An ultrathin natural cellulose based hydrogel membrane for the high-performance quasi-solid-state zinc-ion batteries

Aqueous zinc-ion batteries (ZIBs) are regarded as promising candidates for next-generation energy storage systems due to their high capacity, inherent safety, and cost-effectiveness. However, the practical application of ZIBs is currently hindered by the insufficient stability of the zinc metal electrode and the spontaneous growth of dendrites during operation. Furthermore, the use of petroleum-based materials in batteries raises environmental concerns that must be addressed. This study proposes a natural cellulose-based biodegradable hydrogel membrane with an ultrathin and non-porous structure. Paper scraps are utilized as raw materials, and DMAc/LiCl serves as the dissolution system. The quasi-solid cellulose membrane demonstrates a high liquid absorption ability, favorable mechanical properties (39.5 MPa), excellent ion conductivity (0.643 mS cm⁻¹), a wide electrochemical window (1.6 V), and a low activation energy for Zn²⁺ conduction (3.195 kJ mol⁻¹). The Zn//Zn symmetric battery, assembled with the cellulose membrane, exhibits prolonged reversible Zn²⁺ stripping/plating behavior (up to 1800 h at 1 mA cm⁻²), highlighting its superior capability to suppress dendrite formation. Additionally, the corresponding Zn//V₂O₅ battery shows enhanced electrochemical stability, long cycle life, and high capacity. This research provides valuable insights for the development of polymer electrolytes that enable the realization of safe, lightweight, and environmentally friendly aqueous ZIBs.