High-Modulus Cellulose Nanofiber Ionogels for Energy Storage

High Resolution Image Download MS PowerPoint Slide Developing gel electrolytes that simultaneously achieve high mechanical stiffness and efficient ion transport remains a central challenge in ionogel design. Here, we investigate cellulose nanofiber (CNF)-based ionogels as sustainable platforms to address this limitation. The ionogels are fabricated via vacuum filtration, producing structurally uniform gels with high ionic liquid content (>66 wt %). Two imidazolium-based ionic liquids, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]) and 1-ethyl-3-methylimidazolium dicyanamide ([EMIM][DCA]), are incorporated to probe the role of anion chemistry. The ionogels exhibit Young’s moduli of 52.0 ± 4.6 MPa for CNF–TFSI and 78.7 ± 13.5 MPa for CNF–DCA, surpassing typical ionogels at similar ionic liquid loadings, while retaining ionic conductivities up to 1.6 ± 0.4 mS/cm. The differences in mechanical and transport properties are attributed to variations in ionic liquid–CNF interactions and mobility within the CNF network. Overall, this work demonstrates that ionic liquid chemistry can be strategically leveraged to tune mechanical and electrochemical performance in high-modulus ionogels and, to the best of our knowledge, represents the first report of CNF ionogels incorporating [EMIM][DCA] for supercapacitor applications.