UV-cured gel polymer electrolytes with improved stability for advanced aqueous Li-ion batteries.

We report the development of a new class of "water-in-salt" electrolytes based on UV photopolymerized acrylic polymers. Incorporation of "water-in-bisalt" in a polymer matrix reduces water activity, expands the electrochemical stability window to 4.1 V, and dramatically improves cycle life in full cells with lithium titanate anodes compared to liquid water-based electrolytes.