High-Performance Zwitterionic Hydrogel Polymer Electrolytes for Aqueous Zinc-Ion Batteries: Superior Ionic Conductivity and Stability

초록

We developed hydrogel polymer electrolytes for use in aqueous zinc-ion batteries. Aqueous zinc batteries face challenges related to dendrite formation and corrosion at the zinc metal anode, primarily stemming from the strong interaction between zinc ions and water molecules. To address this, we designed hydrogel polymer electrolytes, composed of acrylamide (AM) and zwitterion, such as vinyl imidazole propane sulfonate (VIPS), as monomers, vinyl silica nanoparticles (VSN) as cross-linkers, and zinc sulfate (ZnSO4) and lithium chloride (LiCl) as salts, through UV polymerization. The resulting hydrogel polymer electrolyte [P(AM-co-IPS)-ZnSO4/LiCl] exhibited high ionic conductivity (sigma(DC) = 3.5 x 10(2) S/cm) and remarkable flexibility (elongation at break = 321%) at 298 K. The addition of zwitterion and lithium chloride stabilized the solvation structure of zinc salts, leading to a reduction in melting points (from -25.4 to -33.3 degrees C), hydrogen evolution potential (HER, -52 mV), and corrosion current (1840 mu A). The zinc symmetric cell demonstrated that our electrolyte not only showed a high zinc ion transference number (t(Zn2+) = 0.7), but also maintained stable cell operation for over 400 hours, due to the effective ion transport channels facilitated by zwitterions.

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