the density functional theory calculations. As a result, the composite films deliver high electrical conductivity (3244 S cm-1) and energy storage capability (1238 F g-1). When assembled into an asymmetric supercapacitor device, it also exhibits stable performances under different bending and stretching states. Thus, the development of conducting and deformable MOF-based films with high mechanical, electrical, and energy storage properties enables their potential commercial applications for wearable electronics. A blade-coating method to achieve the first large-scale production of stretchable small-sized ultrathin metal-organic framework (MOF) and large-sized MXene (LMX) hybrid films. This work offers an alternative strategy to achieve the first MOF-based stretchable films with the addition of LMX sheets as support, which can be extended to other rigid materials for wearable energy storage devices and even other electronics.image