A Strong and Tough Ion-gel Enabled by Hierarchical Meshing and Ion Hybridizations Collaboration

Ion-gels, with inherent flexibility, tunable conductivity, and multi-stimulus response, have attracted significant attention in flexible/wearable electronics. However, the design of ion-gels that exhibit both strength and toughness is challenging. In this study, a novel ion-gel design is proposed that mimics the hierarchical meshing structure of leaves in combination with ion hybridization. Polyacrylamide (PAM) is incorporated in TEMPO oxidized cellulose nanofibers (TOCNFs) clusters by in situ polymerization, generating a hydrogel with micro/nanoscale entangled networks. Replacement of water by a metal halide ionic liquid ([BMIm]Zn_xCl_y) in the hydrogel resulted in the formation of an ion hybrid network with supramolecular interactions. The integration of the PAM/TOCNF polymer network with [BMIm]Zn_xCl_y resulted in ion-gels with high strength (5.9 MPa), toughness (22 MJ m⁻³), and enhanced elastic modulus (30 MPa) combined with non-flammability, heat and cold resistance. While having fast responsiveness (36 ms) of sensing signal and stability of power supply even at 4000 cycle collisions. Stable signal output even at high (200 °C) /sub-zero temperatures. The proposed strategy offers a new approach to the material design of flexible/wearable electronics.