Flaxseed-based green electrolyte enabling high electrochemical stability for advanced zinc ion batteries

This study presents a green and sustainable electrolyte derived from flaxseeds (FS) aimed at enhancing the electrochemical stability of zinc-ion batteries (ZIBs), thereby reducing the occurrence of free water molecules and alleviating the hydrogen evolution reaction (HER) that contributes to the development of zinc (Zn) dendrites. The abundant hydroxyl groups present in polysaccharides and phenolic compounds within the flaxseeds coordinate with Zn2+, modifying the solvation sheath and reducing HER activity. Zn//Zn symmetric cells utilizing the FS-based electrolyte exhibited remarkably stable cycling for 3000 h at a current density of 1.0 mA cm−2 (1.0 mAh cm−2) and 2500 h at 2.0 mA cm−2 (2.0 mAh cm−2). Zn//V2O5 full cells delivered a discharge capacity of 233.8 mAh g−1 at 0.2 A g−1 and excellent rate capability across a wide current density range of 0.2–10 A g−1 . The ex situ SEM and XRD results confirmed uniform Zn deposition along the (002) plane without dendrite formation. This work demonstrates a biomass-derived, low-cost electrolyte formulation strategy that effectively stabilizes Zn interfaces, providing a green and efficient pathway for next-generation zinc-ion batteries.