Molecularly Engineered Hydrogel Electrolyte Embedded with Multifunctional Oxygen-Rich Macrocyclic Units for Uniform Zinc Deposition.

Hydrogel electrolyte has emerged as an effective strategy for stabilizing zinc anode. Despite certain advancements in network design, solely relying on simple combinations of traditional polymer chains or single-function monomers is far from satisfactory in overcoming multiple challenges faced by zinc-ion battery. Herein, a novel multifunctional monomer, benzo-15-crown-5-acrylamide (BCAm), is designed and introduced into hydrogel network (PBCM-HE), aiming to regulate solvation sheath structure with supramolecular macrocyclic units. Specifically, rigid benzene rings in BCAm units can stabilize conformation of crown ether and bestow PBCM-HE excellent mechanical properties with tensile-strength of 105 kPa and compressive-strength of 0.6 MPa. Critically, the locally electron-rich ether bonds in supramolecular macrocycle can optimize solvation structure of hydrated zinc ions and promote ion transport, stabilizing interface interaction between electrolyte and Zn anode. Given this, PBCM-HE possesses outstanding ionic conductivity (61.7 mS cm) and remarkable transference number (0.86). Besides, the Zn||PBCM-HE||MnO full cells show excellent discharge specific capacity of 290.9 mAh g at 0.1 C with Zn uniform deposition. This work innovatively develops a novel hydrogel electrolyte network with multifunctional monomer through one-step polymerization, providing new insights and possibilities for monomer design and selection in hydrogel electrolytes, further paving the way for exploring high-performance electrolytes in zinc-based devices.