Rechargeable High-Areal Capacity Ag–Zn Batteries Enabled by Tunable-Composition Alkaline Copolymer Electrolytes

We report polymer electrolytes for high areal capacity rechargeable Ag–Zn alkaline batteries. Using initiated chemical vapor deposition (iCVD), we deposit submicrometer-thick copolymers of divinylbenzene (DVB) and 4-dimethylaminomethylstyrene (DMAMS) on two-dimensional and three-dimensional substrates. We convert the as-deposited copolymer p[DVB-DMAMS] into an anion-conducting electrolyte by quaternizing the tertiary amines in DMAMS followed by ion exchange with OH– to form p[DVB-DMAMS+(OH–)]. The highest performing water-swelled polymer electrolyte supports Ag–Zn redox without dissolved salts and exhibits single-ion OH– conductivity approaching 1 × 10–4 S cm–1. We demonstrate a solid-state battery comprising opposing Ag and Zn sponge electrodes coated with submicrometer-thick p[DVB-DMAMS+(OH–)] with an additional 300 μm-thick freestanding layer of the same copolymer between the electrodes serving as a macroscale separator and electrolyte. These cells deliver average areal capacities exceeding 7.9 mAh cm–2 (one of the highest reported for Ag–Zn) with Coulombic efficiency reaching 98%.