Decoding Dual-Ion Synergy in AlCl<sub>3</sub>/ZnCl<sub>2</sub> Hydrates: An Atomic “Interaction–Penetration–Dispersion” Mechanism for Ambient Cellulose Valorization
Xin Li, Zhonghao Chen, Xi Guan, Huicong Jiang, Ming Yan, Lili Zhang, Jinxia Ma, Lei Wang, Zhiguo Wang
Abstract
While the inorganic salt systems have demonstrated ambient cellulose dissolution, the atomic-scale mechanisms governing their unparalleled efficiency and sustainability remain unresolved. Here, we advance the typical inorganic salt solvent of the AlCl 3 /ZnCl 2 /H 2 O system by unraveling the hierarchical “interaction–penetration–dispersion” mechanism through multidimensional characterization and simulations. High-charge-density Al 3+ ions initiate hydrogen bond disruption via strong electrostatic interactions (interaction), while their small hydrated radius enables ultrafast fibril infiltration (penetration). Concurrently, Zn 2+ ions stabilize dissolved chains through solvation shielding (dispersion), achieving complete dissolution of cellulose within 10 min, 4-fold faster than single-ion ZnCl 2 systems. Density functional theory confirms thermodynamic spontaneity (Δ G = −0.59 eV), and life cycle assessment demonstrates an 85% lower carbon footprint of 2.94 kg CO 2 -eq/kg of bioplastics compared to polyvinyl fluoride plastics. The regenerated cellulose films exhibit exceptional mechanical strength (94.9 MPa) and rapid biodegradability (100% degradation in soil within 20 days), addressing both performance and environmental demands. We establish universal design principles for green solvent engineering by correlating hydration-regulated ionic ratios with dissolution kinetics. This work bridges the gap between fundamental ion–cellulose dynamics and scalable production of multifunctional materials, including conductive hydrogels (41.72 mS/cm), ultralight aerogels (829.4 kPa), and flexible fibers, propelling sustainable applications in flexible electronics, eco-packaging, and eco-textiles.